diff --git a/packages/core/src/agent.ts b/packages/core/src/agent.ts
index 64d7c8c..b79bee8 100644
--- a/packages/core/src/agent.ts
+++ b/packages/core/src/agent.ts
@@ -57,6 +57,7 @@ import { INPUT_SUBAGENT_NAME } from "./environment/tools/input-subagent.js";
 import type { CompactionSettings } from "./engine/context-engine.js";
 import type {
   GenerativeModelConfig,
+  ProxyEnvPolicy,
   SubagentRunner,
   ThinkingLevelName,
   ToolDefinition,
@@ -77,15 +78,15 @@ export interface CreateAgentOptions {
   /** Local data root directory; defaults to `resolveRoot()` (PENGUIN_HOME or ~/.penguin/data). */
   root?: string;
   /**
-   * When it returns true, the proxy variables (HTTP_PROXY / HTTPS_PROXY / ALL_PROXY;
-   * NO_PROXY is kept) are stripped from exec_command subprocess environments of every
-   * Session this Agent creates or resumes — and of its subagents' Sessions, which
-   * inherit the getter. The Web server threads its admin-level "use system HTTP proxy"
-   * switch (off state) through here; the getter is re-read at every command spawn, so a
-   * toggle needs no restart. Absent = proxy allowed (SDK/CLI standalone use follows the
+   * Proxy policy for exec_command subprocess environments of every Session this Agent
+   * creates or resumes — and of its subagents' Sessions, which inherit the getter (see
+   * {@link ProxyEnvPolicy}: strip the proxy variables, inject an explicit proxy over the
+   * inherited env, or null = pass through). The Web server threads its admin-level proxy
+   * settings through here; the getter is re-read at every command spawn, so a settings
+   * change needs no restart. Absent = pass through (SDK/CLI standalone use follows the
    * user's own shell environment).
    */
-  stripProxyEnv?: () => boolean;
+  proxyEnv?: () => ProxyEnvPolicy | null;
 }
 
 export interface CreateSessionOptions {
@@ -159,15 +160,15 @@ export function metaMaxTokens(budget: number, modelCap: number | undefined): num
 export async function createAgent(opts: CreateAgentOptions = {}): Promise<Agent> {
   const state = await loadOrInitAgentState(opts);
   const projectConfig = await loadProjectConfig(state.root, state.projectId);
-  return new Agent(state, projectConfig, opts.stripProxyEnv);
+  return new Agent(state, projectConfig, opts.proxyEnv);
 }
 
 export class Agent {
   constructor(
     readonly state: AgentState,
     readonly projectConfig: ProjectConfig,
-    /** See {@link CreateAgentOptions.stripProxyEnv}; forwarded into every Session's Environment. */
-    private readonly stripProxyEnv?: () => boolean,
+    /** See {@link CreateAgentOptions.proxyEnv}; forwarded into every Session's Environment. */
+    private readonly proxyEnv?: () => ProxyEnvPolicy | null,
   ) {}
 
   /**
@@ -598,10 +599,10 @@ export class Agent {
                 root,
                 projectId,
                 agentId,
-                // A child Agent loads its own vault/config, but the proxy-strip getter is
-                // host policy, not Agent state: the subagent's commands run in the same
-                // serving process, so they follow the same switch as the parent's.
-                ...(parentAgent.stripProxyEnv ? { stripProxyEnv: parentAgent.stripProxyEnv } : {}),
+                // A child Agent loads its own vault/config, but the proxy-env policy
+                // getter is host policy, not Agent state: the subagent's commands run in
+                // the same serving process, so they follow the same settings as the parent's.
+                ...(parentAgent.proxyEnv ? { proxyEnv: parentAgent.proxyEnv } : {}),
               })
             : parentAgent;
         // The child Session follows the PARENT Session, never the Project default: with the
@@ -744,7 +745,7 @@ export class Agent {
       ),
       services: { subagentRunner, ...(visionDescriber ? { visionDescriber } : {}) },
       ...(Object.keys(vault).length > 0 ? { vault } : {}),
-      ...(this.stripProxyEnv ? { stripProxyEnv: this.stripProxyEnv } : {}),
+      ...(this.proxyEnv ? { proxyEnv: this.proxyEnv } : {}),
     });
     const tools = await environment.listTools();
 
diff --git a/packages/core/src/environment/environment.ts b/packages/core/src/environment/environment.ts
index 8cb4d0b..bdcb1ed 100644
--- a/packages/core/src/environment/environment.ts
+++ b/packages/core/src/environment/environment.ts
@@ -110,10 +110,10 @@ export class Environment implements EnvironmentInterface {
     // The background session registry is created alongside Environment (one per Session) and
     // injected into whichever tools need it; all sessions are finalized together on dispose.
     // The vault environment variables are injected into child processes by the command session
-    // registry at spawn time (which also strips the proxy variables while stripProxyEnv says so).
+    // registry at spawn time (which also applies the proxyEnv policy — strip or inject).
     this.commandSessions = new CommandSessionManager({
       ...(config.vault !== undefined ? { vault: config.vault } : {}),
-      ...(config.stripProxyEnv !== undefined ? { stripProxyEnv: config.stripProxyEnv } : {}),
+      ...(config.proxyEnv !== undefined ? { proxyEnv: config.proxyEnv } : {}),
     });
     this.subagentSessions = new SubagentSessionManager();
     const services = {
diff --git a/packages/core/src/environment/tools/command/session-manager.ts b/packages/core/src/environment/tools/command/session-manager.ts
index f74b215..39a2518 100644
--- a/packages/core/src/environment/tools/command/session-manager.ts
+++ b/packages/core/src/environment/tools/command/session-manager.ts
@@ -11,6 +11,7 @@
  */
 import { ManagedSession } from "./session.js";
 import { BackgroundRegistry } from "../background/index.js";
+import type { ProxyEnvPolicy } from "../../../interfaces.js";
 
 /** Concurrent managed-session cap: evicts once exceeded (exited sessions first, otherwise LRU — killing a background process has bounded cost). */
 const MAX_SESSIONS = 64;
@@ -86,18 +87,26 @@ const STRIPPED_ENV_KEYS = new Set([
 ]);
 
 /**
- * Proxy variables removed IN ADDITION when the host asks for it (`stripProxyEnv`, see
- * {@link CommandSessionManager}): the Web server's "use system HTTP proxy" switch in the
- * off state must keep commands from inheriting the serving process's proxy environment
- * (design § "出网与系统代理"). NO_PROXY is deliberately NOT stripped — with no proxy
- * variables left it is inert, and removing it would change behavior for commands that
- * set their own proxy. Matched case-insensitively like {@link STRIPPED_ENV_KEYS}, which
- * also covers the conventional lowercase spellings (http_proxy etc.).
+ * Proxy variables removed IN ADDITION when the host supplies a proxy policy (`proxyEnv`,
+ * see {@link CommandSessionManager}): the Web server's proxy settings must keep commands
+ * from just inheriting the serving process's proxy environment.
+ * In `strip` mode NO_PROXY is deliberately NOT removed — with no proxy variables left it
+ * is inert, and removing it would change behavior for commands that set their own proxy.
+ * In `inject` mode the inherited NO_PROXY is replaced too (the policy carries the merged
+ * list), and ALL_PROXY stays removed rather than replaced: the explicit app-level proxy
+ * outranks ambient env wholesale. Matched case-insensitively like
+ * {@link STRIPPED_ENV_KEYS}, which also covers the conventional lowercase spellings
+ * (http_proxy etc.).
  */
 const PROXY_ENV_KEYS = new Set(["HTTP_PROXY", "HTTPS_PROXY", "ALL_PROXY"]);
 
-/** The host environment minus {@link STRIPPED_ENV_KEYS} (and {@link PROXY_ENV_KEYS} when asked). */
-function hostEnvForChild(stripProxy: boolean): NodeJS.ProcessEnv {
+/**
+ * The host environment minus {@link STRIPPED_ENV_KEYS}, with the proxy policy applied:
+ * `strip` removes {@link PROXY_ENV_KEYS}; `inject` additionally replaces NO_PROXY and
+ * sets the explicit proxy variables (both spellings — programs disagree on which they
+ * read); null passes the proxy variables through untouched.
+ */
+function hostEnvForChild(policy: ProxyEnvPolicy | null): NodeJS.ProcessEnv {
   const env: NodeJS.ProcessEnv = {};
   // Matched case-insensitively rather than deleting the upper-case spellings: Windows resolves
   // environment names without regard to case but stores whatever casing was written, so a
@@ -106,9 +115,18 @@ function hostEnvForChild(stripProxy: boolean): NodeJS.ProcessEnv {
   for (const [key, value] of Object.entries(process.env)) {
     const name = key.toUpperCase();
     if (STRIPPED_ENV_KEYS.has(name)) continue;
-    if (stripProxy && PROXY_ENV_KEYS.has(name)) continue;
+    if (policy !== null && PROXY_ENV_KEYS.has(name)) continue;
+    if (policy?.mode === "inject" && name === "NO_PROXY") continue;
     env[key] = value;
   }
+  if (policy?.mode === "inject") {
+    env.HTTP_PROXY = policy.url;
+    env.http_proxy = policy.url;
+    env.HTTPS_PROXY = policy.url;
+    env.https_proxy = policy.url;
+    env.NO_PROXY = policy.noProxy;
+    env.no_proxy = policy.noProxy;
+  }
   return env;
 }
 
@@ -121,16 +139,17 @@ export class CommandSessionManager {
   /** Agent vault environment variables: injected into the child process on every spawn (values never enter the model context, only the environment). */
   private readonly vault: Record<string, string>;
   /**
-   * When it returns true, {@link PROXY_ENV_KEYS} are removed from the child environment
-   * too. A getter rather than a boolean: the hosting server's "use system HTTP proxy"
-   * switch is toggled at runtime, and re-reading at every spawn makes the toggle reach
-   * Sessions that are already running. Absent = proxy allowed (SDK/CLI standalone use).
+   * Proxy policy for the child environment (see {@link ProxyEnvPolicy}: strip the proxy
+   * variables, inject an explicit proxy over the inherited ones, or null = pass
+   * through). A getter rather than a snapshot: the hosting server's proxy settings
+   * change at runtime, and re-reading at every spawn makes a change reach Sessions that
+   * are already running. Absent = pass through (SDK/CLI standalone use).
    */
-  private readonly stripProxyEnv: (() => boolean) | undefined;
+  private readonly proxyEnv: (() => ProxyEnvPolicy | null) | undefined;
 
-  constructor(opts?: { vault?: Record<string, string>; stripProxyEnv?: () => boolean }) {
+  constructor(opts?: { vault?: Record<string, string>; proxyEnv?: () => ProxyEnvPolicy | null }) {
     this.vault = opts?.vault ?? {};
-    this.stripProxyEnv = opts?.stripProxyEnv;
+    this.proxyEnv = opts?.proxyEnv;
   }
 
   /** Starts a command, returning an **unregistered** session (no process_id yet). */
@@ -144,10 +163,11 @@ export class CommandSessionManager {
       // Spread order is priority: vault overrides host variables of the same name, but must
       // come before HARDENED_ENV — the hardening entries (GIT_EDITOR/PAGER etc. that prevent
       // interactive hangs) must never be overridable by vault. The host side is stripped of
-      // the harness's own variables first (see STRIPPED_ENV_KEYS; plus the proxy variables
-      // when stripProxyEnv says so); the vault still wins, so a user who genuinely wants
-      // PORT — or a proxy — in commands can set it there.
-      env: { ...hostEnvForChild(this.stripProxyEnv?.() === true), ...this.vault, ...HARDENED_ENV },
+      // the harness's own variables first (see STRIPPED_ENV_KEYS) and has the proxyEnv
+      // policy applied (strip or inject); the vault still wins — over an injected proxy
+      // too — so a user who genuinely wants PORT, or their own proxy, in commands can set
+      // it there.
+      env: { ...hostEnvForChild(this.proxyEnv?.() ?? null), ...this.vault, ...HARDENED_ENV },
     });
   }
 
diff --git a/packages/core/src/interfaces.ts b/packages/core/src/interfaces.ts
index 88d403b..998f128 100644
--- a/packages/core/src/interfaces.ts
+++ b/packages/core/src/interfaces.ts
@@ -293,15 +293,32 @@ export interface EnvironmentConfig {
    */
   vault?: Record<string, string>;
   /**
-   * When it returns true, the proxy variables (HTTP_PROXY / HTTPS_PROXY / ALL_PROXY, any
-   * casing; NO_PROXY is kept) are stripped from exec_command / input_command subprocess
-   * environments. Threaded by the Web server from its admin-level "use system HTTP proxy"
-   * switch (off state); re-read at every spawn so a toggle needs no restart. Absent =
-   * proxy allowed (the default for SDK/CLI standalone use).
+   * Proxy policy for exec_command / input_command subprocess environments (see
+   * {@link ProxyEnvPolicy}). Threaded by the Web server from its admin-level proxy
+   * settings; re-read at every spawn so a settings change needs no restart. Absent, or a
+   * getter returning null = the host environment passes through unchanged (the default
+   * for SDK/CLI standalone use).
    */
-  stripProxyEnv?: () => boolean;
+  proxyEnv?: () => ProxyEnvPolicy | null;
 }
 
+/**
+ * Proxy policy applied to command subprocess environments (see
+ * {@link EnvironmentConfig.proxyEnv}):
+ * - `{ mode: "strip" }` — the proxy variables (HTTP_PROXY / HTTPS_PROXY / ALL_PROXY, any
+ *   casing) are removed; NO_PROXY is kept (inert without them, and commands that set
+ *   their own proxy still honor it). The hosting server's proxy switch in the off state.
+ * - `{ mode: "inject", url, noProxy }` — the explicit proxy wins over ambient env:
+ *   HTTP_PROXY / HTTPS_PROXY (plus their lowercase twins) are set to `url` and
+ *   NO_PROXY / no_proxy to `noProxy`, overriding inherited values; an inherited
+ *   ALL_PROXY (any casing) is removed for the same reason. The caller supplies `noProxy`
+ *   pre-merged (the hosting server includes the loopback names).
+ * - `null` (or no getter at all) — pass through unchanged.
+ * The Agent vault still overrides whichever of these the policy produced: a per-Agent
+ * explicit variable outranks the host-level policy.
+ */
+export type ProxyEnvPolicy = { mode: "strip" } | { mode: "inject"; url: string; noProxy: string };
+
 /**
  * An approved tool-call execution request.
  * Docs: /docs/interfaces § "ToolExecutionRequest and EnvironmentConfig".
diff --git a/packages/core/test/exec-session.test.ts b/packages/core/test/exec-session.test.ts
index 3bb69c6..894bd75 100644
--- a/packages/core/test/exec-session.test.ts
+++ b/packages/core/test/exec-session.test.ts
@@ -8,7 +8,7 @@ import path from "node:path";
 import { Environment, ManagedSession } from "../src/environment/index.js";
 import { toolCall } from "../src/omnimessage/index.js";
 import type { OmniMessage } from "../src/omnimessage/index.js";
-import type { ToolConfig, ToolDefinitionConfig } from "../src/interfaces.js";
+import type { ProxyEnvPolicy, ToolConfig, ToolDefinitionConfig } from "../src/interfaces.js";
 
 function execTool(overrides: Partial<ToolDefinitionConfig> = {}): ToolDefinitionConfig {
   return {
@@ -313,7 +313,7 @@ describe("harness environment variables never reach a spawned command", () => {
     process.env.HOST = "127.0.0.1";
     process.env.PENGUIN_CLI_ENTRY = "/opt/penguin/lib/dist/index.js";
     process.env.PENGUIN_WEB_DIST = "/opt/penguin/web";
-    // The desktop shell's process credentials (see design § "桌面端原型"): a leaked token
+    // The desktop shell's process credentials: a leaked token
     // would let an Agent-run command call the server's shutdown endpoint.
     process.env.PENGUIN_DESKTOP_TOKEN = "secret-desktop-token";
     process.env.PENGUIN_PORT_FILE = "/tmp/port-file";
@@ -407,14 +407,21 @@ describe("harness environment variables never reach a spawned command", () => {
   });
 });
 
-describe("proxy variables are stripped from commands when the host opts out", () => {
-  // The Web server's "use system HTTP proxy" switch (off state) threads stripProxyEnv
-  // through Agent -> Environment -> CommandSessionManager; standalone Environments (no
-  // getter) keep the historical pass-through.
+describe("proxyEnv policy governs the proxy variables commands inherit", () => {
+  // The Web server's proxy settings thread a ProxyEnvPolicy getter through
+  // Agent -> Environment -> CommandSessionManager: strip (switch off), inject (explicit
+  // address), or null (passthrough); standalone Environments (no getter) keep the
+  // historical pass-through.
   const KEYS = ["HTTP_PROXY", "HTTPS_PROXY", "ALL_PROXY", "NO_PROXY"] as const;
   const saved: Partial<Record<(typeof KEYS)[number], string | undefined>> = {};
-  let strip = true;
-  let stripEnv: Environment;
+  let policy: ProxyEnvPolicy | null = null;
+  let policyEnv: Environment;
+
+  const INJECT: ProxyEnvPolicy = {
+    mode: "inject",
+    url: "http://explicit.example:3128",
+    noProxy: "corp.example,localhost,127.0.0.1,::1",
+  };
 
   beforeEach(() => {
     for (const k of KEYS) saved[k] = process.env[k];
@@ -422,24 +429,24 @@ describe("proxy variables are stripped from commands when the host opts out", ()
     process.env.HTTPS_PROXY = "http://proxy.corp.example:8443";
     process.env.ALL_PROXY = "socks5://proxy.corp.example:1080";
     process.env.NO_PROXY = "localhost,127.0.0.1,::1";
-    strip = true;
-    stripEnv = new Environment({
+    policy = { mode: "strip" };
+    policyEnv = new Environment({
       workspaceDir: tmp,
       toolConfig: sessionConfig(),
-      stripProxyEnv: () => strip,
+      proxyEnv: () => policy,
     });
   });
   afterEach(() => {
-    stripEnv.dispose();
+    policyEnv.dispose();
     for (const k of KEYS) {
       if (saved[k] === undefined) delete process.env[k];
       else process.env[k] = saved[k];
     }
   });
 
-  it("HTTP(S)_PROXY/ALL_PROXY are removed, NO_PROXY stays (inert without them)", async () => {
+  it("strip: HTTP(S)_PROXY/ALL_PROXY are removed, NO_PROXY stays (inert without them)", async () => {
     const READ = KEYS.map((k) => `${k}=[' + (process.env.${k} ?? '') + ']`).join(" ");
-    const res = await runTool(stripEnv, "exec_command", {
+    const res = await runTool(policyEnv, "exec_command", {
       cmd: `node -e "console.log('${READ}')"`,
     });
     expect(res.output).toContain(
@@ -447,10 +454,10 @@ describe("proxy variables are stripped from commands when the host opts out", ()
     );
   });
 
-  it("a lowercase spelling is stripped too (the conventional POSIX form)", async () => {
+  it("strip: a lowercase spelling is stripped too (the conventional POSIX form)", async () => {
     process.env.https_proxy = "http://proxy.corp.example:8443";
     try {
-      const res = await runTool(stripEnv, "exec_command", {
+      const res = await runTool(policyEnv, "exec_command", {
         cmd: `node -e "console.log('s=[' + (process.env.https_proxy ?? '') + ']')"`,
       });
       expect(res.output).toContain("s=[]");
@@ -459,9 +466,54 @@ describe("proxy variables are stripped from commands when the host opts out", ()
     }
   });
 
-  it("the getter is re-read at every spawn, so a live toggle needs no new Environment", async () => {
-    strip = false;
-    const res = await runTool(stripEnv, "exec_command", {
+  it("inject: the explicit proxy overrides the inherited variables, both spellings", async () => {
+    policy = INJECT;
+    const READ =
+      "H=[' + (process.env.HTTP_PROXY ?? '') + '] h=[' + (process.env.http_proxy ?? '') + '] " +
+      "S=[' + (process.env.HTTPS_PROXY ?? '') + '] s=[' + (process.env.https_proxy ?? '') + ']";
+    const res = await runTool(policyEnv, "exec_command", {
+      cmd: `node -e "console.log('${READ}')"`,
+    });
+    expect(res.output).toContain(
+      "H=[http://explicit.example:3128] h=[http://explicit.example:3128] " +
+        "S=[http://explicit.example:3128] s=[http://explicit.example:3128]",
+    );
+  });
+
+  it("inject: NO_PROXY is replaced with the policy's merged list and ALL_PROXY is removed", async () => {
+    policy = INJECT;
+    const READ =
+      "N=[' + (process.env.NO_PROXY ?? '') + '] n=[' + (process.env.no_proxy ?? '') + '] " +
+      "A=[' + (process.env.ALL_PROXY ?? '') + ']";
+    const res = await runTool(policyEnv, "exec_command", {
+      cmd: `node -e "console.log('${READ}')"`,
+    });
+    expect(res.output).toContain(
+      "N=[corp.example,localhost,127.0.0.1,::1] n=[corp.example,localhost,127.0.0.1,::1] A=[]",
+    );
+  });
+
+  it("inject: the vault still wins — a per-Agent proxy outranks the injected one", async () => {
+    policy = INJECT;
+    const vaultEnv = new Environment({
+      workspaceDir: tmp,
+      toolConfig: sessionConfig(),
+      vault: { HTTP_PROXY: "http://vault.example:9999" },
+      proxyEnv: () => policy,
+    });
+    try {
+      const res = await runTool(vaultEnv, "exec_command", {
+        cmd: `node -e "console.log('H=[' + (process.env.HTTP_PROXY ?? '') + ']')"`,
+      });
+      expect(res.output).toContain("H=[http://vault.example:9999]");
+    } finally {
+      vaultEnv.dispose();
+    }
+  });
+
+  it("the getter is re-read at every spawn, so a live settings change needs no new Environment", async () => {
+    policy = null;
+    const res = await runTool(policyEnv, "exec_command", {
       cmd: `node -e "console.log('H=[' + (process.env.HTTP_PROXY ?? '') + ']')"`,
     });
     expect(res.output).toContain("H=[http://proxy.corp.example:8080]");
diff --git a/packages/desktop/src/os-proxy.ts b/packages/desktop/src/os-proxy.ts
index 4476a33..a0734ff 100644
--- a/packages/desktop/src/os-proxy.ts
+++ b/packages/desktop/src/os-proxy.ts
@@ -1,11 +1,15 @@
 /**
- * OS-proxy resolution for the embedded server (design § "出网与系统代理"): on the
- * desktop, "system proxy" means the real operating-system setting. The shell resolves
+ * OS-proxy resolution for the embedded server: on the desktop, "system proxy" means
+ * the real operating-system setting. The shell resolves
  * it through Electron's resolveProxy when forking the server and injects the result
  * into the child environment as HTTP_PROXY / HTTPS_PROXY — the server's dispatcher
- * (and, while the admin switch is on, agent commands) then honor it. Variables already
- * present in the shell's environment are never overridden (same idiom as
- * bundledShellEnv): an explicitly configured environment wins over the OS lookup.
+ * (while the admin app-proxy switch is on) and agent commands (while the agent-proxy
+ * switch is on) then honor it. Variables already present in the shell's environment are
+ * never overridden (same idiom as bundledShellEnv): an explicitly configured
+ * environment wins over the OS lookup. An admin-configured explicit proxy address
+ * (server_settings `proxyUrl`) in turn wins over BOTH at the server's dispatcher and in
+ * agent command env injection — what this module injects is only the "follow the system
+ * proxy" default the server falls back to.
  *
  * Only the entry point touches Electron, behind a dynamic import; the parsing and the
  * override check stay pure so they unit-test without an Electron runtime.
diff --git a/packages/docs/content/interfaces.en.md b/packages/docs/content/interfaces.en.md
index d3b6691..859fbb2 100644
--- a/packages/docs/content/interfaces.en.md
+++ b/packages/docs/content/interfaces.en.md
@@ -127,9 +127,14 @@ interface EnvironmentConfig {
   sessionScratchpadDir?: string;            // this Session's scratchpad (scratchpad/<sessionId>); enables truncated-output recovery
   services?: EnvironmentServices;           // runtime services injected into individual tools
   vault?: Record<string, string>;           // Vault env vars, injected into exec_command / input_command subprocesses
-  stripProxyEnv?: () => boolean;            // true = strip HTTP(S)_PROXY/ALL_PROXY (NO_PROXY kept) from command subprocesses; re-read per spawn, absent = proxy allowed
+  proxyEnv?: () => ProxyEnvPolicy | null;   // command-subprocess proxy policy; re-read per spawn, absent or null = pass through
 }
 
+// "strip" removes HTTP(S)_PROXY/ALL_PROXY (NO_PROXY kept); "inject" forces the explicit
+// proxy over the inherited env: HTTP(S)_PROXY (+ lowercase twins) = url, NO_PROXY = noProxy
+// (supplied pre-merged by the caller), inherited ALL_PROXY removed. Vault entries still win.
+type ProxyEnvPolicy = { mode: "strip" } | { mode: "inject"; url: string; noProxy: string };
+
 interface EnvironmentServices {
   subagentRunner?: SubagentRunner;          // needed by run_subagent
   visionDescriber?: VisionDescriberService; // needed by describe_image on text-only models
diff --git a/packages/docs/content/interfaces.zh.md b/packages/docs/content/interfaces.zh.md
index 0cdd614..376c637 100644
--- a/packages/docs/content/interfaces.zh.md
+++ b/packages/docs/content/interfaces.zh.md
@@ -127,9 +127,14 @@ interface EnvironmentConfig {
   sessionScratchpadDir?: string;            // 本 Session 的 scratchpad（scratchpad/<sessionId>），提供后启用截断输出恢复
   services?: EnvironmentServices;           // 注入给个别工具的运行时服务
   vault?: Record<string, string>;           // Vault 环境变量,注入 exec_command / input_command 子进程
-  stripProxyEnv?: () => boolean;            // 返回 true 时从命令子进程剥除 HTTP(S)_PROXY/ALL_PROXY（保留 NO_PROXY）；每次 spawn 重读，缺省即允许代理
+  proxyEnv?: () => ProxyEnvPolicy | null;   // 命令子进程代理策略；每次 spawn 重读，缺省或 null 即原样透传
 }
 
+// "strip" 剥除 HTTP(S)_PROXY/ALL_PROXY（保留 NO_PROXY）；"inject" 以显式代理覆盖继承环境：
+// HTTP(S)_PROXY（含小写拼写）= url、NO_PROXY = noProxy（由调用方预先合并），继承的 ALL_PROXY
+// 一并移除。Vault 条目仍然优先。
+type ProxyEnvPolicy = { mode: "strip" } | { mode: "inject"; url: string; noProxy: string };
+
 interface EnvironmentServices {
   subagentRunner?: SubagentRunner;          // run_subagent 所需
   visionDescriber?: VisionDescriberService; // text-only 模型的 describe_image 所需
diff --git a/packages/docs/content/server-api.en.md b/packages/docs/content/server-api.en.md
index a65faac..0ed34ea 100644
--- a/packages/docs/content/server-api.en.md
+++ b/packages/docs/content/server-api.en.md
@@ -73,10 +73,16 @@ In desktop mode (the server spawned by the desktop app) the whole surface answer
 
 | Method | Path | Description |
 | --- | --- | --- |
-| GET | /api/admin/settings | Server-global settings: `{settings: {useSystemProxy}}` |
+| GET | /api/admin/settings | Server-global settings: `{settings: {proxyForApp, proxyForAgent, proxyUrl}}` |
 | PUT | /api/admin/settings | Update settings (fields optional; omitted fields keep their current value), returns the full updated settings |
 
-`useSystemProxy` is the "use system HTTP proxy" switch (default on): while on, the server and its child processes honor HTTP_PROXY / HTTPS_PROXY / NO_PROXY (both spellings) for outbound traffic; while off, the server always connects directly and the proxy variables are stripped from agent command subprocess environments (NO_PROXY is kept). In either state the effective NO_PROXY always includes `localhost,127.0.0.1,::1` (loopback is never proxied). Toggling takes effect for newly initiated connections immediately — no restart.
+The proxy settings are two independent switches sharing one optional explicit address; changes take effect for newly initiated connections/spawns immediately — no restart:
+
+- `proxyForApp` ("application uses the proxy", default on) governs the server's own outbound traffic (LLM requests, the update check, image fetches): on with `proxyUrl` set → that address for both http and https, **taking precedence over the proxy environment variables** — no environment variable needs to be configured; on without an address → the environment variables HTTP_PROXY / HTTPS_PROXY / NO_PROXY (both spellings); off → always direct.
+- `proxyForAgent` ("agent environment uses the proxy", default on) governs agent command subprocess environments: on with `proxyUrl` set → `HTTP_PROXY` / `HTTPS_PROXY` (plus lowercase twins) are injected as that address together with the merged NO_PROXY, overriding inherited values; on without an address → the host environment passes through unchanged; off → the proxy variables are stripped (NO_PROXY is kept).
+- `proxyUrl` (default null = follow the environment variables) is the shared explicit address. Validation on PUT: the value is trimmed; empty or null clears the address; accepted forms are `http://host[:port]`, `https://host[:port]`, and bare `host[:port]` (normalized to `http://host[:port]` — only normalized values are stored, and the response echoes the stored form); anything else is `400` with code `invalid_proxy_url`, and the rejected PUT writes nothing.
+
+In every on-state the effective NO_PROXY always includes `localhost,127.0.0.1,::1` (loopback is never proxied).
 
 ### Version and Self-Update
 
diff --git a/packages/docs/content/server-api.zh.md b/packages/docs/content/server-api.zh.md
index c9b31eb..a913ab4 100644
--- a/packages/docs/content/server-api.zh.md
+++ b/packages/docs/content/server-api.zh.md
@@ -73,10 +73,16 @@ curl -c cookies.txt -H "Content-Type: application/json" \
 
 | 方法 | 路径 | 说明 |
 | --- | --- | --- |
-| GET | /api/admin/settings | 服务端全局设置：`{settings: {useSystemProxy}}` |
+| GET | /api/admin/settings | 服务端全局设置：`{settings: {proxyForApp, proxyForAgent, proxyUrl}}` |
 | PUT | /api/admin/settings | 更新设置（字段可省略，省略即保持现值），返回更新后的完整设置 |
 
-`useSystemProxy` 即「使用系统 HTTP 代理」开关（默认开）：开时服务端及其子进程出网遵循 HTTP_PROXY / HTTPS_PROXY / NO_PROXY（大小写并存）；关时服务端一律直连，并从 Agent 命令子进程环境中剥除代理变量（NO_PROXY 保留）。任一状态下生效的 NO_PROXY 恒包含 `localhost,127.0.0.1,::1`（回环不代理）。切换即时生效（对新发起的连接），无需重启。
+代理设置为两个独立开关共享一个可选的显式地址；修改即时生效（对新发起的连接与新派生的子进程），无需重启：
+
+- `proxyForApp`（「应用程序使用代理」，默认开）治理服务端自身出网（LLM 请求、更新检查、图片抓取）：开且填写了 `proxyUrl` → http 与 https 流量都走该地址，**优先于代理环境变量**——无需配置任何环境变量；开但未填地址 → 遵循 HTTP_PROXY / HTTPS_PROXY / NO_PROXY 环境变量（大小写并存）；关 → 一律直连。
+- `proxyForAgent`（「Agent 环境使用代理」，默认开）治理 Agent 命令子进程环境：开且填写了 `proxyUrl` → 注入 `HTTP_PROXY` / `HTTPS_PROXY`（含小写拼写）为该地址并附合并后的 NO_PROXY，覆盖继承值；开但未填地址 → 宿主环境原样透传；关 → 剥除代理变量（NO_PROXY 保留）。
+- `proxyUrl`（默认 null = 跟随环境变量）即两者共享的显式地址。PUT 校验：先 trim；空串或 null 即清除地址；接受 `http://主机[:端口]`、`https://主机[:端口]` 与裸 `主机[:端口]`（规范化为 `http://主机[:端口]`——只存储规范化后的值，响应回显存储形态）；其余一律 `400`，错误码 `invalid_proxy_url`，且被拒绝的 PUT 不写入任何字段。
+
+任一开启状态下生效的 NO_PROXY 恒包含 `localhost,127.0.0.1,::1`（回环不代理）。
 
 ### 版本与在线更新
 
diff --git a/packages/server/src/api/types.ts b/packages/server/src/api/types.ts
index d7b4551..e2f4990 100644
--- a/packages/server/src/api/types.ts
+++ b/packages/server/src/api/types.ts
@@ -64,8 +64,9 @@ export interface AuthResponse {
 export interface MeResponse {
   user: UserInfo;
   /**
-   * Whether Workspace HTML previews open on a separate origin (see design §
-   * "Workspace 文件预览"). False means this deployment has no usable preview origin —
+   * Whether Workspace HTML previews open on a separate origin (the loopback
+   * counterpart of the App host, or PENGUIN_PREVIEW_ORIGIN when set). False means this
+   * deployment has no usable preview origin —
    * the App is reached on something other than a loopback name and
    * PENGUIN_PREVIEW_ORIGIN is unset — so previews fall back to the same-origin sandbox,
    * where `localStorage`, cookies and third-party embeds do not work. Computed per
@@ -76,7 +77,7 @@ export interface MeResponse {
    * Whether this server runs in desktop mode (spawned by the desktop shell with
    * PENGUIN_DESKTOP_TOKEN). The web app then hides the logout entry, the
    * initial-password banner and the self-update entry, and omits the old-password
-   * field when changing the password. See design § "桌面端原型".
+   * field when changing the password.
    */
   desktopMode: boolean;
   /**
@@ -119,17 +120,35 @@ export interface AdminPasswordResetRequest {
   password: string;
 }
 
-/** Admin-level server-global settings (SQLite server_settings; design § "出网与系统代理"). */
+/**
+ * Admin-level server-global settings (SQLite server_settings):
+ * two independent proxy switches sharing one optional explicit address. In every
+ * on-state the effective NO_PROXY always includes localhost/127.0.0.1/::1 (loopback is
+ * never proxied), and changes apply to newly initiated connections/spawns immediately —
+ * no restart.
+ */
 export interface ServerSettings {
   /**
-   * "Use system HTTP proxy" (default on): whether the server process and its child
-   * processes reach the internet through the proxy named by HTTP_PROXY / HTTPS_PROXY
-   * (both spellings). Off = direct connections, with the proxy variables also stripped
-   * from agent command subprocess environments. Either way the effective NO_PROXY always
-   * includes localhost/127.0.0.1/::1 (loopback is never proxied). Toggling applies to
-   * newly initiated connections immediately — no restart.
+   * "Application uses the proxy" (default on): the server's own outbound traffic (LLM
+   * requests, the update check, image fetches). On with `proxyUrl` set = that address
+   * for both http and https; on without an address = the proxy environment variables
+   * HTTP_PROXY / HTTPS_PROXY (both spellings); off = always direct.
    */
-  useSystemProxy: boolean;
+  proxyForApp: boolean;
+  /**
+   * "Agent environment uses the proxy" (default on): agent command subprocess
+   * environments. On with `proxyUrl` set = HTTP_PROXY / HTTPS_PROXY (plus lowercase
+   * twins) injected as that address with the merged NO_PROXY, overriding inherited
+   * values; on without an address = the host environment passes through unchanged;
+   * off = the proxy variables are stripped (NO_PROXY kept).
+   */
+  proxyForAgent: boolean;
+  /**
+   * The shared explicit proxy address (canonical `http(s)://host[:port]`), or null =
+   * follow the proxy environment variables. When set it takes precedence over
+   * HTTP_PROXY / HTTPS_PROXY wherever the owning switch is on.
+   */
+  proxyUrl: string | null;
 }
 
 export interface ServerSettingsResponse {
@@ -138,7 +157,15 @@ export interface ServerSettingsResponse {
 
 /** PUT body: every field optional, omitted fields keep their current value (mirrors prefs). */
 export interface ServerSettingsUpdateRequest {
-  useSystemProxy?: boolean;
+  proxyForApp?: boolean;
+  proxyForAgent?: boolean;
+  /**
+   * New proxy address. Accepted forms: `http://host[:port]`, `https://host[:port]`, or
+   * bare `host[:port]` (normalized to `http://…` — only normalized values are stored,
+   * and the response echoes the stored form). Empty/whitespace-only or null clears the
+   * address (follow the environment variables); anything else is 400 `invalid_proxy_url`.
+   */
+  proxyUrl?: string | null;
 }
 
 /** User UI preferences (SQLite ui_prefs, free-form JSON; known keys declared here). */
@@ -700,7 +727,7 @@ export interface MessagesPageInfo {
   before?: string;
   /**
    * Outline turns (the Web conversation outline's entry rule) opened BEFORE this
-   * window: the client offsets its global `第 N 轮` numbering by this, so a partial
+   * window: the client offsets its global "round N" numbering by this, so a partial
    * window never mis-numbers. 0 when the window starts at the beginning.
    */
   earlierTurns: number;
diff --git a/packages/server/src/app.ts b/packages/server/src/app.ts
index bcbffef..97ce256 100644
--- a/packages/server/src/app.ts
+++ b/packages/server/src/app.ts
@@ -13,7 +13,9 @@ import { Hono } from "hono";
 import type { Context } from "hono";
 import { bodyLimit } from "hono/body-limit";
 import type { DatabaseSync } from "node:sqlite";
+import type { ProxyEnvPolicy } from "@prismshadow/penguin-core";
 import type { ServerConfig } from "./config.js";
+import { mergedNoProxy } from "./net/proxy.js";
 import { openDatabase } from "./db/database.js";
 import { AgentsRepo } from "./db/repos/agents.js";
 import { AuthSessionsRepo } from "./db/repos/auth-sessions.js";
@@ -95,7 +97,7 @@ export interface AppDeps {
   db: DatabaseSync;
   sessionsRepo: SessionsRepo;
   prefsRepo: UiPrefsRepo;
-  /** Admin-level server-global settings (currently the "use system HTTP proxy" switch). */
+  /** Admin-level server-global settings (currently the proxy switches and address). */
   serverSettingsRepo: ServerSettingsRepo;
   authService: AuthService;
   adminService: AdminService;
@@ -157,12 +159,20 @@ export function buildAppDeps(config: ServerConfig, overrides: BuildDepsOverrides
   const errorsRepo = new ErrorsRepo(db);
   const prefsRepo = new UiPrefsRepo(db);
   const serverSettingsRepo = new ServerSettingsRepo(db);
-  // Proxy-off also strips HTTP(S)_PROXY/ALL_PROXY from agent command subprocess
-  // environments (design § "出网与系统代理"). A getter, not a snapshot: it is re-read at
-  // every command spawn, so a toggle reaches already-loaded Sessions. Threaded through
-  // BOTH core entry paths — the loader (resume/self-heal) and SessionService (creation,
-  // whose runtime the manager adopts for the first Task).
-  const stripProxyEnv = () => !serverSettingsRepo.getUseSystemProxy();
+  // Command-subprocess proxy policy for core, keyed on the
+  // "agent environment uses the proxy" switch (the app switch only drives the server's
+  // own dispatcher, see net/proxy.ts): switch off → strip HTTP(S)_PROXY/ALL_PROXY; on
+  // with an explicit address → inject that address (with the merged loopback NO_PROXY)
+  // over whatever the environment carries; on without an address → pass the environment
+  // through. A getter, not a snapshot: it is re-read at every command spawn, so a
+  // settings change reaches already-loaded Sessions. Threaded through BOTH core entry
+  // paths — the loader (resume/self-heal) and SessionService (creation, whose runtime
+  // the manager adopts for the first Task).
+  const proxyEnv = (): ProxyEnvPolicy | null => {
+    if (!serverSettingsRepo.getProxyForAgent()) return { mode: "strip" };
+    const url = serverSettingsRepo.getProxyUrl();
+    return url === null ? null : { mode: "inject", url, noProxy: mergedNoProxy() };
+  };
   const schedulesRepo = new SchedulesRepo(db);
   const goalsRepo = new GoalsRepo(db);
 
@@ -214,8 +224,7 @@ export function buildAppDeps(config: ServerConfig, overrides: BuildDepsOverrides
   const manager = new SessionManager({
     sessions: sessionsRepo,
     channels,
-    loader:
-      overrides.loader ?? createCoreSessionLoader(config.root, sessionSources, { stripProxyEnv }),
+    loader: overrides.loader ?? createCoreSessionLoader(config.root, sessionSources, { proxyEnv }),
     sources: sessionSources,
     recorder,
     errors,
@@ -264,7 +273,7 @@ export function buildAppDeps(config: ServerConfig, overrides: BuildDepsOverrides
     projectConfig: projectConfigService,
     sources: sessionSources,
     traceIndex,
-    stripProxyEnv,
+    proxyEnv,
   });
   // Schedule scheduler: active only while the server is running. Only
   // assembled here; start() is called in index.ts (tests drive it via tickOnce, no real timer).
@@ -350,7 +359,7 @@ export function createApp(deps: AppDeps): Hono<AppEnv> {
   // cookie had ever been set on that host — act as the user. So the preview host serves ONLY
   // /preview/*: /api answers 401 (it never sets or honors a cookie there, closing both the
   // login and the stale-cookie paths), and everything else 302s to the canonical App host.
-  // See design § "Workspace 文件预览". Off when PENGUIN_PREVIEW_ORIGIN is set: previews then
+  // Off when PENGUIN_PREVIEW_ORIGIN is set: previews then
   // use that origin rather than the loopback counterpart, so 127.0.0.1 is an ordinary App
   // access point and must not be locked down — deployments enforce the equivalent at the
   // reverse proxy (route only /preview/* to the App on the preview origin).
@@ -428,7 +437,7 @@ export function createApp(deps: AppDeps): Hono<AppEnv> {
   // Workspace HTML preview on the separate preview origin: deliberately outside /api and
   // outside the auth middleware — that origin never receives the session cookie, so the
   // signed token in the path is the only credential. Mounted before static hosting so the
-  // SPA fallback cannot swallow it. See design § "Workspace 文件预览".
+  // SPA fallback cannot swallow it.
   app.route("/preview", previewRoutes(deps));
 
   // Static hosting (production): serves the frontend build output when webDist exists, with SPA fallback to index.html.
diff --git a/packages/server/src/db/repos/server-settings.ts b/packages/server/src/db/repos/server-settings.ts
index 4f13f91..3065315 100644
--- a/packages/server/src/db/repos/server-settings.ts
+++ b/packages/server/src/db/repos/server-settings.ts
@@ -5,8 +5,22 @@
  */
 import type { DatabaseSync } from "node:sqlite";
 
-/** Key of the "use system HTTP proxy" switch (design § "出网与系统代理"); default on. */
-const USE_SYSTEM_PROXY_KEY = "use_system_proxy";
+/** Key of the "application uses the proxy" switch (the server's own outbound dispatcher); default on. */
+const PROXY_FOR_APP_KEY = "proxy_for_app";
+
+/** Key of the "agent environment uses the proxy" switch (command subprocess env policy); default on. */
+const PROXY_FOR_AGENT_KEY = "proxy_for_agent";
+
+/**
+ * Legacy single-switch key from the unreleased #225 iteration (never in a release): read
+ * as the fallback default for BOTH new switches while their own keys are absent, so a
+ * main-branch deployment that had toggled it keeps its choice. Read-only adoption — the
+ * legacy key is never written back, and either new key, once set, wins for its switch.
+ */
+const LEGACY_USE_SYSTEM_PROXY_KEY = "use_system_proxy";
+
+/** Key of the explicit proxy address; absent/null = follow the proxy environment variables. */
+const PROXY_URL_KEY = "proxy_url";
 
 export class ServerSettingsRepo {
   constructor(private readonly db: DatabaseSync) {}
@@ -26,12 +40,48 @@ export class ServerSettingsRepo {
       .run(key, value);
   }
 
-  /** The "use system HTTP proxy" switch; an absent (or unreadable) row reads as the default: on. */
-  getUseSystemProxy(): boolean {
-    return this.get(USE_SYSTEM_PROXY_KEY) !== "false";
+  /** Shared switch read: this key if present, else the legacy single switch, else the default: on. */
+  private getProxySwitch(key: string): boolean {
+    const raw = this.get(key);
+    if (raw !== null) return raw !== "false";
+    return this.get(LEGACY_USE_SYSTEM_PROXY_KEY) !== "false";
   }
 
-  setUseSystemProxy(value: boolean): void {
-    this.set(USE_SYSTEM_PROXY_KEY, JSON.stringify(value));
+  /** The "application uses the proxy" switch (the server's own outbound dispatcher). */
+  getProxyForApp(): boolean {
+    return this.getProxySwitch(PROXY_FOR_APP_KEY);
+  }
+
+  setProxyForApp(value: boolean): void {
+    this.set(PROXY_FOR_APP_KEY, JSON.stringify(value));
+  }
+
+  /** The "agent environment uses the proxy" switch (command subprocess env policy). */
+  getProxyForAgent(): boolean {
+    return this.getProxySwitch(PROXY_FOR_AGENT_KEY);
+  }
+
+  setProxyForAgent(value: boolean): void {
+    this.set(PROXY_FOR_AGENT_KEY, JSON.stringify(value));
+  }
+
+  /**
+   * The explicit proxy address (normalized at write time by the settings route); null =
+   * follow the proxy environment variables. An absent or unreadable row reads as null
+   * (the safe default: behave as before the setting existed).
+   */
+  getProxyUrl(): string | null {
+    const raw = this.get(PROXY_URL_KEY);
+    if (raw === null) return null;
+    try {
+      const value: unknown = JSON.parse(raw);
+      return typeof value === "string" && value !== "" ? value : null;
+    } catch {
+      return null;
+    }
+  }
+
+  setProxyUrl(value: string | null): void {
+    this.set(PROXY_URL_KEY, JSON.stringify(value));
   }
 }
diff --git a/packages/server/src/db/schema.ts b/packages/server/src/db/schema.ts
index a1a0de7..d86a5ca 100644
--- a/packages/server/src/db/schema.ts
+++ b/packages/server/src/db/schema.ts
@@ -122,7 +122,7 @@ CREATE TABLE IF NOT EXISTS ui_prefs (
   prefs_json TEXT NOT NULL                    -- {theme?, lastProjectId?, ...} free-form JSON
 );
 CREATE TABLE IF NOT EXISTS server_settings (   -- admin-level server-global settings (GET/PUT /api/admin/settings)
-  key   TEXT PRIMARY KEY,                     -- setting name, e.g. 'use_system_proxy'
+  key   TEXT PRIMARY KEY,                     -- setting name, e.g. 'proxy_for_app'
   value TEXT NOT NULL                         -- JSON-encoded value; an absent row means the setting's built-in default
 );
 CREATE TABLE IF NOT EXISTS trace_files (       -- DERIVED CACHE of the on-disk Trace tree (services/trace-index.ts): the directories stay the single source of truth, every row is rebuildable from disk, and a row is never authority for absence — consumers reconcile + retry on a miss, so a stale index costs one extra scan, never a false 404
diff --git a/packages/server/src/http/routes/admin-settings.ts b/packages/server/src/http/routes/admin-settings.ts
index 4e6f602..e894109 100644
--- a/packages/server/src/http/routes/admin-settings.ts
+++ b/packages/server/src/http/routes/admin-settings.ts
@@ -1,9 +1,13 @@
 /**
  * Admin server-settings routes (admin only, 403 for non-admins):
  * GET|PUT /api/admin/settings — the server-global settings stored in server_settings
- * (currently the "use system HTTP proxy" switch, design § "出网与系统代理").
- * A PUT applies immediately: the persisted value is written first, then the process
- * dispatcher is rebuilt so new outbound connections follow the toggle without a restart.
+ * (currently the proxy settings: the "application uses the proxy" and "agent
+ * environment uses the proxy" switches and their shared explicit address).
+ * A PUT applies immediately: everything is validated first (a rejected request writes
+ * nothing), then the persisted values are written, then the process dispatcher is
+ * rebuilt so new outbound connections follow the change without a restart (the agent
+ * switch needs no push — the command-subprocess policy getter re-reads the repo at
+ * every spawn).
  */
 import { Hono } from "hono";
 import type { ServerSettingsResponse } from "../../api/types.js";
@@ -11,7 +15,26 @@ import { HttpError } from "../errors.js";
 import type { AppEnv } from "../../auth/middleware.js";
 import { optionalBoolean, readJson } from "../validate.js";
 import type { AppDeps } from "../../app.js";
-import { setUseSystemProxy } from "../../net/proxy.js";
+import { applyProxySettings, normalizeProxyUrl } from "../../net/proxy.js";
+
+/**
+ * proxyUrl update value -> stored value: null and empty/whitespace-only clear the
+ * address; anything else must normalize (see normalizeProxyUrl) or the whole PUT is
+ * rejected with `invalid_proxy_url` — un-normalized values are never stored.
+ */
+function parseProxyUrl(value: unknown): string | null {
+  if (value === null) return null;
+  if (typeof value === "string") {
+    if (value.trim() === "") return null;
+    const normalized = normalizeProxyUrl(value);
+    if (normalized !== null) return normalized;
+  }
+  throw new HttpError(
+    400,
+    "invalid_proxy_url",
+    "proxyUrl must be http://host[:port], https://host[:port], or host[:port] (empty or null clears it).",
+  );
+}
 
 export function adminSettingsRoutes(deps: AppDeps): Hono<AppEnv> {
   const app = new Hono<AppEnv>();
@@ -24,19 +47,32 @@ export function adminSettingsRoutes(deps: AppDeps): Hono<AppEnv> {
   });
 
   const settings = (): ServerSettingsResponse => ({
-    settings: { useSystemProxy: deps.serverSettingsRepo.getUseSystemProxy() },
+    settings: {
+      proxyForApp: deps.serverSettingsRepo.getProxyForApp(),
+      proxyForAgent: deps.serverSettingsRepo.getProxyForAgent(),
+      proxyUrl: deps.serverSettingsRepo.getProxyUrl(),
+    },
   });
 
   app.get("/", (c) => c.json(settings()));
 
   app.put("/", async (c) => {
     const body = await readJson(c);
-    const useSystemProxy = optionalBoolean(body, "useSystemProxy");
-    if (useSystemProxy !== undefined) {
-      deps.serverSettingsRepo.setUseSystemProxy(useSystemProxy);
-      // Mirror into the process: rebuilds the global fetch dispatcher (live toggle).
-      setUseSystemProxy(useSystemProxy);
-    }
+    // Validate every provided field before writing any: a partial PUT with one invalid
+    // field must leave the others untouched too.
+    const proxyForApp = optionalBoolean(body, "proxyForApp");
+    const proxyForAgent = optionalBoolean(body, "proxyForAgent");
+    const proxyUrlProvided = body.proxyUrl !== undefined;
+    const proxyUrl = proxyUrlProvided ? parseProxyUrl(body.proxyUrl) : null;
+    if (proxyForApp !== undefined) deps.serverSettingsRepo.setProxyForApp(proxyForApp);
+    if (proxyForAgent !== undefined) deps.serverSettingsRepo.setProxyForAgent(proxyForAgent);
+    if (proxyUrlProvided) deps.serverSettingsRepo.setProxyUrl(proxyUrl);
+    // Mirror the app switch + address into the process: rebuilds the global fetch
+    // dispatcher (live change, no restart; a no-op when nothing effectively changed).
+    applyProxySettings({
+      proxyForApp: deps.serverSettingsRepo.getProxyForApp(),
+      proxyUrl: deps.serverSettingsRepo.getProxyUrl(),
+    });
     return c.json(settings());
   });
 
diff --git a/packages/server/src/index.ts b/packages/server/src/index.ts
index 28abc63..dfcf52c 100644
--- a/packages/server/src/index.ts
+++ b/packages/server/src/index.ts
@@ -15,7 +15,7 @@ import { config as loadDotenv } from "dotenv";
 import { serve } from "@hono/node-server";
 import { buildAppDeps, createApp } from "./app.js";
 import { resolveServerConfig } from "./config.js";
-import { installGlobalProxyDispatcher, setUseSystemProxy } from "./net/proxy.js";
+import { applyProxySettings, installGlobalProxyDispatcher } from "./net/proxy.js";
 import { loopbackHostRoles } from "./services/preview-token.js";
 import { acquireServerLock, liveServerLock, releaseServerLock } from "./lock.js";
 
@@ -23,9 +23,10 @@ loadDotenv({ quiet: true });
 
 // Outbound proxy support, installed at the earliest point (right after dotenv, which may
 // itself define HTTP_PROXY): replaces globalThis.fetch with undici's and sets the global
-// dispatcher, starting from the switch default (on). The persisted value can only be
-// read once the database is open, so it is applied via setUseSystemProxy right after
-// buildAppDeps below — nothing in between makes an outbound request. See net/proxy.ts.
+// dispatcher, starting from the defaults (app switch on, no explicit address). The
+// persisted values can only be read once the database is open, so they are applied via
+// applyProxySettings right after buildAppDeps below — nothing in between makes an
+// outbound request. See net/proxy.ts.
 installGlobalProxyDispatcher();
 
 /** Exit code for "another server already owns this data root" (see lock.ts). */
@@ -47,10 +48,14 @@ if (existingLock) {
 }
 
 const deps = buildAppDeps(config);
-// The database is open now: bring the dispatcher in line with the persisted
-// "use system HTTP proxy" switch (an absent row reads as the default: on) before the
-// first possible outbound request (update check, LLM calls — all behind HTTP handlers).
-setUseSystemProxy(deps.serverSettingsRepo.getUseSystemProxy());
+// The database is open now: bring the dispatcher in line with the persisted proxy
+// settings (absent rows read as the defaults: app switch on, no explicit address)
+// before the first possible outbound request (update check, LLM calls — all behind
+// HTTP handlers).
+applyProxySettings({
+  proxyForApp: deps.serverSettingsRepo.getProxyForApp(),
+  proxyUrl: deps.serverSettingsRepo.getProxyUrl(),
+});
 const app = createApp(deps);
 
 // Built-in admin seed (idempotent): creates admin and adopts default_project when the
@@ -84,7 +89,7 @@ const appHost = loopbackHostRoles(config.host)?.app ?? config.host;
  * Second loopback listener so the preview origin is actually reachable.
  *
  * Workspace HTML previews are served from the loopback counterpart of the host the App
- * is used on (`127.0.0.1` <-> `localhost`, see design § "Workspace 文件预览"). On most
+ * is used on (`127.0.0.1` <-> `localhost`). On most
  * systems `localhost` resolves to `::1` first, so a server bound only to `127.0.0.1`
  * would leave every preview URL refusing connections. Binding `::1` as well closes that
  * gap. Failure is non-fatal — the App keeps working, previews just fall back.
diff --git a/packages/server/src/net/proxy.ts b/packages/server/src/net/proxy.ts
index 689a7ac..75fca26 100644
--- a/packages/server/src/net/proxy.ts
+++ b/packages/server/src/net/proxy.ts
@@ -1,29 +1,39 @@
 /**
- * Outbound networking and the "use system HTTP proxy" switch (design § "出网与系统代理").
+ * Outbound networking and the admin proxy settings.
  *
  * Node 24's built-in fetch does not read the proxy environment variables
  * (NODE_USE_ENV_PROXY is ineffective on 24.18), so the server routes ALL of its own
  * outbound traffic through undici: the startup entry replaces `globalThis.fetch` with
  * undici's fetch once, and this module keeps undici's global dispatcher in line with the
- * admin-level setting — undici's fetch resolves the global dispatcher per call, so a
- * toggle takes effect for newly initiated connections without a restart.
+ * admin-level settings — undici's fetch resolves the global dispatcher per call, so a
+ * settings change takes effect for newly initiated connections without a restart.
  *
- * Dispatcher per setting:
- *   - on (default): `EnvHttpProxyAgent` — honors HTTP_PROXY / HTTPS_PROXY (both
- *     spellings; undici reads the lowercase name first) with a NO_PROXY list merged from
- *     the environment plus the loopback names;
- *   - off: a plain `Agent` — direct connections, proxy variables ignored.
+ * Dispatcher per settings state (keyed on the "application uses the proxy" switch; the
+ * separate agent-environment switch never touches the dispatcher — it only drives the
+ * command-subprocess policy in app.ts):
+ *   - app switch off: a plain `Agent` — direct connections, proxy variables ignored;
+ *   - on, no explicit address (default): `EnvHttpProxyAgent` — honors HTTP_PROXY /
+ *     HTTPS_PROXY (both spellings; undici reads the lowercase name first) with a
+ *     NO_PROXY list merged from the environment plus the loopback names;
+ *   - on with an explicit address (`proxyUrl`): `EnvHttpProxyAgent` again, but with its
+ *     `httpProxy` / `httpsProxy` options pinned to that URL — undici consults those
+ *     BEFORE the environment (verified against undici 7.29's constructor:
+ *     `httpProxy ?? process.env.http_proxy ?? process.env.HTTP_PROXY`), so the explicit
+ *     address governs both http and https traffic regardless of ambient env, while the
+ *     merged NO_PROXY keeps working through the same `noProxy` option.
  *
- * The loopback merge is load-bearing in either state: the CLI's readiness probe
+ * The loopback merge is load-bearing in every state: the CLI's readiness probe
  * (`penguin web` imports the server in-process and polls its own root path), SSE, and
  * Workspace previews all ride the loopback names, so a proxy that intercepts loopback
  * would take the whole App down. `localhost,127.0.0.1,::1` is therefore ALWAYS appended
  * to the effective NO_PROXY, regardless of what the environment declares.
  *
- * The value persisted in server_settings stays authoritative (the routes read/write the
- * repo); this module only mirrors it into the process-global dispatcher. Stripping the
- * proxy variables from agent command subprocesses when the switch is off lives in core
- * (CommandSessionManager, threaded through the session loader), not here.
+ * The values persisted in server_settings stay authoritative (the routes read/write the
+ * repo); this module only mirrors them into the process-global dispatcher. The command
+ * subprocess side — keyed on the agent-environment switch: strip the proxy variables
+ * when it is off, inject the explicit address when set, pass through otherwise — lives
+ * in core (CommandSessionManager, threaded through the session loader as a
+ * ProxyEnvPolicy getter), not here.
  */
 import { Agent, EnvHttpProxyAgent, fetch as undiciFetch, setGlobalDispatcher } from "undici";
 import type { Dispatcher } from "undici";
@@ -31,10 +41,19 @@ import type { Dispatcher } from "undici";
 /** Loopback names every effective NO_PROXY must contain (see module doc). */
 export const LOOPBACK_NO_PROXY = ["localhost", "127.0.0.1", "::1"] as const;
 
+/** The slice of the admin proxy settings the dispatcher mirrors (persisted in server_settings). */
+export interface ProxySettings {
+  /** The "application uses the proxy" switch (default on). */
+  proxyForApp: boolean;
+  /** Explicit proxy URL (normalized, see {@link normalizeProxyUrl}); null = follow the proxy environment variables. */
+  proxyUrl: string | null;
+}
+
 /**
  * The effective NO_PROXY: the environment's entries (lowercase spelling first, matching
  * undici's own precedence) with the loopback names appended when missing. Exported as a
- * pure helper for tests; `env` defaults to the real process environment.
+ * pure helper for tests and for app.ts's command-subprocess policy getter; `env`
+ * defaults to the real process environment.
  */
 export function mergedNoProxy(env: NodeJS.ProcessEnv = process.env): string {
   const raw = env.no_proxy ?? env.NO_PROXY ?? "";
@@ -48,49 +67,100 @@ export function mergedNoProxy(env: NodeJS.ProcessEnv = process.env): string {
 }
 
 /**
- * Builds the global dispatcher for a switch state (pure choice, exported for tests):
- * on → EnvHttpProxyAgent with the merged NO_PROXY, off → direct-connect Agent.
+ * Normalizes a proxy address to its canonical URL, or null when it is not acceptable.
+ * Accepted forms: `http://host[:port]`, `https://host[:port]`, and the bare
+ * `host[:port]` / `host` shorthand (normalized to `http://…`). Anything else — other
+ * schemes (the dispatcher speaks only HTTP(S) proxies; a socks:// URL would break every
+ * server fetch, see os-proxy.ts for the same rule), credentials, paths, queries — is
+ * rejected rather than stored: server_settings only ever holds normalized values.
  */
-export function buildProxyDispatcher(useSystemProxy: boolean, env?: NodeJS.ProcessEnv): Dispatcher {
-  // The merged list is passed via opts.noProxy, which REPLACES the environment lookup
-  // inside EnvHttpProxyAgent — merging is this module's job (undici would otherwise use
-  // env NO_PROXY verbatim, without the loopback exemption).
-  return useSystemProxy ? new EnvHttpProxyAgent({ noProxy: mergedNoProxy(env) }) : new Agent();
+export function normalizeProxyUrl(raw: string): string | null {
+  const trimmed = raw.trim();
+  if (trimmed === "") return null;
+  // Bare host[:port] shorthand: no scheme -> http. The scheme test requires "://", so
+  // "host:8080" (a port, not a scheme) takes the shorthand path.
+  const candidate = /^[a-zA-Z][a-zA-Z0-9+.-]*:\/\//.test(trimmed) ? trimmed : `http://${trimmed}`;
+  let url: URL;
+  try {
+    url = new URL(candidate);
+  } catch {
+    return null;
+  }
+  if (url.protocol !== "http:" && url.protocol !== "https:") return null;
+  if (url.hostname === "" || url.username !== "" || url.password !== "") return null;
+  // A proxy address is host-only; the parser's bare "/" (its normal form for an absent
+  // path) is tolerated, an actual path/query/fragment means this was not a proxy address.
+  if ((url.pathname !== "/" && url.pathname !== "") || url.search !== "" || url.hash !== "") {
+    return null;
+  }
+  // origin is the canonical form: lowercased scheme/host, default ports dropped.
+  return url.origin;
 }
 
-/** Current switch state mirrored for the dispatcher (the DB row is the persisted truth). */
-let useSystemProxy = true;
+/** The EnvHttpProxyAgent option subset this module assembles (undici's Options type is not re-exported cleanly). */
+export interface EnvProxyAgentOptions {
+  httpProxy?: string;
+  httpsProxy?: string;
+  noProxy: string;
+}
+
+/**
+ * The EnvHttpProxyAgent options for the switch-on states (pure choice, exported for
+ * tests): always the merged NO_PROXY — passed via opts.noProxy, which REPLACES the
+ * environment lookup inside EnvHttpProxyAgent, so merging is this module's job (undici
+ * would otherwise use env NO_PROXY verbatim, without the loopback exemption) — plus,
+ * with an explicit address, the httpProxy/httpsProxy overrides that pin both traffic
+ * kinds to it.
+ */
+export function envProxyAgentOptions(
+  proxyUrl: string | null,
+  env?: NodeJS.ProcessEnv,
+): EnvProxyAgentOptions {
+  const noProxy = mergedNoProxy(env);
+  return proxyUrl === null ? { noProxy } : { httpProxy: proxyUrl, httpsProxy: proxyUrl, noProxy };
+}
+
+/**
+ * Builds the global dispatcher for a settings state (pure choice, exported for tests):
+ * app switch off → direct-connect Agent, on → EnvHttpProxyAgent (env-driven, or pinned
+ * to the explicit address; see {@link envProxyAgentOptions}).
+ */
+export function buildProxyDispatcher(settings: ProxySettings, env?: NodeJS.ProcessEnv): Dispatcher {
+  if (!settings.proxyForApp) return new Agent();
+  return new EnvHttpProxyAgent(envProxyAgentOptions(settings.proxyUrl, env));
+}
+
+/** Current settings mirrored for the dispatcher (the DB rows are the persisted truth). */
+let current: ProxySettings = { proxyForApp: true, proxyUrl: null };
 /** True once the startup entry has installed undici globally (never in tests). */
 let installed = false;
 
 /**
  * One-time install at the startup entry (index.ts), before anything can fetch: replaces
  * `globalThis.fetch` with undici's and sets the initial dispatcher. Starts from the
- * default (on) — the entry applies the persisted value via {@link setUseSystemProxy} as
- * soon as the database is open, before any outbound request exists. Tests never call
- * this, so they keep the runtime's own fetch (and their fetch stubs).
+ * defaults (on, no explicit address) — the entry applies the persisted values via
+ * {@link applyProxySettings} as soon as the database is open, before any outbound
+ * request exists. Tests never call this, so they keep the runtime's own fetch (and
+ * their fetch stubs).
  */
 export function installGlobalProxyDispatcher(): void {
   installed = true;
-  setGlobalDispatcher(buildProxyDispatcher(useSystemProxy));
+  setGlobalDispatcher(buildProxyDispatcher(current));
   // Cast: undici's fetch is typed against its own RequestInit/Response declarations,
   // which are structurally compatible with the runtime globals for every caller here.
   globalThis.fetch = undiciFetch as unknown as typeof globalThis.fetch;
 }
 
 /**
- * Applies a switch state to the process: rebuilds the global dispatcher so new
+ * Applies a settings state to the process: rebuilds the global dispatcher so new
  * connections follow it immediately (no restart). Called by the startup entry with the
- * persisted value and by PUT /api/admin/settings on every toggle. Outside the installed
- * runtime (tests) it only records the state.
+ * persisted values and by PUT /api/admin/settings on every change. Outside the
+ * installed runtime (tests) it only records the state.
  */
-export function setUseSystemProxy(value: boolean): void {
-  if (value === useSystemProxy) return;
-  useSystemProxy = value;
-  if (installed) setGlobalDispatcher(buildProxyDispatcher(useSystemProxy));
-}
-
-/** The switch state the dispatcher currently reflects. */
-export function getUseSystemProxy(): boolean {
-  return useSystemProxy;
+export function applyProxySettings(settings: ProxySettings): void {
+  if (settings.proxyForApp === current.proxyForApp && settings.proxyUrl === current.proxyUrl) {
+    return;
+  }
+  current = { proxyForApp: settings.proxyForApp, proxyUrl: settings.proxyUrl };
+  if (installed) setGlobalDispatcher(buildProxyDispatcher(current));
 }
diff --git a/packages/server/src/runtime/session-manager.ts b/packages/server/src/runtime/session-manager.ts
index f3352ba..06116d8 100644
--- a/packages/server/src/runtime/session-manager.ts
+++ b/packages/server/src/runtime/session-manager.ts
@@ -42,6 +42,7 @@ import type {
   ApproveFn,
   CompactAvailability,
   OmniMessage,
+  ProxyEnvPolicy,
   SessionMetaPayload,
   SessionTitleResult,
   TextPayload,
@@ -121,13 +122,14 @@ export interface SessionLoader {
  * lets the no-Trace self-heal rebuild re-record a known origin into the fresh session_meta;
  * with no registry entry (e.g. the process restarted and no Trace was ever written) the
  * rebuilt Session is unsourced — session_meta is the single source of truth, and none survived.
- * `opts.stripProxyEnv` threads the "use system HTTP proxy" switch into core (a live getter:
- * true = strip HTTP(S)_PROXY/ALL_PROXY from agent command subprocess environments).
+ * `opts.proxyEnv` threads the admin proxy settings into core (a live getter returning the
+ * agent-command-subprocess policy: strip the proxy variables, inject the explicit proxy
+ * address, or null = pass the environment through).
  */
 export function createCoreSessionLoader(
   root: string,
   sources?: SessionSources,
-  opts: { stripProxyEnv?: () => boolean } = {},
+  opts: { proxyEnv?: () => ProxyEnvPolicy | null } = {},
 ): SessionLoader {
   return {
     async load(row: SessionRow): Promise<RuntimeSession> {
@@ -135,7 +137,7 @@ export function createCoreSessionLoader(
         root,
         projectId: row.projectId,
         agentId: row.agentId,
-        ...(opts.stripProxyEnv ? { stripProxyEnv: opts.stripProxyEnv } : {}),
+        ...(opts.proxyEnv ? { proxyEnv: opts.proxyEnv } : {}),
       });
       const located = await findLatestTraceFile(
         tracesDir(root, row.projectId, row.agentId),
diff --git a/packages/server/src/services/session-service.ts b/packages/server/src/services/session-service.ts
index a0baff9..46203d4 100644
--- a/packages/server/src/services/session-service.ts
+++ b/packages/server/src/services/session-service.ts
@@ -15,6 +15,7 @@
  * added to session-manager's active table (state idle).
  */
 import { createAgent, isSessionMeta } from "@prismshadow/penguin-core";
+import type { ProxyEnvPolicy } from "@prismshadow/penguin-core";
 import type {
   ApprovalMode,
   SessionCategory,
@@ -52,11 +53,11 @@ export interface SessionServiceDeps {
   /** Trace-file index: discovery / adoption / stats serve from it (mtime-gated reconciler; no per-request walks). */
   traceIndex: TraceIndexService;
   /**
-   * "Use system HTTP proxy" switch threading (same getter the session loader passes,
-   * see createCoreSessionLoader): the runtime created here is adopted by the manager
-   * and runs the Session's first Task, so it needs the strip policy too.
+   * Admin proxy-settings threading (same getter the session loader passes, see
+   * createCoreSessionLoader): the runtime created here is adopted by the manager and
+   * runs the Session's first Task, so it needs the command-subprocess proxy policy too.
    */
-  stripProxyEnv?: () => boolean;
+  proxyEnv?: () => ProxyEnvPolicy | null;
 }
 
 export class SessionService {
@@ -325,7 +326,7 @@ export class SessionService {
       root: this.deps.root,
       projectId: args.projectId,
       agentId: args.agentId,
-      ...(this.deps.stripProxyEnv ? { stripProxyEnv: this.deps.stripProxyEnv } : {}),
+      ...(this.deps.proxyEnv ? { proxyEnv: this.deps.proxyEnv } : {}),
     });
     let session;
     try {
diff --git a/packages/server/test/admin-settings.test.ts b/packages/server/test/admin-settings.test.ts
index a26da88..9ae3f61 100644
--- a/packages/server/test/admin-settings.test.ts
+++ b/packages/server/test/admin-settings.test.ts
@@ -1,7 +1,9 @@
 /**
- * Admin server-settings route tests: permission boundary (non-admin 403), the
- * "use system HTTP proxy" default (absent row reads as on), PUT persistence and
- * validation, and merge semantics (an omitted field keeps its current value).
+ * Admin server-settings route tests: permission boundary (non-admin 403), the proxy
+ * defaults (absent rows read as both switches on, no explicit address), adoption of the
+ * legacy single-switch key, PUT persistence and validation (proxy-address normalization
+ * and rejection), and merge semantics (an omitted field keeps its current value; a
+ * rejected PUT writes nothing).
  */
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
 import type { ServerSettingsResponse } from "../src/api/types.js";
@@ -30,39 +32,135 @@ describe("admin server settings", () => {
     const { cookie } = await provisionUser(t.app, "norm");
     const api = apiClient(t.app, cookie);
     expect((await api.get("/api/admin/settings")).status).toBe(403);
-    expect((await api.put("/api/admin/settings", { useSystemProxy: false })).status).toBe(403);
+    expect((await api.put("/api/admin/settings", { proxyForApp: false })).status).toBe(403);
     // The failed PUT changed nothing.
-    expect((await getSettings()).settings.useSystemProxy).toBe(true);
+    expect((await getSettings()).settings.proxyForApp).toBe(true);
   });
 
-  it("useSystemProxy defaults to on while no row exists", async () => {
+  it("defaults while no rows exist: both switches on, no explicit address", async () => {
     expect(t.deps.db.prepare("SELECT COUNT(*) AS n FROM server_settings").get()).toMatchObject({
       n: 0,
     });
-    expect((await getSettings()).settings.useSystemProxy).toBe(true);
+    const { settings } = await getSettings();
+    expect(settings.proxyForApp).toBe(true);
+    expect(settings.proxyForAgent).toBe(true);
+    expect(settings.proxyUrl).toBeNull();
   });
 
-  it("PUT persists the toggle and echoes the full settings", async () => {
-    const off = await admin.put("/api/admin/settings", { useSystemProxy: false });
-    expect(off.status).toBe(200);
-    expect(((await off.json()) as ServerSettingsResponse).settings.useSystemProxy).toBe(false);
-    // Round-trips through the repo (the DB row, not process state, is what GET serves).
-    expect((await getSettings()).settings.useSystemProxy).toBe(false);
-    expect(t.deps.serverSettingsRepo.getUseSystemProxy()).toBe(false);
+  it("adopts the legacy use_system_proxy row as the default for BOTH switches", async () => {
+    // The single switch shipped only on unreleased main (#225): a deployment that had
+    // toggled it off must keep that choice for both new switches, with no migration —
+    // the legacy key is read as a fallback, never rewritten.
+    t.deps.serverSettingsRepo.set("use_system_proxy", "false");
+    let { settings } = await getSettings();
+    expect(settings.proxyForApp).toBe(false);
+    expect(settings.proxyForAgent).toBe(false);
+    // Setting one NEW switch writes only its own key: the other still follows legacy.
+    await admin.put("/api/admin/settings", { proxyForApp: true });
+    ({ settings } = await getSettings());
+    expect(settings.proxyForApp).toBe(true);
+    expect(settings.proxyForAgent).toBe(false);
+    // The legacy row itself was never touched.
+    expect(t.deps.serverSettingsRepo.get("use_system_proxy")).toBe("false");
+  });
 
-    const on = await admin.put("/api/admin/settings", { useSystemProxy: true });
-    expect(on.status).toBe(200);
-    expect((await getSettings()).settings.useSystemProxy).toBe(true);
+  it("PUT persists the switches independently and echoes the full settings", async () => {
+    const appOff = await admin.put("/api/admin/settings", { proxyForApp: false });
+    expect(appOff.status).toBe(200);
+    const afterAppOff = ((await appOff.json()) as ServerSettingsResponse).settings;
+    expect(afterAppOff.proxyForApp).toBe(false);
+    expect(afterAppOff.proxyForAgent).toBe(true);
+    // Round-trips through the repo (the DB rows, not process state, are what GET serves).
+    expect(t.deps.serverSettingsRepo.getProxyForApp()).toBe(false);
+    expect(t.deps.serverSettingsRepo.getProxyForAgent()).toBe(true);
+
+    const agentOff = await admin.put("/api/admin/settings", { proxyForAgent: false });
+    expect(agentOff.status).toBe(200);
+    const { settings } = await getSettings();
+    expect(settings.proxyForApp).toBe(false);
+    expect(settings.proxyForAgent).toBe(false);
   });
 
   it("an omitted field keeps its current value; a non-boolean is 400", async () => {
-    await admin.put("/api/admin/settings", { useSystemProxy: false });
+    await admin.put("/api/admin/settings", { proxyForApp: false });
     // Empty PUT: no-op, still returns the current settings.
     const noop = await admin.put("/api/admin/settings", {});
     expect(noop.status).toBe(200);
-    expect(((await noop.json()) as ServerSettingsResponse).settings.useSystemProxy).toBe(false);
+    expect(((await noop.json()) as ServerSettingsResponse).settings.proxyForApp).toBe(false);
     // Type check: only booleans are accepted, and a rejected write changes nothing.
-    expect((await admin.put("/api/admin/settings", { useSystemProxy: "on" })).status).toBe(400);
-    expect((await getSettings()).settings.useSystemProxy).toBe(false);
+    expect((await admin.put("/api/admin/settings", { proxyForApp: "on" })).status).toBe(400);
+    expect((await admin.put("/api/admin/settings", { proxyForAgent: 1 })).status).toBe(400);
+    const { settings } = await getSettings();
+    expect(settings.proxyForApp).toBe(false);
+    expect(settings.proxyForAgent).toBe(true);
+  });
+
+  const putProxyUrl = async (proxyUrl: unknown) => admin.put("/api/admin/settings", { proxyUrl });
+
+  it("PUT normalizes the proxy address and stores/echoes only the normalized form", async () => {
+    // Bare host[:port] shorthand → http://.
+    const bare = await putProxyUrl("proxy.corp.example:8080");
+    expect(bare.status).toBe(200);
+    expect(((await bare.json()) as ServerSettingsResponse).settings.proxyUrl).toBe(
+      "http://proxy.corp.example:8080",
+    );
+    expect((await getSettings()).settings.proxyUrl).toBe("http://proxy.corp.example:8080");
+    expect(t.deps.serverSettingsRepo.getProxyUrl()).toBe("http://proxy.corp.example:8080");
+    // https passes through; surrounding whitespace is trimmed.
+    const https = await putProxyUrl("  https://proxy.corp.example:3128  ");
+    expect(https.status).toBe(200);
+    expect(((await https.json()) as ServerSettingsResponse).settings.proxyUrl).toBe(
+      "https://proxy.corp.example:3128",
+    );
+  });
+
+  it("PUT rejects a bad proxy address with invalid_proxy_url and stores nothing", async () => {
+    await putProxyUrl("http://proxy.corp.example:8080");
+    for (const bad of ["socks5://proxy.corp.example:1080", "not a proxy", 42]) {
+      const res = await putProxyUrl(bad);
+      expect(res.status).toBe(400);
+      const body = (await res.json()) as { error: { code: string } };
+      expect(body.error.code).toBe("invalid_proxy_url");
+    }
+    expect((await getSettings()).settings.proxyUrl).toBe("http://proxy.corp.example:8080");
+  });
+
+  it("a rejected combined PUT leaves the other fields untouched too", async () => {
+    // Validation happens before any write: the valid switch halves of a PUT whose
+    // proxyUrl is garbage must not land either — the PUT is atomic.
+    const res = await admin.put("/api/admin/settings", {
+      proxyForApp: false,
+      proxyForAgent: false,
+      proxyUrl: "not a proxy",
+    });
+    expect(res.status).toBe(400);
+    const { settings } = await getSettings();
+    expect(settings.proxyForApp).toBe(true);
+    expect(settings.proxyForAgent).toBe(true);
+    expect(settings.proxyUrl).toBeNull();
+  });
+
+  it("empty string and null both clear the address back to follow-the-environment", async () => {
+    for (const clear of ["", "   ", null]) {
+      await putProxyUrl("http://proxy.corp.example:8080");
+      const res = await putProxyUrl(clear);
+      expect(res.status).toBe(200);
+      expect(((await res.json()) as ServerSettingsResponse).settings.proxyUrl).toBeNull();
+      expect(t.deps.serverSettingsRepo.getProxyUrl()).toBeNull();
+    }
+  });
+
+  it("partial PUTs keep the other fields: address-only keeps the switches and vice versa", async () => {
+    await admin.put("/api/admin/settings", { proxyForApp: false, proxyForAgent: false });
+    await putProxyUrl("proxy.corp.example:8080");
+    let { settings } = await getSettings();
+    expect(settings.proxyForApp).toBe(false);
+    expect(settings.proxyForAgent).toBe(false);
+    expect(settings.proxyUrl).toBe("http://proxy.corp.example:8080");
+    await admin.put("/api/admin/settings", { proxyForApp: true, proxyForAgent: true });
+    ({ settings } = await getSettings());
+    expect(settings.proxyForApp).toBe(true);
+    expect(settings.proxyForAgent).toBe(true);
+    expect(settings.proxyUrl).toBe("http://proxy.corp.example:8080");
   });
 });
diff --git a/packages/server/test/proxy.test.ts b/packages/server/test/proxy.test.ts
index 5396099..b34461e 100644
--- a/packages/server/test/proxy.test.ts
+++ b/packages/server/test/proxy.test.ts
@@ -1,11 +1,20 @@
 /**
- * Unit tests for the outbound-proxy module's pure parts: the NO_PROXY loopback merge
- * and the dispatcher choice per switch state. No real network and no global install —
- * installGlobalProxyDispatcher (fetch replacement) runs only in the production entry.
+ * Unit tests for the outbound-proxy module's pure parts — the NO_PROXY loopback merge,
+ * proxy-address normalization, and the dispatcher choice per settings state — plus one
+ * behavioral check that an explicit address actually routes traffic through that proxy
+ * while loopback stays direct. No global install — installGlobalProxyDispatcher (fetch
+ * replacement) runs only in the production entry.
  */
+import http from "node:http";
+import type { AddressInfo } from "node:net";
 import { describe, expect, it } from "vitest";
-import { Agent, EnvHttpProxyAgent } from "undici";
-import { buildProxyDispatcher, mergedNoProxy } from "../src/net/proxy.js";
+import { Agent, EnvHttpProxyAgent, fetch as undiciFetch } from "undici";
+import {
+  buildProxyDispatcher,
+  envProxyAgentOptions,
+  mergedNoProxy,
+  normalizeProxyUrl,
+} from "../src/net/proxy.js";
 
 describe("mergedNoProxy", () => {
   it("yields exactly the loopback names when the environment has no NO_PROXY", () => {
@@ -35,17 +44,147 @@ describe("mergedNoProxy", () => {
   });
 });
 
+describe("normalizeProxyUrl", () => {
+  it("passes canonical http/https addresses through", () => {
+    expect(normalizeProxyUrl("http://proxy.corp.example:8080")).toBe(
+      "http://proxy.corp.example:8080",
+    );
+    expect(normalizeProxyUrl("https://proxy.corp.example:3128")).toBe(
+      "https://proxy.corp.example:3128",
+    );
+    expect(normalizeProxyUrl("http://proxy.corp.example")).toBe("http://proxy.corp.example");
+  });
+
+  it("normalizes the bare host[:port] shorthand to http://", () => {
+    expect(normalizeProxyUrl("proxy.corp.example:8080")).toBe("http://proxy.corp.example:8080");
+    expect(normalizeProxyUrl("proxy.corp.example")).toBe("http://proxy.corp.example");
+    expect(normalizeProxyUrl("127.0.0.1:7890")).toBe("http://127.0.0.1:7890");
+  });
+
+  it("canonicalizes case, surrounding whitespace, trailing slash, and default ports", () => {
+    expect(normalizeProxyUrl("  http://proxy.corp.example:8080  ")).toBe(
+      "http://proxy.corp.example:8080",
+    );
+    expect(normalizeProxyUrl("HTTP://PROXY.CORP.EXAMPLE:8080")).toBe(
+      "http://proxy.corp.example:8080",
+    );
+    expect(normalizeProxyUrl("http://proxy.corp.example:8080/")).toBe(
+      "http://proxy.corp.example:8080",
+    );
+    // URL's canonical form drops a scheme-default port; the connection is identical.
+    expect(normalizeProxyUrl("http://proxy.corp.example:80")).toBe("http://proxy.corp.example");
+  });
+
+  it("keeps IPv6 literals bracketed", () => {
+    expect(normalizeProxyUrl("http://[::1]:8080")).toBe("http://[::1]:8080");
+  });
+
+  it("rejects everything that is not an http(s) host[:port]", () => {
+    // Other schemes: the dispatcher speaks only HTTP(S) proxies.
+    expect(normalizeProxyUrl("socks5://proxy.corp.example:1080")).toBeNull();
+    expect(normalizeProxyUrl("ftp://proxy.corp.example")).toBeNull();
+    // Credentials, paths, queries, fragments: a proxy address is host-only.
+    expect(normalizeProxyUrl("http://user:pass@proxy.corp.example:8080")).toBeNull();
+    expect(normalizeProxyUrl("http://proxy.corp.example:8080/path")).toBeNull();
+    expect(normalizeProxyUrl("http://proxy.corp.example:8080?x=1")).toBeNull();
+    expect(normalizeProxyUrl("http://proxy.corp.example:8080#frag")).toBeNull();
+    // Unparseable shapes.
+    expect(normalizeProxyUrl("http://")).toBeNull();
+    expect(normalizeProxyUrl("not a proxy")).toBeNull();
+    expect(normalizeProxyUrl("proxy.corp.example:port")).toBeNull();
+    expect(normalizeProxyUrl("")).toBeNull();
+    expect(normalizeProxyUrl("   ")).toBeNull();
+  });
+});
+
+describe("envProxyAgentOptions", () => {
+  it("without an explicit address: only the merged NO_PROXY (env drives the proxies)", () => {
+    expect(envProxyAgentOptions(null, { NO_PROXY: "corp.example" })).toEqual({
+      noProxy: "corp.example,localhost,127.0.0.1,::1",
+    });
+  });
+
+  it("with an explicit address: both httpProxy and httpsProxy pinned to it, NO_PROXY still merged", () => {
+    // httpProxy/httpsProxy take precedence over the environment inside undici's
+    // EnvHttpProxyAgent (its constructor reads `httpProxy ?? env...`), so the ambient
+    // variables in `env` must not leak into the options this module assembles.
+    expect(
+      envProxyAgentOptions("http://explicit.example:3128", {
+        HTTP_PROXY: "http://ambient.example:8080",
+        NO_PROXY: "corp.example",
+      }),
+    ).toEqual({
+      httpProxy: "http://explicit.example:3128",
+      httpsProxy: "http://explicit.example:3128",
+      noProxy: "corp.example,localhost,127.0.0.1,::1",
+    });
+  });
+});
+
 describe("buildProxyDispatcher", () => {
-  it("on → EnvHttpProxyAgent (proxy env honored), off → plain Agent (direct)", async () => {
-    const on = buildProxyDispatcher(true, {});
-    const off = buildProxyDispatcher(false, {});
+  it("app switch off → plain Agent; on → EnvHttpProxyAgent, with or without an explicit address", async () => {
+    const off = buildProxyDispatcher({ proxyForApp: false, proxyUrl: null }, {});
+    const onEnv = buildProxyDispatcher({ proxyForApp: true, proxyUrl: null }, {});
+    const onExplicit = buildProxyDispatcher(
+      { proxyForApp: true, proxyUrl: "http://explicit.example:3128" },
+      {},
+    );
     try {
-      expect(on).toBeInstanceOf(EnvHttpProxyAgent);
       expect(off).toBeInstanceOf(Agent);
       expect(off).not.toBeInstanceOf(EnvHttpProxyAgent);
+      expect(onEnv).toBeInstanceOf(EnvHttpProxyAgent);
+      expect(onExplicit).toBeInstanceOf(EnvHttpProxyAgent);
     } finally {
-      await on.close();
       await off.close();
+      await onEnv.close();
+      await onExplicit.close();
+    }
+  });
+
+  it("explicit address: traffic tunnels through that proxy, loopback bypasses it", async () => {
+    // The fake proxy answers CONNECT and then plays the tunneled origin itself, so a
+    // request to an unresolvable name can only succeed by traveling through the proxy.
+    const connects: string[] = [];
+    const proxy = http.createServer((_req, res) => res.end());
+    proxy.on("connect", (req, socket) => {
+      connects.push(req.url ?? "");
+      socket.write("HTTP/1.1 200 Connection Established\r\n\r\n");
+      let buffered = "";
+      socket.on("data", (chunk: Buffer) => {
+        buffered += chunk.toString("utf8");
+        if (!buffered.includes("\r\n\r\n")) return; // wait for the full tunneled request head
+        socket.end(
+          "HTTP/1.1 200 OK\r\ncontent-type: text/plain\r\ncontent-length: 9\r\nconnection: close\r\n\r\nvia-proxy",
+        );
+      });
+    });
+    const direct = http.createServer((_req, res) => res.end("direct"));
+    const listen = (server: http.Server) =>
+      new Promise<number>((resolve) => {
+        // No hostname: dual-stack, so the localhost fetch below works whether the
+        // resolver picks ::1 or 127.0.0.1 first.
+        server.listen(0, () => resolve((server.address() as AddressInfo).port));
+      });
+    const proxyPort = await listen(proxy);
+    const directPort = await listen(direct);
+    // Empty env: no proxy variables — reaching the fake proxy proves the explicit URL
+    // is honored on its own, and the loopback exemption proves the merge alone (not an
+    // ambient NO_PROXY) produced it.
+    const dispatcher = buildProxyDispatcher(
+      { proxyForApp: true, proxyUrl: `http://127.0.0.1:${proxyPort}` },
+      {},
+    );
+    try {
+      const viaProxy = await undiciFetch("http://proxied.invalid/x", { dispatcher });
+      expect(await viaProxy.text()).toBe("via-proxy");
+      expect(connects).toEqual(["proxied.invalid:80"]);
+      const directRes = await undiciFetch(`http://localhost:${directPort}/`, { dispatcher });
+      expect(await directRes.text()).toBe("direct");
+      expect(connects).toHaveLength(1); // the loopback request never touched the proxy
+    } finally {
+      await dispatcher.close();
+      proxy.close();
+      direct.close();
     }
   });
 });
diff --git a/packages/web/src/components/account/proxy-settings-dialog.tsx b/packages/web/src/components/account/proxy-settings-dialog.tsx
new file mode 100644
index 0000000..a4ae619
--- /dev/null
+++ b/packages/web/src/components/account/proxy-settings-dialog.tsx
@@ -0,0 +1,131 @@
+/**
+ * Admin proxy options dialog (server-global), opened from
+ * the sidebar user menu. A form, not a live surface: two switches — "Application uses
+ * the proxy" (the server's own outbound dispatcher) and "Agent environment uses the
+ * proxy" (command subprocess environments) — share one proxy address, and nothing is
+ * written until Save, which applies everything atomically via a single PUT. The server
+ * validates and normalizes the address (bare "host:port" is stored as
+ * "http://host:port"); a rejected address renders inline under the input (models-dialog
+ * convention) and the atomic PUT writes nothing. Save with no modifications sends no
+ * request and toasts "no changes" (the app's form convention); success
+ * toasts and closes. Settings hydrate fresh on every open; the controls and Save stay
+ * disabled until they arrive, and Cancel/Esc discards edits.
+ */
+import { useEffect, useState } from "react";
+import type { ServerSettings } from "@prismshadow/penguin-server/api";
+import * as api from "../../api/endpoints";
+import { ApiError } from "../../api/client";
+import { S } from "../../lib/strings";
+import { apiErrorText } from "../../lib/api-error";
+import { Button } from "../ui/button";
+import { Input } from "../ui/input";
+import { Modal } from "../ui/modal";
+import { Switch } from "../ui/switch";
+import { toastError, toastInfo, toastSuccess } from "../ui/toast";
+
+export function ProxySettingsDialog({ open, onClose }: { open: boolean; onClose: () => void }) {
+  /** Stored settings as hydrated on open (null until then) — the no-change baseline. */
+  const [settings, setSettings] = useState<ServerSettings | null>(null);
+  // Form drafts; the pre-hydration values mirror the server defaults (on, on, empty).
+  const [proxyForApp, setProxyForApp] = useState(true);
+  const [proxyForAgent, setProxyForAgent] = useState(true);
+  const [proxyUrl, setProxyUrl] = useState("");
+  /** Inline error under the address input (the server's invalid_proxy_url rejection). */
+  const [addressError, setAddressError] = useState<string | null>(null);
+  const [busy, setBusy] = useState(false);
+
+  useEffect(() => {
+    if (!open) return;
+    let cancelled = false;
+    setSettings(null);
+    setAddressError(null);
+    setBusy(false);
+    void api
+      .adminGetSettings()
+      .then((res) => {
+        if (cancelled) return;
+        setSettings(res.settings);
+        setProxyForApp(res.settings.proxyForApp);
+        setProxyForAgent(res.settings.proxyForAgent);
+        setProxyUrl(res.settings.proxyUrl ?? "");
+      })
+      .catch((e: unknown) => {
+        // Controls stay disabled; closing and reopening retries the fetch.
+        if (!cancelled) toastError(apiErrorText(e));
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, [open]);
+
+  const save = async () => {
+    if (settings === null || busy) return;
+    const unchanged =
+      proxyForApp === settings.proxyForApp &&
+      proxyForAgent === settings.proxyForAgent &&
+      proxyUrl.trim() === (settings.proxyUrl ?? "");
+    if (unchanged) {
+      toastInfo(S.common.noChangesToSave);
+      return;
+    }
+    setBusy(true);
+    setAddressError(null);
+    try {
+      await api.adminPutSettings({ proxyForApp, proxyForAgent, proxyUrl });
+      toastSuccess(S.common.saved);
+      onClose();
+    } catch (e) {
+      // The address is the only validated field: its rejection renders inline;
+      // anything else (auth, network) is a generic failure toast.
+      if (e instanceof ApiError && e.code === "invalid_proxy_url") {
+        setAddressError(apiErrorText(e));
+      } else {
+        toastError(apiErrorText(e));
+      }
+    } finally {
+      setBusy(false);
+    }
+  };
+
+  const hydrated = settings !== null;
+  return (
+    <Modal
+      open={open}
+      title={S.settings.proxyDialogTitle}
+      onClose={onClose}
+      footer={
+        <>
+          <Button onClick={onClose} disabled={busy}>
+            {S.common.cancel}
+          </Button>
+          <Button variant="primary" disabled={!hydrated || busy} onClick={() => void save()}>
+            {S.common.save}
+          </Button>
+        </>
+      }
+    >
+      <div className="space-y-4">
+        <div className="flex items-center justify-between gap-3">
+          <span className="text-sm font-medium">{S.settings.proxyForApp}</span>
+          <Switch checked={proxyForApp} onChange={setProxyForApp} disabled={!hydrated} />
+        </div>
+        <div className="flex items-center justify-between gap-3">
+          <span className="text-sm font-medium">{S.settings.proxyForAgent}</span>
+          <Switch checked={proxyForAgent} onChange={setProxyForAgent} disabled={!hydrated} />
+        </div>
+        <Input
+          label={S.settings.proxyAddress}
+          size="sm"
+          value={proxyUrl}
+          placeholder={S.settings.proxyAddressPlaceholder}
+          disabled={!hydrated}
+          {...(addressError !== null ? { error: addressError } : {})}
+          onChange={(e) => {
+            setProxyUrl(e.target.value);
+            if (addressError !== null) setAddressError(null);
+          }}
+        />
+      </div>
+    </Modal>
+  );
+}
diff --git a/packages/web/src/components/layout/sidebar.tsx b/packages/web/src/components/layout/sidebar.tsx
index e714f7f..f54755c 100644
--- a/packages/web/src/components/layout/sidebar.tsx
+++ b/packages/web/src/components/layout/sidebar.tsx
@@ -75,6 +75,7 @@ import { DRAFT_SESSION_ID } from "../../features/chat/chat-page";
 import { clearDraft, sessionDraftKey } from "../../features/chat/draft-cache";
 import { CreateProjectDialog, ProjectSettingsDialog } from "./project-dialogs";
 import { ChangePasswordDialog } from "../account/change-password-dialog";
+import { ProxySettingsDialog } from "../account/proxy-settings-dialog";
 import { UpdateDialog } from "../account/update-dialog";
 import { forceUpdateCheck, updateCheckOutcome, useVersionInfo } from "../../lib/use-version-info";
 
@@ -235,34 +236,11 @@ export function Sidebar({
     }
   };
   /**
-   * Admin-only "use system HTTP proxy" switch (server-global, design § "出网与系统代理"):
-   * null = not hydrated yet. Fetched lazily the first time an ADMIN opens the dropdown —
-   * same laziness as the version info above, and non-admins never call the endpoint (the
-   * row is not rendered for them either). A failed hydration stays null (row disabled)
-   * and is retried on the next open.
+   * Admin-only server-global proxy settings dialog: the menu carries only the opener
+   * row; the controls, their form semantics, and the open-time hydration all live in
+   * ProxySettingsDialog.
    */
-  const [useSystemProxy, setUseSystemProxyState] = useState<boolean | null>(null);
-  useEffect(() => {
-    if (!userOpen || user?.isAdmin !== true || useSystemProxy !== null) return;
-    let cancelled = false;
-    void api
-      .adminGetSettings()
-      .then((res) => {
-        if (!cancelled) setUseSystemProxyState(res.settings.useSystemProxy);
-      })
-      .catch(() => undefined);
-    return () => {
-      cancelled = true;
-    };
-  }, [userOpen, user?.isAdmin, useSystemProxy]);
-  /** Saved immediately on toggle (the user-menu quick-control convention): optimistic flip, reverted with a toast on failure. */
-  const setUseSystemProxy = (value: boolean) => {
-    setUseSystemProxyState(value);
-    void api.adminPutSettings({ useSystemProxy: value }).catch((e: unknown) => {
-      setUseSystemProxyState(!value);
-      toastError(apiErrorText(e));
-    });
-  };
+  const [proxySettingsOpen, setProxySettingsOpen] = useState(false);
   const currentProjectId = currentProject?.projectId ?? null;
   const collapseStoreKey = currentProjectId === null ? null : collapsedGroupsKey(currentProjectId);
   const pinStoreKey = currentProjectId === null ? null : pinnedGroupsKey(currentProjectId);
@@ -1034,19 +1012,6 @@ export function Sidebar({
             <SettingRow label={S.settings.showCliSessions}>
               <Switch checked={showCliSessions} onChange={setShowCliSessions} />
             </SettingRow>
-            {/* Admin-only, server-global (all users), saved immediately on toggle; the
-                tooltip spells out the scope and the loopback exemption. Disabled (showing
-                the default: on) until the stored value has hydrated, so a click can never
-                write a value the admin was not looking at. */}
-            {user?.isAdmin && (
-              <SettingRow label={S.settings.useSystemProxy} title={S.settings.useSystemProxyHint}>
-                <Switch
-                  checked={useSystemProxy ?? true}
-                  onChange={setUseSystemProxy}
-                  disabled={useSystemProxy === null}
-                />
-              </SettingRow>
-            )}
           </div>
           <div className="mt-1 border-t border-gray-100 pt-1 dark:border-gray-800">
             <button
@@ -1059,6 +1024,21 @@ export function Sidebar({
             >
               {S.account.changePassword}
             </button>
+            {/* Admin-only, server-global proxy settings: one menu row opening the
+                dialog (same idiom as Change password above) — the switch, address
+                input and their live-save semantics live in ProxySettingsDialog. */}
+            {user?.isAdmin && (
+              <button
+                type="button"
+                className={menuItemClass}
+                onClick={() => {
+                  setUserOpen(false);
+                  setProxySettingsOpen(true);
+                }}
+              >
+                {S.settings.proxyMenu}
+              </button>
+            )}
             {/* THE update row — one button, two jobs, directly below Change password (owner
                 layout: the menu used to stack a release-notes link, an admin "Update now" row
                 and this check row on top of each other). It reads "Check for updates" and runs
@@ -1156,6 +1136,7 @@ export function Sidebar({
         open={changePasswordOpen}
         onClose={() => setChangePasswordOpen(false)}
       />
+      <ProxySettingsDialog open={proxySettingsOpen} onClose={() => setProxySettingsOpen(false)} />
       <UpdateDialog
         open={updateDialogOpen}
         onClose={() => setUpdateDialogOpen(false)}
@@ -1376,18 +1357,9 @@ function SessionRow({
   );
 }
 
-function SettingRow({
-  label,
-  title,
-  children,
-}: {
-  label: string;
-  /** Optional row tooltip (e.g. the system-proxy row's scope + loopback-exemption hint). */
-  title?: string;
-  children: ReactNode;
-}) {
+function SettingRow({ label, children }: { label: string; children: ReactNode }) {
   return (
-    <div {...(title !== undefined ? { title } : {})}>
+    <div>
       <p className="mb-1 text-[11px] font-medium text-gray-500 dark:text-gray-400">{label}</p>
       {children}
     </div>
diff --git a/packages/web/src/lib/strings-en.ts b/packages/web/src/lib/strings-en.ts
index df2d9a1..20b871b 100644
--- a/packages/web/src/lib/strings-en.ts
+++ b/packages/web/src/lib/strings-en.ts
@@ -33,11 +33,15 @@ export const en: Strings = {
     language: "Language",
     /** Sidebar Session list: also show CLI-created Sessions (default off — the list then never scans the Trace directories). */
     showCliSessions: "Show CLI sessions",
-    /** Admin-only server-global switch (design § "出网与系统代理"): saved immediately on toggle. */
-    useSystemProxy: "Use system HTTP proxy",
-    /** Row tooltip: scope (server + its child processes, server-wide) and the loopback exemption. */
-    useSystemProxyHint:
-      "Whether the server and its child processes (update checks, LLM requests, agent commands) reach the internet through the proxy named by HTTP_PROXY / HTTPS_PROXY. Applies server-wide; loopback addresses (localhost, 127.0.0.1, ::1) always connect directly. When off, the server connects directly and the proxy variables are removed from agent command subprocess environments.",
+    /** Admin-only user-menu row opening the proxy options dialog. */
+    proxyMenu: "Proxy options…",
+    proxyDialogTitle: "Proxy options",
+    /** The dialog's two switches: the server's own outbound traffic / agent command subprocess environments. */
+    proxyForApp: "Application uses the proxy",
+    proxyForAgent: "Agent environment uses the proxy",
+    /** The shared explicit proxy address (empty = follow the proxy environment variables). */
+    proxyAddress: "Proxy address",
+    proxyAddressPlaceholder: "Empty = follow system proxy",
     theme: "Theme",
     themeLight: "Light",
     themeDark: "Dark",
@@ -1175,6 +1179,8 @@ Scenarios:
       task_in_progress: "This Session already has a task running.",
       version_conflict: "The snapshot's version is not newer than the current one.",
       invalid_title: "The title is invalid.",
+      invalid_proxy_url:
+        "Invalid proxy address — use http://host[:port], https://host[:port], or host[:port].",
       invalid_trace: "This file is not a valid Trace file.",
       trace_session_exists:
         "This agent already has a Session with that id; a duplicate Trace cannot be imported.",
diff --git a/packages/web/src/lib/strings.ts b/packages/web/src/lib/strings.ts
index 4e50adf..3007bc0 100644
--- a/packages/web/src/lib/strings.ts
+++ b/packages/web/src/lib/strings.ts
@@ -35,11 +35,15 @@ export const zh = {
     language: "语言",
     /** Sidebar Session list: also show CLI-created Sessions (default off — the list then never scans the Trace directories). */
     showCliSessions: "显示 CLI 会话",
-    /** Admin-only server-global switch (design § "出网与系统代理"): saved immediately on toggle. */
-    useSystemProxy: "使用系统 HTTP 代理",
-    /** Row tooltip: scope (server + its child processes, server-wide) and the loopback exemption. */
-    useSystemProxyHint:
-      "服务端及其子进程（更新检查、LLM 请求、Agent 命令）出网时是否使用 HTTP_PROXY / HTTPS_PROXY 环境变量指定的代理，对整个服务端全局生效；回环地址（localhost、127.0.0.1、::1）始终直连。关闭后服务端一律直连，并从 Agent 命令子进程环境中移除代理变量。",
+    /** Admin-only user-menu row opening the proxy options dialog. */
+    proxyMenu: "代理选项",
+    proxyDialogTitle: "代理选项",
+    /** The dialog's two switches: the server's own outbound traffic / agent command subprocess environments. */
+    proxyForApp: "应用程序使用代理",
+    proxyForAgent: "Agent 环境使用代理",
+    /** The shared explicit proxy address (empty = follow the proxy environment variables). */
+    proxyAddress: "代理地址",
+    proxyAddressPlaceholder: "留空 = 跟随系统代理",
     theme: "主题",
     themeLight: "浅色",
     themeDark: "深色",
@@ -63,18 +67,20 @@ export const zh = {
 
   /** Version footer, update reminder, and admin self-update in the sidebar user menu. */
   update: {
-    /** Version-line date label (owner-specified wording); `date` is formatMonthDay output, e.g. 「最近更新日期 7 月 26 日」. */
+    /** Version-line date label (owner-specified wording); `date` is formatMonthDay output. */
     lastUpdated: (date: string) => `最近更新日期 ${date}`,
     /** Superscript badge on the version lines when the update check found a newer release (owner-specified wording). */
     newVersionBadge: "有新版本可用",
     newVersion: (v: string) => `新版本 v${v} 可用`,
     /**
-     * 用户菜单里**唯一**的更新行：未知新版本时显示「检查更新」并执行手动检查；已知新版本后改为
-     * newVersion() 文案，点击打开更新弹窗（弹窗内含更新说明链接，管理员另有自更新操作）。
+     * The sidebar user menu's SINGLE update row: it reads checkNow until a newer release
+     * is known and runs the manual check; once one is known it reads newVersion() and
+     * opens the update dialog instead (which carries the release-notes link and, for
+     * admins, the self-update action).
      */
     checkNow: "检查更新",
     checking: "检查中…",
-    /** 手动检查发现新版本时的成功提示；下方同一行即变为更新入口。 */
+    /** Success toast when the manual check finds a newer release; the row below turns into the update entry. */
     foundNew: (v: string) => `发现新版本 v${v}，点击下方更新入口即可安装`,
     upToDate: "已是最新版本",
     checkFailed: "检查更新失败，请稍后重试",
@@ -88,7 +94,7 @@ export const zh = {
     unsupported: "当前安装方式不支持在线更新",
     confirmBody:
       "将下载最新版本并安装到服务器上的安装目录（数据目录不受影响）。安装完成后需要重启服务才会生效。",
-    /** 非管理员看到的说明（可查看更新说明，但不能在此执行更新），替代 confirmBody。 */
+    /** Copy shown to non-admins in place of confirmBody (they can read the release notes but cannot run the update here). */
     adminOnly: "只有管理员可以在这里执行更新。",
   },
 
@@ -178,14 +184,14 @@ export const zh = {
     idHint: "2~64 位：小写字母开头，仅小写字母、数字与下划线；创建后不可修改",
     idPrefixHint: "id 固定以「用户名-」为前缀，后接小写字母、数字或下划线；创建后不可修改",
     name: "显示名（可选，缺省为 Project id）",
-    /** Project 设置里的显示名字段（此处必填，与新建对话框的「可选」措辞区分）。 */
+    /** Display-name field in Project settings (required here, unlike the create dialog's "optional" wording). */
     displayName: "显示名",
     settings: "Project 设置",
     settingsTitle: "Project 设置",
     members: "成员",
     addMember: "添加成员",
     removeMember: "移除",
-    /** 新对话默认值分节（Project 设置）：预填每个新建对话的 Agent / 工作目录 / 审批模式 / 思考等级 / 默认模型。 */
+    /** New-conversation defaults section (Project settings): prefills each new conversation's agent / working directory / approval mode / thinking level / default model. */
     chatDefaultsTitle: "新对话默认值",
     chatDefaultsHint: "新建对话时预填的默认值：Agent、工作目录、审批模式、思考等级与默认模型。",
     chatDefaultsAgent: "Agent",
@@ -193,7 +199,7 @@ export const zh = {
     chatDefaultsApprovalNotSet: "未设置（默认全部放行）",
     chatDefaultsThinkingNotSet: "未设置（跟随智能体配置）",
     chatDefaultsWorkspaceHint: "留空表示使用临时工作区",
-    /** 模型默认值与模型页同源（同一个 default_model），此处仅是另一处入口。 */
+    /** The model default shares its source with the Models page (the same default_model); this is just another entry point. */
     chatDefaultsModelHint: "与模型页的默认模型同步",
     deleteProject: "删除 Project",
     deleteConfirm: "确认删除该 Project？项目目录将被递归删除，不可恢复。",
@@ -367,7 +373,7 @@ export const zh = {
     displayNameHint: "留空则展示模型 ID",
     providerGroup: "分组",
     contextWindow: "上下文窗口",
-    /** 单位后缀，显示在上下文窗口/最大输出长度输入框内右侧。 */
+    /** Unit suffix shown inside the right edge of the context-window / max-output-length inputs. */
     tokenUnit: "Token",
     contextWindowHint: "留空表示未知",
     maxTokens: "最大输出长度",
@@ -600,13 +606,13 @@ export const zh = {
     workspaceAuto: "临时工作区",
     workspaceClear: "改用临时工作区",
     workspaceDirInvalid: "目录不存在或无法访问，已回退",
-    /** 侧栏对话列表的分组切换（默认按工作区）与工作区分组。 */
+    /** Grouping toggle of the sidebar conversation list (workspace grouping is the default) and the workspace groups. */
     groupByWorkspace: "按工作区分组",
     groupByAgent: "按 Agent 分组",
     tempWorkspaces: "临时工作区",
     newSessionInWorkspace: "在此工作区新建对话",
     draftSubtitle: "最擅长 AI 开发任务的自进化 Agent",
-    /** 首页示例的折叠分组名（书签式，同时只展开一个）。 */
+    /** Collapsed group names for the home-page examples (bookmark style; only one open at a time). */
     exampleFolders: {
       webapps: "搭建网页应用",
       agents: "搭建和优化智能体",
@@ -1149,6 +1155,8 @@ Benchmark：
       task_in_progress: "该 Session 已有任务在运行。",
       version_conflict: "快照版本不高于当前版本。",
       invalid_title: "标题无效。",
+      invalid_proxy_url:
+        "代理地址无效：应为 http://主机[:端口]、https://主机[:端口] 或 主机[:端口]。",
       invalid_trace: "该文件不是有效的 Trace 文件。",
       trace_session_exists: "该 Agent 已存在同名 Session，无法导入重复的 Trace。",
     },