penguin-harness/packages/docs/content/server-api.en.md

title, description

title	description
Server API	HTTP API reference — authentication, routes, the SSE streaming protocol, and DTO type imports.

The PenguinHarness server exposes a same-origin HTTP API used by the bundled Web App and by any other HTTP client. This page is the reference: authentication, route tables, and the SSE streaming protocol. For starting the server, see the Quickstart.

Overview

• Stack: Hono + @hono/node-server, requires Node >= 24;
• Storage: SQLite (built-in node:sqlite, WAL mode) holds only indexes and aggregates — users, auth sessions, Project authorization, Agent / Session indexes, usage, UI preferences, error records, and Schedule state; all Agent, Trace, and Workspace data stays as files under ~/.penguin/data, shared with the CLI / SDK — see the Configuration Reference;
• Binding: defaults to 127.0.0.1:7364, adjustable via the PORT / HOST environment variables;
• Request bodies: writes accept JSON only (Content-Type check, one of the CSRF defenses), capped at 20MB;
• Errors share a single shape:

{ "error": { "code": "<machine-readable code>", "message": "<user-facing text>" } }

Source layout

packages/server/src
├── index.ts / config.ts / app.ts   # startup entry · env config · Hono assembly (createApp binds no port — testable)
├── api/types.ts                    # the outward DTO contract (type-only import via the "./api" subpath)
├── auth/                           # scrypt passwords, admin seeding, cookie sessions, auth middleware
├── db/                             # node:sqlite connection, schema SQL, one repo per table
├── http/                           # error bodies, request validation, SSE adapter, routes/ all route groups
├── runtime/                        # session-manager (runtime driving) · channel (SSE ring buffer)
│                                   # approvals · usage-recorder · scheduler · title-generator
└── services/                       # authorization rules, TOML/YAML config IO, Session/Trace/usage/snapshot services

Authentication

• Cookie session: penguin_session (HttpOnly, SameSite=Lax), valid for 7 days with sliding renewal;
• Passwords are stored as scrypt hashes; the server keeps only the sha256 of the session token, never the plaintext;
• No open registration: the built-in admin admin / penguin-2026 is seeded at startup, and all other accounts are created by an admin;
• Same-origin only — no CORS middleware is enabled.

curl -c cookies.txt -H "Content-Type: application/json" \
  -d '{"userId":"admin","password":"penguin-2026"}' \
  http://127.0.0.1:7364/api/auth/login

Route Reference

Auth and Account

Method	Path	Description
POST	/api/auth/login	Log in: {userId, password} → {user}
POST	/api/auth/logout	Log out, returns 204
GET	/api/me	Current user info
PUT	/api/me/password	Change password: {oldPassword, newPassword}
GET	/api/me/prefs	Read UI preferences
PUT	/api/me/prefs	Write UI preferences (shallow merge)

User Administration (admin only)

Method	Path	Description
GET	/api/admin/users	List users
POST	/api/admin/users	Create a user: {userId, password}
POST	/api/admin/users/:userId/password	Reset a password (invalidates all of that user's login sessions)
DELETE	/api/admin/users/:userId	Delete a user

Version and Self-Update

Method	Path	Description
GET	/api/version	Running release identity: {version, buildDate} (buildDate is the running version's release date, stamped at build time — no network; null in a dev/source build or a release that predates the stamping)
GET	/api/version/update-check	Compares the newest GitHub release with the running version: {currentVersion, latestVersion, updateAvailable, releaseUrl, publishedAt, checkedAt, disabled?, error?}; ?force=1 (the manual "check for updates" action) bypasses the TTL cache, and the outcome is cached as usual
POST	/api/version/update	Admin only. Runs the CLI self-update (penguin update --yes) on the server host: {status, output, needsRestart}

update-check is the server's only outbound internet call and is strictly fail-soft: a failed lookup still returns 200 with error set (network / rate_limited / bad_response) and latestVersion: null, results are cached in memory (success 1 h, failure 10 min), and setting PENGUIN_UPDATE_CHECK=off disables the lookup entirely (disabled: true, no network call). The update status is updated (restart the service to run the new version), failed, or unsupported — the latter both when the server was not started via penguin server|web (reason: "not_launched_via_cli") and when the CLI refuses (source checkout, unrecognized install layout, Windows); output carries the tail of the CLI's own output.

Projects and Members

Method	Path	Description
GET	/api/projects	Projects visible to the current user
POST	/api/projects	Create a Project
DELETE	/api/projects/:projectId	Delete a Project
GET	/api/projects/:projectId/members	List members
POST	/api/projects/:projectId/members	Add a member: {userId}
DELETE	/api/projects/:projectId/members/:userId	Remove a member

Member writes are owner-only.

Models

Method	Path	Description
GET	/api/projects/:projectId/models	List models (api_key masked)
PUT	/api/projects/:projectId/models	Full-table replace, keyed by (provider, modelId)
POST	/api/projects/:projectId/models/test	Connectivity test: {provider, modelId, …} → {ok, latencyMs?, message?}

Every endpoint that names a model takes the complete (provider, modelId) pair. Nothing is inferred: a request carrying only one half is a 400, never a lookup. Where the reference itself is optional (Session creation, Schedules), omitting both halves selects the Project's default model.

PUT /models also invalidates the Project's cached Session runtimes (same effective-value semantics as a vault update): no hot swap into a run already in flight, but the next Task on any Session of the Project re-resumes and reads the new api_key / base_url. It additionally publishes a credentials_updated event to the Project's open Session channels (see Streaming below), and the models response carries updatedAt (the config file's mtime) — the Web App compares it against the last auth failure to decide whether an auth-dead composer should stay disabled.

Agents

The paths below omit the /api/projects/:projectId prefix.

Method	Path	Description
GET / POST	/agents	List / create Agents
DELETE	/agents/:agentId	Delete an Agent
GET / PUT	/agents/:agentId/config	Read / write config (AGENTS.md + system_config.yaml; PUT preserves YAML comments)
GET / PUT	/agents/:agentId/vault	Vault environment variables (values masked; PUT is a full replace)
GET	/agents/:agentId/export	Export the Agent State snapshot (tar.gz download)
POST	/agents/:agentId/import	Import a snapshot: {dataBase64, confirm?}; 409 on version conflict without confirm
GET / POST	/agents/:agentId/skills	List / install installed Skills
DELETE	/agents/:agentId/skills/:name	Uninstall a Skill
GET	/agents/:agentId/benchmarks	Benchmark scoring data (read-only)

Schedules

Method	Path	Description
GET / POST	/agents/:agentId/schedules	List scheduled tasks / create one (409 if the name exists)
GET / PUT / DELETE	/agents/:agentId/schedules/:name	Read / update / delete a single task

Schedule writes are owner-only. A task in new-Session mode carries modelId and provider together or not at all; the pair is checked against the Project's model table when the task is saved and again when the scheduler reconciles it.

Session Creation and Directory Browsing

Method	Path	Description
GET	/agents/:agentId/sessions	List Sessions (including run state)
POST	/agents/:agentId/sessions	Create a Session: {modelId?, provider?, workspace?, approvalMode?} → 201
GET	/dirs?path=	Server-side directory browser (backs the Workspace picker)

On Session creation, modelId and provider are both-or-neither: send the complete pair to pick a model, or omit both to take the Project's default model — one without the other is a 400. The Workspace defaults to an auto-created temporary directory, and the approval mode defaults to allow-all.

Usage and Traces (Agent Level)

Method	Path	Description
GET	/usage	Usage statistics; query parameters from, to, groupBy, agentId, provider, modelId
GET	/agents/:agentId/traces	Date → Session drill-down structure of Trace files
GET	/agents/:agentId/traces/:sessionId/:index	Read Trace events (offset / limit pagination)
GET	/agents/:agentId/traces/:sessionId/:index/analysis	Trace performance analysis
GET	/agents/:agentId/traces/:sessionId/:index/download	Download the raw Trace file (JSONL attachment)
POST	/agents/:agentId/traces/import	Import a Trace file: {dataBase64} → {sessionId, index, date}

Trace download is available to any member; import is owner-only (like the Agent snapshot import, capped at 14MB). An imported file must be valid Trace JSONL whose first record is a session_meta with a filename-safe session_id; a session id the Agent already has is rejected (409 trace_session_exists), so an imported file always becomes index 001 of a new Session, landing in the local date directory of its first record's timestamp.

Session-Level Endpoints

The paths below omit the /api/sessions/:sessionId prefix. For the storage model behind Sessions and Traces, see Sessions and Traces.

Method	Path	Description
GET	/	Session info (the single-session GET additionally carries tracePath, the absolute path of the latest Trace file; list rows omit it)
PATCH	/	Update: {approvalMode?, archived?, title?}
DELETE	/	Delete the Session (along with its Traces and scratch files)
GET	/messages	Full OmniMessage history; while a Task runs the response also carries live (the in-progress stream tail, see below)
GET	/stream	SSE event stream (next section)
POST	/tasks	Start a Task: {input: TaskInputPart[], thinkingLevel?, queueIfBusy?} → 202. With queueIfBusy, a busy session holds the input as a follow-up (queued: true) and auto-starts it as an ordinary next task once idle; task_state events report the queued count
POST	/steer	Mid-run steering: {text} queues a message for the running Task (delivered between turns as a standalone [user_steering] user message) → 202; 409 not_running when no Task is in progress
POST	/approvals/:toolCallId	Approval decision: {decision} is allow or deny → 204
POST	/abort	Interrupt the current Task: 202 when triggered, 204 when idle
POST	/retry-now	"Retry now" on the reconnect countdown: skips the in-progress backoff wait, firing the next retry immediately (attempt counter unchanged) → 200 {skipped} — skipped:false is the benign "no wait in progress" case, never an error
POST	/compact	Trigger context compaction: 202; 409 nothing_to_compact when there is nothing to compact
GET	/files?path=	Browse the Workspace directory
GET	/files/content?path=&download=&preview=	Read a Workspace file (download=1 serves it as an attachment, preview=1 renders it in a sandbox — see below)
GET	/files/preview-redirect?path=	"Open in a new tab" for html: mints a signed token and 302s to the separate preview origin
POST	/files/stat	Batch existence check: {paths}
PUT	/files/content?path=	Upload a file: {dataBase64}, capped at 14MB
GET	/traces	List this Session's Trace files
GET	/traces/:index	Read Trace events (paginated)
GET	/traces/:index/analysis	Trace performance analysis
GET	/scratchpad/:fileName	Read a session scratch file (e.g. input images)

General conventions: Sessions the user cannot access always return 404 — their existence is never leaked; only one Task or compaction runs per Session at a time, and conflicts return 409 (task_in_progress / compacting).

The live field on GET /messages

The Trace stores only complete messages (streaming partial_* never reaches disk), so history alone cannot show a message that is still streaming. While the Session is running or compacting, the messages response therefore also carries the in-progress stream tail:

interface MessagesResponse {
  messages: OmniMessage[];
  live?: {
    // The Session channel's most recently assigned SSE event id (`<epoch>-<seq>`):
    // every event published up to and including this id is already reflected in `fragments`.
    cursor: string;
    // One synthetic `partial_* start` OmniMessage per open streaming fragment, whose
    // payload carries the full accumulated content so far (text/thinking prefix,
    // tool-call name + accumulated arguments, tool-output prefix + images), with the
    // original `origin` chain preserved (subagent fragments included).
    fragments: OmniMessage[];
  };
}

cursor and fragments are captured atomically before the trace read starts. A client using the connect-first pattern (below) applies them after history: when the cursor's epoch matches the epoch of the SSE events it has buffered, it drops every buffered partial event with seq ≤ cursor (their content is already accumulated inside fragments), feeds fragments through its normal reducer, then replays the rest of the buffer. Buffered complete messages are never dropped by the cursor — the regular overlap dedup decides for them. live is omitted while idle.

Workspace files may be Agent-generated, so GET /files/content treats them as untrusted: every response carries X-Content-Type-Options: nosniff, and the rest of the headers depend on the two flags (download=1 wins over preview=1):

Query	Content-Type	Content-Disposition	Content-Security-Policy
neither	text/plain; charset=utf-8 for .html / .htm / .svg, the real type otherwise	inline	—
preview=1	the real type (text/html, image/svg+xml, …)	inline	sandbox allow-scripts allow-popups allow-modals allow-forms, sent only for .html / .htm / .svg
download=1	the real type	attachment	—

The filename always rides along as filename*=UTF-8'' with percent-encoding. preview=1 is where the preview redirect falls back when no separate preview origin is available: the document keeps its real type and does render and run, but the sandbox deliberately omits allow-same-origin, so it lands in an opaque origin and can reach neither this origin's cookies nor the API. That isolation is also why localStorage, document.cookie and third-party embeds do not work there.

Preview on a separate origin

Both the Files panel's rendered HTML view (an iframe) and "open in a new tab" go through GET /files/preview-redirect?path=, which authenticates the caller, then mints a short-lived HMAC token and 302s to a different origin:

GET  /api/sessions/:sessionId/files/preview-redirect?path=index.html
302  Location: http://localhost:7364/preview/<token>/index.html
GET  /preview/<token>/<relative path>          (unauthenticated; the token is the credential)

• Why a separate origin. The page needs a real origin to have working storage, cookies and third-party embeds — but it must not be the app's origin, or Agent-written HTML would run with the session cookie. Locally the app is canonicalized onto localhost and previews are served from 127.0.0.1; cookies are keyed by host and ignore port, so those are separate cookie jars while a second port would not be. Otherwise PENGUIN_PREVIEW_ORIGIN applies; with neither (a wildcard or non-loopback bind, or the variable unset), the redirect falls back to the same-origin sandbox above and previewIsolated on GET /api/me reports false so the UI can say so first.
• In-app rendering rides the same URL. The Files panel embeds the redirect URL in an iframe sandboxed with allow-scripts allow-same-origin allow-forms allow-popups allow-modals allow-downloads — allow-same-origin grants the preview origin's identity, not the App's, so this stays strictly tighter than the sandbox-free new tab. Without a separate preview origin the panel instead falls back to inline srcdoc rendering (allow-scripts only, plus an in-memory storage shim), where relative subresources cannot load. Note that some browsers partition or block storage inside a cross-site iframe, so a page may behave slightly differently in the panel than in the top-level tab.
• The preview host serves only /preview/*. It is the same process as the app, so it answers /api with 401 and 302s every other route to the canonical app host. A session cookie is therefore never set or honored on the preview host, and Agent HTML there cannot reach the API same-origin. (For a deployed PENGUIN_PREVIEW_ORIGIN, the reverse proxy must enforce the equivalent: route only /preview/* to the app on that origin.)
• Path-based, not a query parameter, so a page's relative subresources (app.js, style.css, images) resolve against the document and load under the same token.
• The token binds the Session, the preview host and an expiry. The host binding is load-bearing: the same process also answers on the app origin, so /preview/... refuses to serve there — otherwise it would be a same-origin XSS. Access is read-only and scoped to that Session's Workspace, and the path is re-resolved server-side, so .. and symlink escapes are rejected as before.
• Responses carry Referrer-Policy: no-referrer, or the token-bearing URL would leak through Referer to every third party the page embeds — a risk that exists precisely because embeds now work.
• Bad token, expired token, wrong host and out-of-bounds path all answer a bare 404: the endpoint is unauthenticated and must not confirm what exists.

Key request bodies (explicit keys):

// POST /api/sessions/:sessionId/tasks — start a Task
interface TaskCreateRequest {
  input: TaskInputPart[];
  // Thinking level for this Task (a per-turn parameter, one of the five names; 400 otherwise);
  // omitted = falls back to the Agent config
  thinkingLevel?: "none" | "low" | "medium" | "high" | "xhigh";
}
type TaskInputPart =
  | { type: "text"; text: string }
  | { type: "image_url"; imageUrl: string };   // pasted images arrive as data URLs

// POST /api/sessions/:sessionId/approvals/:toolCallId
interface ApprovalDecisionRequest {
  decision: "allow" | "deny";
}

The Web's /model switch has no dedicated endpoint: like the @ handoff, it composes the ordinary APIs above — session creation opens a new Session for the same Agent (the chosen model, the source Workspace carried over), then POST /tasks sends a first message opening with a [model_switch_from] source block (the source session id, its tracePath, the Workspace, and the previous model pair); the model reads that Trace file itself when it needs the earlier history.

Streaming (SSE)

Real-time delivery uses Server-Sent Events, not WebSocket, on two channels (the ordering semantics of what the channels carry are on Message Flow & Ordering):

Channel	Path	Contents
Per Session	GET /api/sessions/:sessionId/stream	The Session's message stream and run events
Per user	GET /api/events	hello handshake and cross-Session notifications (schedule_fired / schedule_queued / session_created)

Wire Format

Default (unnamed) SSE events carry raw OmniMessage envelopes as single-line JSON — the same protocol the SDK yields and the Trace stores, see the OmniMessage Protocol. Events named server_event carry the ServerEvent union:

export type ServerEvent =
  | { type: "approval_request"; toolCall: OmniMessage<ToolCallPayload>; origin?: string[] }
  | { type: "task_state"; state: "idle" | "running" | "compacting" }
  | { type: "session_title"; sessionId: string; title: string }
  | { type: "resync_required" }
  | { type: "credentials_updated" }
  | { type: "hello" }
  | { type: "session_created"; projectId: string; agentId: string; sessionId: string; source: SessionSource }
  | { type: "schedule_fired"; projectId: string; agentId: string; name: string; sessionId: string }
  | { type: "schedule_queued"; projectId: string; agentId: string; name: string; sessionId: string };

Event	Fired when
approval_request	A tool call escalated to human approval: every call under always-ask, plus rw / unknown-permission calls under read-only; pending approvals are resent on reconnect
task_state	The Session's run state flips (idle / running / compacting)
session_title	The model-generated title after the first turn has been persisted
resync_required	The Last-Event-ID was evicted from the buffer; the client must refetch history
credentials_updated	The Project's model credentials changed (PUT /models): cached runtimes were invalidated, so the client clears any auth-dead composer state
hello	Handshake on the user channel
session_created	A new Session was registered (e.g. a subagent session)
schedule_fired	A scheduled task fired and was delivered
schedule_queued	The target Session is running; this firing was queued

Delivery Guarantees

• Event ids are monotonic per channel, shaped <epoch>-<seq>;
• Each channel keeps a bounded replay buffer (most recent 10,000 events or 8MB);
• Reconnecting with Last-Event-ID replays the gap on a buffer hit; on a miss the server first sends resync_required, and the client refetches /messages before continuing;
• A heartbeat comment line is written every 20 seconds;
• Event order: on a reconnect carrying Last-Event-ID, the replayed gap (or resync_required) arrives first, then the initial events — the authoritative task_state snapshot and still-pending approval_requests — then the live stream. A fresh connection (no Last-Event-ID) skips replay, so its first event is the task_state snapshot.

Recommended Client Pattern

The order the bundled Web App uses:

1. Connect /stream first and buffer incoming events;
2. GET /messages for the full history;
3. If the response carries live (a Task is running), drop the buffered partials the cursor already covers and seed the live.fragments on top of history — the in-progress message reappears with its streamed prefix intact;
4. Replay the buffer, deduplicating the overlap;
5. Go live.

Type Imports

All DTO types are importable type-only from the server package's @prismshadow/penguin-server/api subpath:

import type { ServerEvent, SessionInfo } from "@prismshadow/penguin-server/api";