Yaowei Zheng
2.7 KiB
Backward compatibility in this batch
Per the repo rule, every compatibility decision of the batch is recorded here once; the feature entries reference this file instead of re-telling it.
Legacy thinking_level in old Traces is ignored on resume (owner-directed)
Old Traces recorded a thinking_level in their session_meta; since 0.1.2 the field is no longer written, and resume used to keep honoring it when present. The owner chose explicit incompatibility over continued support: resume now ignores the field entirely and always reads the Agent's current config. Old shape tolerated: the field may appear in old meta JSON and is skipped without error (the Trace itself stays fully readable). Scope: resumeSession only; live behavior and the per-turn picker were never affected. User action: none — the one visible consequence is that a resumed legacy subagent session follows the resuming Agent's configured level instead of its spawn-time inherited one. Removal: nothing to remove; no compat code was retained beyond the tolerant skip.
Existing Agents without {{SHELL}} get the Shell line via an assembly-time fallback
The Shell: environment line ships in the default system_prompt template through a new {{SHELL}} placeholder — but system_config.yaml is baked at Agent creation and never auto-upgraded, so every Agent created before this release lacks the placeholder, and on Windows its model would never learn which shell exec_command speaks. Rather than a disk migration, prompt assembly applies a narrow fallback: on win32 only, when the template contains no {{SHELL}} and the output carries no Shell: line already, the line is appended to the Environment block in memory. Old shape tolerated: pre-{{SHELL}} templates (and templates that hardcode their own Shell: line, which win). Scope: prompt assembly on Windows; POSIX output is byte-identical, no file is rewritten. User action: none; resetting an Agent's config to defaults also picks up the placeholder and makes the fallback moot for that Agent. Removal: delete the fallback once pre-{{SHELL}} Agent configs are no longer expected in the wild (tracked by the comment at the fallback site).
Additive protocol fields need no handling
The StopReason enum's sixth value auth (old readers fall through like failed; old Traces never contain it), request_end's message and retry_in_ms, the credentials_updated server event, and updatedAt on the models response are all additive: old Traces simply lack them, old readers ignore them, and nothing interprets legacy data differently. Recorded here only to state that the check was made; there is no compat behavior to retire.