The 2026-07-16 explicit-turn-cancellation note still described a frozen,
detached signal reason and a two-variant cause union. The README paragraph
added here points readers at that note as the owner of the signal
lifecycle, so the stale mechanism was load-bearing.
It now records why freezing the caller's cause is not an alternative:
undici assigns `stack` from strict-mode code, so a frozen reason makes
fetch reject with `TypeError: Cannot add property stack` in place of the
abort reason.
Also names `turn/end`'s declared `TurnEndCancelCause` in the README and
takes the reviewer's helper-doc wording.
Node's fetch assigns an enumerable `stack` string onto the abort reason
object it receives, and the loop logged that same object into `turn/end`.
The undici trace became durable session data under a field no reader
declares. A transport adding a property JSON discards instead made
`Session.append` reject the ending, leaving a turn with no close.
`abortedCancelCause()` narrows the untyped `AbortSignal.reason` once and
copies the declared fields, replacing the three `as AgentCancelCause`
assertions at the two read sites and the log write.
Preserve the V3 system-prompt projection while adopting master’s per-agent frozen-message provenance and frontend performance gates. Keep benchmark workload admission and diagnostics fixes intact, and retain both migration and first-open/reopen lifecycle guarantees.
Seed the request surface watermark from the attached session so a replacement before the first resumed request consolidates retained prompt versions. An unchanged resume still continues the series. Actual-loop replacement regression fails before the fix; 53 focused tests and the agent-loop project typecheck pass.
Every same-step attempt resolves its bound route and reconciles the accepted rendered prompt against the current surface before deriving history. Preserve assembly, pre-step admission and entered users exactly once; compaction retries must not resurrect an older surviving prompt.
Normalize a broken request series to the current head plus dormant empty later system nodes, even if later versions survive or the effective text is unchanged. This removes the later-survivor exception without a delete operation and avoids appending instructions after already-admitted users on retry. Capture surface generation after reconciliation so subsequent ordinary retries do not emit phantom series headers.
Tests: both compaction cases fail before the fix (stale head, or stale later survivor), then pass with real loop/MockAdapter, pi-ai conversion and source-event reconstruction. Assert two retries keep one assembly/pre-step/user admission, preserve rendered text across section changes, and log one series boundary. Add unchanged-text explicit/tool series regressions. 391 loop tests with exact agent.ts/runtime-context.ts coverage pass at 100%; final admission spec has 11 passing cases. Source tsc and focused lint pass. Update EN/ZH implementation and owning rationale plus lifecycle retry documentation.
Resolve agent/request and prepareCall inside the accepted open step before committing system and user input. Preserve prompt-assembly model selection, bind capability and dispatch to the same prepared adapter, then log the envelope and derive the request synchronously. Preparation cancellation leaves a balanced empty step with no admitted input.
Normalize incapable-route retained prompt versions with logged per-node empty replacements and a current head, including unchanged rendering and resumed history. Dormant empty tails do not override the effective prompt. No new event or delete operation.
Tests: 389 agent-loop cases pass with exact agent.ts/runtime-context.ts coverage at 100% for all metrics; tsc -b packages/core/agent-loop/tsconfig.json passes. Seven actual-loop MockAdapter cases exercise pi-ai conversion, source-event reconstruction, both route transitions, resume, cancellation barriers, and bound selection. Stale-capability negative control fails all three transition regressions. Update EN/ZH request visibility, lifecycle generator, and owning rationale. Broad catalogs, recorded SDK/GUI and aggregate gates remain parent-owned.
Consolidate the existing in-history capability, loop, UI and artifacts into one baseline. Preserve the reviewed tree so each independently verified correction has a subsequent rationale-rich commit.
Consolidate the representation-change PR and its rebase reconciliations into one baseline. Preserve the exact tree and keep the in-history feature in the dependent PR. Follow-up fixes remain separate.
Render reconstructable system prompts at each request-series boundary, preserve series declarations through pre-step wrappers, and keep the presentation and replay snapshots aligned across clients.
_Kerman