🚧 4JK4MP task: Allow replacement after a rejected external-agent result [202608241454-4JK4MP]

[densmirnov]

Task: 202608241454-4JK4MP
Title: Allow replacement after a rejected external-agent result
Canonical task record: .agentplane/tasks/202608241454-4JK4MP/README.md

Summary

Allow replacement after a rejected external-agent result

Fix the external-agent supervisor so a schema-valid result that is durably recorded but later rejected by pre-apply implementation-authority validation does not permanently lock the exchange or replay the same failure. Preserve immutable accepted/consumed result semantics and effect-in-doubt safety. Add a regression for completed implementation with no workspace change followed by a corrected replacement exchange, plus conflicting replay coverage. This is a v0.7.8 release blocker discovered by task 202608241434-NCQYZ4; it must remain a separate code Task and merge before a fresh release attempt.

Scope

• In scope: Fix the external-agent supervisor so a schema-valid result that is durably recorded but later rejected by pre-apply implementation-authority validation does not permanently lock the exchange or replay the same failure. Preserve immutable accepted/consumed result semantics and effect-in-doubt safety. Add a regression for completed implementation with no workspace change followed by a corrected replacement exchange, plus conflicting replay coverage. This is a v0.7.8 release blocker discovered by task 202608241434-NCQYZ4; it must remain a separate code Task and merge before a fresh release attempt.
• Out of scope: unrelated refactors not required for "Allow replacement after a rejected external-agent result".

Verification

• State: ok
• Note: Verified: CLI-owned declared checks passed; independent EVALUATOR review is pending.
• Canonical workflow state lives in the task README.

Raw evidence

• Updated: 2026-08-24T16:58:00.402Z
• Branch: task/202608241454-4JK4MP/allow-replacement-after-a-rejected-external-agen
• Head: computed live by agentplane pr check / agentplane integrate

 ...n-cli.core.task-advance-effect-recovery.test.ts | 38 ++++++++--
 ...un-cli.core.task-advance.blocked-result.test.ts | 87 ++++++++++++++++++++++
 .../src/commands/task/external-agent-supervisor.ts | 71 ++++++++++++++++--
 3 files changed, 181 insertions(+), 15 deletions(-)

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Exercise the corrected result after issuing the replacement

This regression stops after confirming that a replacement exchange was issued, despite its name and the task acceptance criteria claiming that a corrected replacement is accepted. It never creates an allowed workspace change, writes a completed result to replacement.exchange.result_path, or returns that result through task advance, so a failure in the replacement acceptance/consumption path could leave the feature broken while this test still passes.

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[densmirnov]

Keep this PR for focused rework against current main (review baseline: ca07204, 0.7.9-beta.1).

The no-change implementation rejection still exists, while the proposed pre-apply rejection recovery is absent from the current supervisor.

Requested changes:

1. Update the branch against main and adapt the fix to the current acceptedApplication and already-applied handling.
2. Retire an exchange and permit replacement only when the supervisor can establish that the rejected result produced no apply effect. Preserve fail-closed behavior for partial application, stale results, and unrelated validation failures.
3. Prefer an existing structured rejection classification over matching a human-readable error message. If none exists, introduce only the narrow classification needed for this case.
4. Make the journal/exchange update recoverable across a crash or CAS failure. A retry must neither apply a result twice nor leave a rejected exchange permanently unusable.

Acceptance evidence:

• Reject a completed no-change result, obtain a fresh replacement packet, and successfully return a corrected implementation.
• Reject replay of the retired result.
• Cover CAS contention and interruption between journal persistence and exchange retirement.
• Demonstrate that partial-apply and other validation errors do not enter this recovery path.
• Run the focused supervisor/replacement tests and all checks required for the updated head.

This is a rework request, not an approval or a claim that the updated implementation has been tested.

[deus-agentplane]

Superseded by #5951 (07b7e86c9c3855288c31bff11e7488f5887512f5) and the current converged supervisor. Current main retires an implementation result rejected during application only after confirming Git, workspace, and route fingerprints did not change, records a failed supervisor operation, and emits an exact task advance --replacement --agent-json successor route. Replacement authority tests pass in the current-main targeted recovery suite at cc0516672e107f63083aa97aa4d8a8509e19d169. Closing this stale branch without merging.