fix(runner): cold-replay stopgaps — result caps, resume frame, arg parsing

[mmabrouk]

Two production turns failed on 2026-07-07 because the runner cold-replays the conversation as flattened text every turn. Turn c6de1865 needed three approval rounds for one curl: each fresh model rebuilt the arguments from the text replay and drifted the approval key. Turn 6d34b1ea ran five rounds and executed zero commits: the resume prompt re-presented the stale user command as if just spoken, so each fresh model restarted the whole task, and one 30-60 KB tool dump filled the 24K window and evicted the original goal.

Full analysis: docs/design/agent-workflows/projects/approval-boundary/cold-replay-failure-report.md. Session-based continuation is the real fix and lands next; these are the cheap repairs to the text-replay path, which stays as the fallback after sessions.

Replay framing, before/after

Before (approval resume, no new user text):

Conversation so far:
...
[user APPROVED commit_revision; the call has NOT run yet. ...]

Continue the conversation. The user now says:
search for tools and add them if needed use the skill   <- stale, restarts the task

After:

Conversation so far:
user: search for tools and add them if needed use the skill   <- stays in history position
...
[user APPROVED commit_revision; the call has NOT run yet. ...]

The user has responded to the pending approval above. If a call is marked APPROVED and not yet run, execute exactly that call now with the same arguments; do not restart the task. If it was DENIED, continue without it.

The four changes (all services/runner)

1. Per-result cap + bigger window (transcript.ts): each rendered tool RESULT body caps at 4,000 chars with an explicit [... N chars omitted] marker. Tool CALL args are never capped (the resume nudge says "with the same arguments"). Default AGENTA_AGENT_HISTORY_MAX_CHARS raised 24,000 -> 100,000, still env-overridable.
2. Resume closing frame (transcript.ts): when an unresolved approved call is newer than the last user text, the closing frame becomes the execute-the-approved-call instruction above instead of the stale command. Normal new-user-message turns are unchanged.
3. normalizeJsonish hardening (responder.ts): tolerates up to three stray trailing }/] on stringified JSON args (the round-5 shape), so the honest re-issue matches the stored approval key. Non-JSON strings keep their literal value.
4. Replay observability (transcript.ts + run-plan.ts): one [HITL] cold replay: log line per replay with transcript length before/after the tail slice, fully evicted message count, pending-nudge presence, resume-frame flag, and turnText length.

Deferred to the session work

• Runner-side execution of approved calls (keep-alive slice 2 answers the parked permission RPC directly).
• Name-level approval-key fallback matching (same).
• Session/keep-alive machinery (its own project).
• get_revision platform op (build-kit backlog).
• Frontend changes.

Tests: pnpm test 620/620 green, pnpm run typecheck green. Design doc: docs/design/agent-workflows/projects/cold-replay-stopgaps/.

https://claude.ai/code/session_01AumZJ9xRd4XYNHThqy4rTv

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Project	Deployment	Actions	Updated (UTC)
agenta-documentation	Ready	Preview, Comment	Jul 7, 2026 8:59pm

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