Best possible solution:

Keep the generic embedded-runner hardening only if maintainers want this extra protection beyond the merged Discord fix, then land it with redacted real runtime proof and green checks.

Do we have a high-confidence way to reproduce the issue?

No high-confidence live reproduction was established for current main. Source inspection supports the generic risk: current main has only lastAssistant in payload assembly, while this PR distinguishes the current attempt assistant from stale transcript fallback.

Is this the best way to solve the issue?

Likely yes, subject to maintainer judgment and proof. Passing the current assistant into generic payload construction is a narrow solution for stale/final-text selection, but the original Discord user problem is already fixed by a channel-level recovery PR.

Acceptance criteria:

• OPENCLAW_VITEST_MAX_WORKERS=1 node scripts/run-vitest.mjs src/agents/pi-embedded-runner/run/payloads.test.ts src/agents/pi-embedded-runner/run/payloads.errors.test.ts extensions/discord/src/monitor/message-handler.process.test.ts
• pnpm check:changed
• Redacted live Discord or runtime proof showing a long/final assistant payload uses the completed final answer rather than a streamed preview fragment

What I checked:

• Live PR state and protected label: The live PR API shows this PR is open, authored by a contributor, and labeled maintainer, P1, and impact:message-loss, so conservative cleanup policy must not auto-close it. (6683bc5b37bf)
• Current main payload helper lacks current-assistant handoff: Current main's buildEmbeddedRunPayloads accepts lastAssistant but has no currentAssistant parameter, and canonical final-answer selection currently depends on more than one non-empty streamed assistant text. (src/agents/pi-embedded-runner/run/payloads.ts:181, 2c549ae20593)
• Current main runner call site passes only lastAssistant: The current runner call passes attempt.lastAssistant into buildEmbeddedRunPayloads without the PR's proposed current-attempt assistant distinction. (src/agents/pi-embedded-runner/run.ts:2591, 2c549ae20593)
• PR diff implements the generic handoff and selection change: The PR adds currentAssistant to the helper contract, passes currentAttemptAssistant ?? null from the runner, and selects assistantForPayload from the current assistant before falling back to transcript state. (src/agents/pi-embedded-runner/run/payloads.ts:182, 6683bc5b37bf)
• PR regression tests cover the intended edge cases: The diff adds focused tests for replacing an incomplete streamed preview with the structured final answer and for not letting a stale transcript assistant override a current one-chunk reply. (src/agents/pi-embedded-runner/run/payloads.test.ts:93, 6683bc5b37bf)
• Linked Discord issue is already fixed separately: The related Discord long-message issue was closed by merged fix(discord): recover truncated progress finals #82862; current main contains transcript-backed Discord final recovery coverage that delivers the full answer through deliverDiscordReply. (extensions/discord/src/monitor/message-handler.process.test.ts:1782, 549a0ea31310)

Likely related people:

• steipete: Authored the current payload-helper extraction commit and authored/merged the related Discord recovery fix that closed the linked long-message report. (role: feature owner and recent area contributor; confidence: high; commits: f45390416565, 549a0ea31310, b29152e3b951; files: src/agents/pi-embedded-runner/run/payloads.ts, src/agents/pi-embedded-runner/run/payloads.test.ts, extensions/discord/src/monitor/message-handler.process.test.ts)
• Galin Iliev: Recent history on run.ts shows adjacent embedded-attempt dispatch timing work at the payload call-site surface. (role: recent agent runner contributor; confidence: medium; commits: 91ae1a6c03bf; files: src/agents/pi-embedded-runner/run.ts)

Remaining risk / open question:

• The PR body provides focused tests and pnpm check:changed, but no redacted live runtime, channel, terminal, log, recording, screenshot, or linked artifact proof of the changed delivery path.
• The linked Discord truncation report is already fixed by fix(discord): recover truncated progress finals #82862, so maintainers need to decide whether this generic embedded-runner hardening is still worth landing as a follow-up.

Codex review notes: model gpt-5.5, reasoning high; reviewed against 2c549ae20593.