Best possible solution:

Preserve heartbeat model selection as run-scoped while ensuring session status/listing derives any missing context window from the preserved runtime model rather than from the latest heartbeat transcript.

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

Yes. Configure a heartbeat model that differs from the primary model, run a heartbeat on a shared session, and inspect session_status or the session row; current main writes the heartbeat provider/model/context window into shared runtime fields.

Is this the best way to solve the issue?

No. The preservation flag is the right boundary, but the missing-context branch should also cover the status/listing transcript fallback path or add status-level regression coverage before merge.

Full review comments:

• [P2] Preserve context identity when contextTokens are missing — src/agents/command/session-store.ts:124
  When a preserved entry has a model but no cached contextTokens, this branch intentionally leaves contextTokens unset. Session rows then treat runtime fields with missing context as needing transcript fallback, and readRecentSessionUsageFromTranscript can replace the displayed model/provider with the latest heartbeat transcript, so the bleed can still show up in session_status for older entries.
  Confidence: 0.86

Overall correctness: patch is incorrect
Overall confidence: 0.86

Acceptance criteria:

• pnpm test src/agents/command/session-store.test.ts
• pnpm test src/agents/openclaw-tools.session-status.test.ts
• pnpm test src/gateway/session-utils.fs.test.ts
• pnpm exec oxfmt --check --threads=1 src/agents/agent-command.ts src/agents/command/session-store.ts src/agents/command/session-store.test.ts src/agents/openclaw-tools.session-status.test.ts src/gateway/session-utils.ts docs/gateway/heartbeat.md CHANGELOG.md

What I checked:

• Current main persists heartbeat runtime model: On current main, updateSessionStoreAfterAgentRun derives provider/model/contextTokens from run metadata and unconditionally writes them to the session entry, while agent-command only suppresses lastInteractionAt for heartbeat runs. (src/agents/command/session-store.ts:77, 2244ba87b362)
• PR preservation path: The PR adds preserveRuntimeModel and uses it for heartbeat runs so existing runtime model fields are not overwritten by the heartbeat model. (src/agents/command/session-store.ts:117, 42a00dcf385d)
• Remaining status fallback issue: Current session row construction switches to transcript model identity whenever runtime fields exist but contextTokens or totalTokens are missing; recent transcript usage keeps the latest assistant message model/provider, which can be the heartbeat model. (src/gateway/session-utils.ts:1549, 2244ba87b362)
• Related implementation duplicate: Related PR fix #75452: Heartbeat per-turn model override persists after turn completes #75567 was closed unmerged, so this PR remains the active implementation candidate for linked issue Heartbeat per-turn model override persists after turn completes (2026.4.29) #75452.
• Read-only verification only: No tests were run because this review was explicitly read-only and the checkout remained clean after inspection. (2244ba87b362)

Likely related people:

• steipete: Recent blame and commit history show repeated maintenance of the central session-store, agent-command, heartbeat docs, and session status/listing paths involved in this behavior. (role: recent maintainer; confidence: high; commits: d678bcfcc7d0, f7ed29e11812, 59fb9e5ca7fe; files: src/agents/command/session-store.ts, src/agents/agent-command.ts, src/gateway/session-utils.ts)
• bittoby: Recent merged work touched current-session resolution and session-status tests, which are the user-visible status surfaces affected by the remaining edge case. (role: adjacent session/status maintainer; confidence: medium; commits: d5ad90f7ec7c; files: src/agents/openclaw-tools.session-status.test.ts, src/agents/tools/session-status-tool.ts)

Remaining risk / open question:

• The PR has a concrete correctness gap for sessions that have a preserved runtime model but no cached contextTokens; status/listing can still display the heartbeat model from transcript fallback.

Codex review notes: model gpt-5.5, reasoning high; reviewed against 2244ba87b362.