Codex DM should not send speaker:null to log_event

[100yenadmin]

Summary

During the 2026-06-01 built WorldOS.app Codex-DM short playtest, the second player move recovered but exposed a model/tool-contract defect: Codex first called log_event with speaker: null, which the engine rejected before the model retried without speaker.

Evidence

• Evidence folder: /Volumes/LEXAR/Codex/worldos-built-app-playtest/codex-app-short-20260601T022114/
• App code SHA reported by harness: c3dfee6
• Minted run: play-state/play-20260531192201
• Tool trace: play-state/play-20260531192201/codex-provider/codex-dm.stdout.jsonl
• Final proof still passed diagnostically:
  • 06-after-move-2-dm-response.png
  • 06-session-surface-after-move-2.json
  • 06-chat-after-move-2.jsonl

The failed tool result was:

Error executing tool log_event: 1 validation error for log_eventArguments
speaker
  Input should be a valid string [type=string_type, input_value=None, input_type=NoneType]

The model retried with no speaker, narration landed, and the player-facing session recovered. This is not a release-stopping failure from this run, but it adds turn latency/noise and could become visible if retries fail.

Acceptance Criteria

• Codex DM prompts/wrapper/tool instructions avoid emitting speaker: null for narration events.
• A repeat built-app or RRI Codex-DM run shows no speaker:null / Pydantic validation failure in codex-dm.stdout.jsonl.
• The fix preserves engine authority: narration still writes through log_event; the GUI remains a reader plus /move submitter.

[100yenadmin]

Fixed on PR #475 at commit 500c379 / prior e79144d boundary changes. Final exact-head built-app evidence: /Volumes/LEXAR/Codex/worldos-built-app-playtest/codex-app-final-20260601T033714/05-provider-trace-summary.json shows log_event_speaker_null_argument_ids: []; the accepted move resolved with chat roles dm, player, dm. Leaving open until #475 merges to main.

[100yenadmin]

Closed after PR #475 merged. The issue's acceptance was proven in codex-app-final-20260601T033714 / codex-app-headproof-20260601T043909: no speaker:null log_event calls, accepted move resolved, and chat roles remained dm, player, dm. #479 stays open for the broader provider trace-noise issue.