[juliusmarminge]

Problem

When Codex fails a turn with a codexErrorInfo code our generated schema doesn't list, the T3 run stays running forever with no error item. A ChatGPT-account Codex rejecting a model sends modelNotFound (reported case: gpt-5-codex). Both the error and the failed turn/completed notifications fail schema decode, and dispatchNotification drops them with "Dropped a Codex App Server notification that failed to decode". The adapter never sees the terminal event. This is not a registration race.

Reproduced on main (e5909e5) with the real dev server and the real codex-cli 0.163.0 app-server. Codex's stdout went through a filter that rewrites "codexErrorInfo":"other" to "modelNotFound", which matches the reporter's wire shape. Then t3 thread start <project> "say hi" --provider <that instance> --model gpt-5-codex. The thread was still running 50 s after the native turn/completed {status: "failed"}. Control: the same flow without the filter (code "other") ends as failed.

Change

CodexErrorInfo is a closed list of string codes plus a few structured variants. The generator now widens the string-code branch of the fetched upstream definition to any string (OpenStringEnumDefinitions in packages/effect-codex-app-server/scripts/generate.ts), and schema.gen.ts is regenerated from the same pinned ref. The structured variants stay typed. The only generated change is Schema.Literals([...]) → Schema.String in the 16 copies of CodexErrorInfo. Adapter consumers already compare codes as strings, so an unknown code is classed as a plain provider error and the run fails with Codex's message.

Scope and approval

Fixes #28032

Verification

• New test fails the turn when Codex reports an error info the schema does not list (CodexAdapterV2.test.ts). It replays error (willRetry: false) then a failed turn/completed, both with codexErrorInfo: "modelNotFound". On main it fails with expected undefined to equal 'failed'; it passes on this branch. With "other" it passes on main too, so it isolates the unlisted code.
• CodexAdapterV2.test.ts 123/123, packages/effect-codex-app-server tests pass. vp run check:changed passes: format, lint, knip, typecheck of 4 packages, tests.
• node scripts/generate.ts reproduces the committed generated files (apart from the generator's existing 2-line header).
• Server-only fix with no visible surface, so there's no capture matrix. Runtime transcript from the real dev server and real Codex app-server, using the filter above:

	Before (main e5909e5)	After (65c7c6a)
native error / turn/completed	modelNotFound / failed	modelNotFound / failed
"Dropped a Codex App Server notification that failed to decode"	2 (one per notification)	0
T3 thread after native completion	status: running, activeRunId set, 50 s later	status: failed, activeRunId: null; thread start --wait exits 1 with Codex's message

# before
2026-10-31T07:49:25.297Z incoming error          codexErrorInfo="modelNotFound"
2026-10-31T07:49:25.310Z incoming turn/completed codexErrorInfo="modelNotFound" status=failed
[07:49:25.299] WARN Dropped a Codex App Server notification that failed to decode
[07:49:25.310] WARN Dropped a Codex App Server notification that failed to decode
# thread show at 07:50:15: {'status': 'running', 'activeRunId': 'run:thread:mcp%3Aaf9fcc0a-…:ordinal:1', 'itemCount': 3}
# after
{"status":"failed","reply":null,"error":"{\"error\":{\"code\":\"model_not_found\",\"message\":\"unknown provider for model gpt-5-codex\",…}}"}
# thread show: {'status': 'failed', 'activeRunId': None, 'itemCount': 3}

Filter used as the Codex instance's binary path (scratch, not committed):

#!/usr/bin/env bash
exec codex "$@" | sed -u 's/"codexErrorInfo":"other"/"codexErrorInfo":"modelNotFound"/g'

Not checked: a live ChatGPT-account Codex. The VM routes Codex through an API proxy, so the failure text above is the proxy's instead of "The 'gpt-5-codex' model is not supported when using Codex with a ChatGPT account." The decode path is the same.

Claude Opus 5.5 (issue lead, red test, implementation) and GPT-6.1 Sol (review) in Claude Code / Codex, through T3 Code.

🤖 Generated with Claude Code

[macroscopeapp]

Approvability

Verdict: Approved at 65c7c6a

Macroscope's review found this PR approvable — Unknown Codex error codes can reach existing failure handling instead of leaving failed turns running. The change is limited to error-code decoding and preserves existing turn-status and retry rules.

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[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	5.0 KiB	5.0 KiB	−6 B (−0.1%)	6.8 KiB	✅
Codex	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Codex	Live turn WebSocket wire	1.3 KiB	1.2 KiB	−6 B (−0.5%)	2.0 KiB	✅
Codex	Live turn WebSocket decoded	21.6 KiB	21.6 KiB	0 B (0.0%)	24.4 KiB	✅
Codex	Live turn messages	2	2	0 (0.0%)	8	✅
Claude	Total thread wire	5.0 KiB	5.0 KiB	+29 B (+0.6%)	6.8 KiB	✅
Claude	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Claude	Live turn WebSocket wire	1.2 KiB	1.3 KiB	+29 B (+2.3%)	2.0 KiB	✅
Claude	Live turn WebSocket decoded	21.9 KiB	21.9 KiB	+41 B (+0.2%)	24.4 KiB	✅
Claude	Live turn messages	1	2	+1 (+100.0%)	8	✅

Baseline: 1aa46d0 · PR result: 65c7c6a · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 108.5 KiB
• Claude decoded thread snapshot: 108.8 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[coderabbitai]

No actionable comments were generated in the recent review.

Recent review info

Run configuration

• Source mode: Auto
• Repository: pingdotgg/t3code
• Branch: fix/issue-28032
• File: .coderabbit.config.ts
• Commit: 65c7c6a
• Layers: Repository TS config
• Review profile: CHILL
• Plan: Team
• Run ID: 4b5cbc86-c684-439c-acdb-a4499efb58a0

Commits

Reviewing files that changed from the base of the PR and between 1aa46d0 and 65c7c6a.

Files ignored due to path filters: 1

• packages/effect-codex-app-server/src/_generated/schema.gen.ts is excluded by !**/_generated/**

Files selected for processing: 2

• apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.test.ts
• packages/effect-codex-app-server/scripts/generate.ts

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 6 remain after this review.

Walkthrough

The generated CodexErrorInfo schema now accepts unlisted string values unless an override applies. A Codex adapter replay test covers a failed turn with modelNotFound and checks its terminal status and error message.

Changes: Codex error decoding

Layer / File(s)	Summary
Open the error schema and test failed-turn replay packages/effect-codex-app-server/scripts/generate.ts, apps/server/src/orchestration-v2/Adapters/CodexAdapterV2.test.ts	The generator replaces constrained string variants in CodexErrorInfo with an unconstrained string schema when no definition override applies. The replay test checks that a turn with modelNotFound ends as failed and retains the provider error message.

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix · Severity of issue fixed: Medium

Suggested reviewers: maria-rcks

Merge Risk: Minimal · up to 65c7c

Unknown Codex error codes can now produce failed turns with the provider message. No merge-blocking issue remains identified.

Pre-merge checks: 4

Check name	Status	Explanation
Title check		The title clearly and concisely describes the primary fix: Codex turns with unlisted error codes now reach a failed state instead of remaining running.
Description check		The description includes the required Problem, Change, Scope and approval, and Verification sections. It provides detailed reproduction steps, implementation details, issue scope, test results, runtim…
Linked Issues check		Issue #28032 requires unsupported Codex model turns to reach a failed terminal state and retain Codex's error message. The PR widens the generated CodexErrorInfo string branch to accept unlisted cod…
Out of Scope Changes check		The changed generator logic, generated schema, and regression test directly support issue #28032. The changes preserve typed structured variants and do not introduce unrelated behavior or surface chan…

Full details: Description check

Explanation

The description includes the required Problem, Change, Scope and approval, and Verification sections. It provides detailed reproduction steps, implementation details, issue scope, test results, runtime evidence, and known verification limits.

Full details: Linked Issues check

Explanation

Issue #28032 requires unsupported Codex model turns to reach a failed terminal state and retain Codex's error message. The PR widens the generated CodexErrorInfo string branch to accept unlisted codes, updates the generated schema, and adds a regression test for modelNotFound on both error and failed turn/completed notifications. The reported test and package checks pass. The excluded generated path prevents direct inspection of that file, but the change summary and generator update establish the intended generated change.

Full details: Out of Scope Changes check

Explanation

The changed generator logic, generated schema, and regression test directly support issue #28032. The changes preserve typed structured variants and do not introduce unrelated behavior or surface changes.

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