Every write to the per-sign-in Codex memory checked the account digest,
but the reads did not. A credential reconnected to another ChatGPT
account therefore tried the old account's working model first, sorted
by its refusals and trusted its model list, until the first write
rebound the entry, and the vision gate kept answering from the old
account in the meantime.
The client reads (working model, refusals, model list) now take the
credential and treat an entry learned under another account as empty.
The vision gate holds no account id, so the connect routes rebind the
entry and the disconnect routes drop it, and the gate reads the entry
as its process last bound it.
A fixed preference list goes stale at every retirement: when GPT-5.5
retired for ChatGPT sign-in on 2026-10-14, every model the shipped list
named was refused and Codex answered 503 until a release changed it. The
working model also sat in one slot for the whole process, so two sign-ins
on different plans overwrote each other's model and the vision gate read
whichever had answered last.
The client now reads the models the account is offered the way the Codex
CLI does (GET /backend-api/codex/models?client_version=..., same sign-in
as the responses call; shape from codex-rs/protocol/src/openai_models.rs)
and walks: CODEX_MODEL first; our preference order kept to what is
offered; the other offered models in the list's priority order, leaving
out hidden, specialist and frontier-tier entries; the rest of our order
last, so the walk never holds fewer models than before. With
CODEX_MODEL_FALLBACK_CHAIN set the order is the operator's and the list is
not read.
The list is a hint, never a gate. The read goes through safeFetch with a
5 s bound and a 4 MiB cap, is shared by concurrent requests, cached per
sign-in for an hour, and a failed read waits ten minutes. Any failure
leaves the static walk, one ai.codex.models_unreadable warning per sign-in
reports it, and each request that builds the walk annotates a pinned
codex.models.* shape.
The working model, refused models and the list are kept per stored
credential (a person's connection, or the operator-shared central one),
bounded by TTL and a 1000-entry LRU, with a digest of the account id so a
credential reconnected to another account starts empty. A model the list
offered that then answers model_not_found goes to the back of that
sign-in's line for six hours. When the list names a model's input
modalities, the Codex vision gate reads them; otherwise the model family
decides, as before.
Refs #1287
Output of `node scripts/strip-planning-tags.mjs --write`: 3,157 comment
lines in 1,308 files lose the work-item identifier at their head. Release
versions and issue references stay; nothing outside comment text
changes, which the script checks per file against a comment-free
printout. healthlog/no-planning-tags is enabled at error level with this
commit, so the tree it lands on is clean.
Phase C1 (v1.4.15) — slug-drift defence per Marc's hard mandate:
"Die Integration des Slug Drift Risiko darf halt immer überhaupt nicht
sein." ("Slug-drift risk must NEVER happen.")
Background: the ChatGPT-Codex backend rotates its allow-list silently.
v1.4.7..v1.4.13 lost a week to chasing the rotation manually
(`gpt-5-codex` → `gpt-5.3-codex`). A single hard-coded `CODEX_MODEL`
flips invalid the moment upstream rotates it.
Solution — the client now walks an ordered fallback chain on every
fresh request series and caches the first slug that returns 200 +
`response.completed` for 1 hour. Subsequent requests skip the chain
walk entirely on a cache hit.
Spec: extends `docs/codex-protocol-spec.md` with new §7b documenting
the chain semantics, cache TTL, walk triggers (400 + "not supported
when using Codex with a ChatGPT account" / `model_not_found` /
"does not exist" / 404), non-walk responses (5xx, 429, 401-with-
refresh, `invalid_prompt`), and the all-failed structured-503 error
shape. Per Marc's v1.4.6 hard rule ("read source-of-truth before
iterating; no more 6-iteration line-fixes"), the spec was extended
FIRST and the implementation cross-referenced against it.
Implementation:
- New `src/lib/ai/codex-slug-cache.ts` — process-local positive
cache. Single-slot Map (per-account scoping is a one-line change
when v1.4.16 multi-tenant rolls out). 1 h TTL. `getCachedCodexSlug`
auto-evicts expired entries on read.
- Rewritten `CodexClient.generateCompletion()` — walks the chain
`[cached?, ...slugChain]` in order. On 401 → refresh + retry SAME
slug (auth ≠ slug-state). On 400/404 with rejection body → drop
cache, walk to next. On 5xx/429 → propagate immediately (walking
won't help). On all-rejected → throw structured 503 with
`attempted[]` list, `httpStatus: 503`, message "AI provider
unreachable — all configured Codex slugs were rejected".
- `CodexAttemptDiagnostics` exposes `{ attempted, cacheState,
workingSlug }` for Wide-Event annotations the route can read via
`client.getLastDiagnostics()`.
- `CODEX_MODEL_FALLBACK_CHAIN` env override (comma-separated). When
`CODEX_MODEL` is also set, it folds into chain position 0; the
default chain (`gpt-5.3-codex` → `gpt-5-codex` → `gpt-5` →
`gpt-4o`) survives behind it. Stable de-dup.
Tests: +20 across 2 new files.
`codex-slug-cache.test.ts` (7 tests) — TTL-edge boundaries,
invalidation, replacement semantics.
`codex-slug-fallback.test.ts` (13 tests) — cold-cache happy path,
walk on canonical 400 body, walk on `model_not_found`, walk on 404,
no-walk on 500/429/401, all-rejected → 503-with-attempted-list,
cache-hit shortcut, cache invalidation on rejection, isSlugRejection
body classifier, loadFallbackChain env-pin merge.
The 5 existing `codex-client.test.ts` cases continue to pass without
edit — the new `slugChain` constructor parameter is opt-in and the
single-slug behaviour reduces to chain length 1.
Tests: 1028 → 1048 unit pass (+20). Typecheck clean for AI files.
Lint clean.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Marc-André Bombeck