diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7c8a9ff923..3284105053 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -126,6 +126,7 @@ jobs:
       - run: npm run check:route-validation:t06
       - run: npm run check:any-budget:t11
       - run: npm run check:provider-consistency
+      - run: npm run check:model-lifecycle
       - run: npm run check:fetch-targets
       - run: npm run check:deps
       - run: npm run check:file-size
diff --git a/.github/workflows/quality.yml b/.github/workflows/quality.yml
index 9047db295e..c0efa13a2f 100644
--- a/.github/workflows/quality.yml
+++ b/.github/workflows/quality.yml
@@ -273,7 +273,7 @@ jobs:
             migration-numbering public-creds db-rules known-symbols
             route-guard-membership test-discovery test-runner-api
             mutation-test-coverage any-budget:t11 build-scope pack-policy
-            complexity-ratchets
+            complexity-ratchets model-lifecycle
             cycles lockfile duplication dead-code type-coverage compression-budget
             # #8781: open-sse workspace typecheck gate — the workspace imports @/ which
             # escapes to src/ via undeclared path aliases. See check-open-sse-typecheck.mjs.
diff --git a/changelog.d/fixes/11507-catalog-hygiene.md b/changelog.d/fixes/11507-catalog-hygiene.md
new file mode 100644
index 0000000000..7cf735e6d1
--- /dev/null
+++ b/changelog.d/fixes/11507-catalog-hygiene.md
@@ -0,0 +1 @@
+- **fix(autoCombo,sse):** catalog hygiene — the static task-fitness table no longer ranks retired models above live ones (dead rows dropped, patterns matched on segment boundaries), the 7 deprecation aliases that forwarded to retired or non-existent models now point at the vendors' published replacements, an alias is no longer rewritten when the serving provider offers the id as-is, and a new `check:model-lifecycle` gate diffs both tables against a vendor lifecycle snapshot ([#11507](https://github.com/diegosouzapw/OmniRoute/pull/11507))
diff --git a/config/quality/model-lifecycle.json b/config/quality/model-lifecycle.json
new file mode 100644
index 0000000000..40ac870f9f
--- /dev/null
+++ b/config/quality/model-lifecycle.json
@@ -0,0 +1,658 @@
+{
+  "//": "Vendor model lifecycle snapshot (#11503). Hand-curated from the first-party deprecation pages listed in `sources`; regenerate with `npm run quality:refresh-model-lifecycle`. Consumed by `npm run check:model-lifecycle` and by the FITNESS_TABLE / BUILT_IN_ALIASES regression tests. `replacement` is null where the vendor publishes none — never invent one.",
+  "generatedAt": "2026-08-25",
+  "sources": [
+    "https://platform.claude.com/docs/en/about-claude/model-deprecations",
+    "https://developers.openai.com/api/docs/deprecations",
+    "https://ai.google.dev/gemini-api/docs/deprecations",
+    "https://docs.x.ai/docs/models",
+    "https://console.groq.com/docs/deprecations"
+  ],
+  "allowedRetiredInCatalog": [
+    "chatgpt-4o-latest",
+    "claude-3-5-sonnet-20241022",
+    "claude-3-7-sonnet-20250219",
+    "google/gemini-2.0-flash",
+    "gpt-4-0125-preview",
+    "openai/gpt-5.2-codex"
+  ],
+  "allowedRetiredInCatalog_note": "TODO(#11503): ratchet to burn down. Each id is retired by its vendor but still routable from the provider catalog. Removing a catalog row or adding a BUILT_IN_ALIASES forward is a maintainer call (some aggregators still serve these ids), so they are allowlisted here rather than silently dropped. Delete an entry as soon as it is forwarded or removed; never add one without a tracking issue.",
+  "retired": {
+    "claude-opus-4-1-20250805": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2026-08-05",
+      "replacement": "claude-opus-4-8"
+    },
+    "claude-opus-4-20250514": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2026-06-15",
+      "replacement": "claude-opus-4-8"
+    },
+    "claude-sonnet-4-20250514": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2026-06-15",
+      "replacement": "claude-sonnet-4-6"
+    },
+    "claude-3-7-sonnet-20250219": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2026-02-19",
+      "replacement": "claude-sonnet-4-6"
+    },
+    "claude-3-5-haiku-20241022": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2026-02-19",
+      "replacement": "claude-haiku-4-5-20251001"
+    },
+    "claude-3-haiku-20240307": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2026-04-20",
+      "replacement": "claude-haiku-4-5-20251001"
+    },
+    "claude-3-opus-20240229": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2026-01-05",
+      "replacement": "claude-opus-4-8"
+    },
+    "claude-3-5-sonnet-20240620": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2025-10-28",
+      "replacement": "claude-sonnet-4-6"
+    },
+    "claude-3-5-sonnet-20241022": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2025-10-28",
+      "replacement": "claude-sonnet-4-6"
+    },
+    "claude-3-sonnet-20240229": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2025-07-21",
+      "replacement": "claude-sonnet-4-6"
+    },
+    "claude-2.0": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2025-07-21",
+      "replacement": "claude-opus-4-8"
+    },
+    "claude-2.1": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": "2025-07-21",
+      "replacement": "claude-opus-4-8"
+    },
+    "claude-1.0": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "claude-1.1": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "claude-1.2": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "claude-1.3": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "claude-instant-1.0": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "claude-instant-1.1": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "claude-instant-1.2": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "claude-mythos-preview": {
+      "vendor": "anthropic",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": "claude-mythos-5"
+    },
+    "gpt-5-codex": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5.1-codex": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5.1-codex-max": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5.1-codex-mini": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5.2-codex": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5-chat-latest": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5.1-chat-latest": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5.2-chat-latest": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5.3-chat-latest": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o1-mini": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o1-preview": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "chatgpt-4o-latest": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "codex-mini-latest": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4.5-preview": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "computer-use-preview": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "computer-use-preview-2025-03-11": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o3-deep-research": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o4-mini-deep-research": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4o-search-preview-2025-03-11": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4o-mini-search-preview-2025-03-11": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "dall-e-2": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "dall-e-3": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-0314": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-0125-preview": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-turbo-preview": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-32k": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-32k-0613": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-32k-0314": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-vision-preview": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "text-moderation-latest": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-3.5-turbo-0613": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-3.5-turbo-16k-0613": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4o-realtime-preview": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4o-audio-preview": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4o-mini-audio-preview": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4o-mini-realtime-preview": {
+      "vendor": "openai",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-3.5-turbo-0125": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-3.5-turbo": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-0613": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-1106-preview": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-turbo": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4-turbo-2024-04-09": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4.1-nano": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4.1-nano-2025-04-14": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4o-2024-05-13": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-image-1": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o1-2024-12-17": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o1": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o1-pro-2025-03-19": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o1-pro": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o3-mini-2025-01-31": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o3-mini": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o4-mini-2025-04-16": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o4-mini": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-3.5-turbo-instruct": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "babbage-002": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "davinci-002": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-3.5-turbo-1106": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5-2025-08-07": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5-mini-2025-08-07": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5-nano-2025-08-07": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-5-pro-2025-10-06": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o3-2025-04-16": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "o3-pro-2025-06-10": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-realtime": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-audio": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4o-audio": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-4o-realtime": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-image-1-mini": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gpt-image-1.5": {
+      "vendor": "openai",
+      "status": "retiring",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gemini-2.0-flash": {
+      "vendor": "google",
+      "status": "retired",
+      "retiredOn": "2026-06-01",
+      "replacement": null
+    },
+    "gemini-2.0-flash-001": {
+      "vendor": "google",
+      "status": "retired",
+      "retiredOn": "2026-06-01",
+      "replacement": null
+    },
+    "gemini-2.0-flash-lite": {
+      "vendor": "google",
+      "status": "retired",
+      "retiredOn": "2026-06-01",
+      "replacement": null
+    },
+    "gemini-2.0-flash-lite-001": {
+      "vendor": "google",
+      "status": "retired",
+      "retiredOn": "2026-06-01",
+      "replacement": null
+    },
+    "gemini-1.5-pro": {
+      "vendor": "google",
+      "status": "retired",
+      "retiredOn": "2025-09-29",
+      "replacement": null
+    },
+    "gemini-1.5-flash": {
+      "vendor": "google",
+      "status": "retired",
+      "retiredOn": "2025-09-29",
+      "replacement": null
+    },
+    "gemini-1.5-flash-8b": {
+      "vendor": "google",
+      "status": "retired",
+      "retiredOn": "2025-09-29",
+      "replacement": null
+    },
+    "gemini-robotics-er-1.5-preview": {
+      "vendor": "google",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gemini-3-pro-preview": {
+      "vendor": "google",
+      "status": "retired",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "gemini-robotics-er-1.6-preview": {
+      "vendor": "google",
+      "status": "retiring",
+      "retiredOn": "2026-08-31",
+      "replacement": null
+    },
+    "grok-voice-think-fast-1.0": {
+      "vendor": "xai",
+      "status": "deprecated",
+      "retiredOn": null,
+      "replacement": null
+    },
+    "llama3-8b-8192": {
+      "vendor": "groq",
+      "status": "retired",
+      "retiredOn": "2025-08-30",
+      "replacement": "llama-3.1-8b-instant"
+    },
+    "llama3-70b-8192": {
+      "vendor": "groq",
+      "status": "retired",
+      "retiredOn": "2025-08-30",
+      "replacement": "llama-3.3-70b-versatile"
+    },
+    "llama-3.1-8b-instant": {
+      "vendor": "groq",
+      "status": "retiring",
+      "retiredOn": "2026-08-16",
+      "replacement": "openai/gpt-oss-20b"
+    },
+    "codestral-2405": {
+      "vendor": "mistral",
+      "status": "retired",
+      "retiredOn": "2025-06-16",
+      "replacement": "codestral-2508"
+    }
+  }
+}
diff --git a/docs/architecture/QUALITY_GATES.md b/docs/architecture/QUALITY_GATES.md
index 42d3ee7908..9c4414e89f 100644
--- a/docs/architecture/QUALITY_GATES.md
+++ b/docs/architecture/QUALITY_GATES.md
@@ -64,6 +64,7 @@ Runs on every PR to `main`. Blocks merge on failure.
 | `check:route-validation:t06`   | Zod schemas present on all routes (Tier 6 policy)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | Yes                                      |
 | `check:any-budget:t11`         | `@ts-expect-error // any` count does not exceed budget (Tier 11 catraca)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | Yes                                      |
 | `check:provider-consistency`   | Every provider in `providers.ts` has a matching entry in `providerRegistry.ts` (and vice-versa, within the allowlist)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Yes                                      |
+| `check:model-lifecycle`        | The two hand-maintained routing tables do not point at retired models (#11503): `FITNESS_TABLE` (`taskFitness.ts`) scores no routable retired id, every `BUILT_IN_ALIASES` target is a live catalog model, and every retired id the catalog still routes is either forwarded or listed in `allowedRetiredInCatalog`. Offline — compares against the vendor snapshot `config/quality/model-lifecycle.json`, refreshed by hand with `npm run quality:refresh-model-lifecycle` (network; not wired into CI). `allowedRetiredInCatalog` is a burn-down ratchet: add an entry only with a tracking issue.                    | Yes                                      |
 | `check:fetch-targets`          | Every `fetch("/api/...")` in client-side `src/` resolves to a real `route.ts`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | Yes                                      |
 | `check:deps`                   | All `npm install`-able deps across every `package.json` in the repo are in `dependency-allowlist.json`; new unpinned or slopsquatted packages flagged                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Yes                                      |
 | `audit:deps`                   | `npm audit` (root + electron) — no high/critical advisories (overlaps osv `check:vuln-ratchet`; see Rationalization Backlog)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | Yes                                      |
diff --git a/open-sse/handlers/chatCore/modelLifecyclePolicy.ts b/open-sse/handlers/chatCore/modelLifecyclePolicy.ts
index 698e3c5c8e..ed2ed9513f 100644
--- a/open-sse/handlers/chatCore/modelLifecyclePolicy.ts
+++ b/open-sse/handlers/chatCore/modelLifecyclePolicy.ts
@@ -40,13 +40,15 @@ function getModelLifecycleError({
 export function checkLifecycle(provider: string, model: string, log?: LifecycleLogger) {
   return getModelLifecycleError({
     provider,
-    model: resolveModelAlias(model),
+    // #11503: pass the provider so a globally deprecated id this provider still serves
+    // under its original name is left alone instead of rewritten into a 404.
+    model: resolveModelAlias(model, provider),
     log,
   });
 }
 
 export function resolveLifecycle(provider: string, model: string, log?: LifecycleLogger) {
-  const resolvedModel = resolveModelAlias(model);
+  const resolvedModel = resolveModelAlias(model, provider);
   if (resolvedModel !== model) {
     log?.info?.("ALIAS", `Model alias applied: ${model} → ${resolvedModel}`);
   }
diff --git a/open-sse/services/autoCombo/__tests__/autoCombo.test.ts b/open-sse/services/autoCombo/__tests__/autoCombo.test.ts
index 96c2dbc42e..ba4cce5b83 100644
--- a/open-sse/services/autoCombo/__tests__/autoCombo.test.ts
+++ b/open-sse/services/autoCombo/__tests__/autoCombo.test.ts
@@ -71,7 +71,7 @@ describe("Scoring", () => {
 
 describe("Task Fitness", () => {
   it("should return fitness score for known model+task", () => {
-    const score = getTaskFitness("claude-sonnet", "coding");
+    const score = getTaskFitness("o3", "coding");
     expect(score).toBeGreaterThan(0.5);
   });
 
@@ -494,7 +494,7 @@ describe("LKGP Strategy", () => {
 
 describe("Task Fitness Resolution Chain", () => {
   it("getTaskFitness should return static table score for known models", () => {
-    const score = getTaskFitness("claude-sonnet", "coding");
+    const score = getTaskFitness("o3", "coding");
     expect(score).toBe(0.95);
   });
 
@@ -514,7 +514,7 @@ describe("Task Fitness Resolution Chain", () => {
   });
 
   it("getTaskFitnessWithSource should return source='fitness_table' for known static models", () => {
-    const result = getTaskFitnessWithSource("claude-sonnet", "coding");
+    const result = getTaskFitnessWithSource("o3", "coding");
     expect(result).toEqual({ score: 0.95, source: "fitness_table" });
   });
 
@@ -574,7 +574,7 @@ describe("Task Fitness Resolution Chain", () => {
   });
 
   it("getTaskFitnessWithSource returns 'fitness_table' for statically known models", () => {
-    const result = getTaskFitnessWithSource("claude-sonnet", "review");
+    const result = getTaskFitnessWithSource("o3", "review");
     expect(result.source).toBe("fitness_table");
     expect(result.score).toBe(0.92);
   });
@@ -595,15 +595,15 @@ describe("Task Fitness DB Resolution Chain", () => {
   it("falls back to static FITNESS_TABLE when DB is not initialized", () => {
     // In the test environment, DB is typically not initialized,
     // so getTaskFitness should fall through to the static table
-    const score = getTaskFitness("claude-sonnet", "coding");
-    // Static table has claude-sonnet → 0.95 for coding
+    const score = getTaskFitness("o3", "coding");
+    // Static table has o3 → 0.95 for coding
     expect(score).toBe(0.95);
   });
 
   it("falls back to static FITNESS_TABLE for review task type", () => {
-    const score = getTaskFitness("claude-opus", "review");
-    // Static table has claude-opus → 0.95 for review
-    expect(score).toBe(0.95);
+    const score = getTaskFitness("gemini-2.5-pro", "review");
+    // Static table has gemini-2.5-pro → 0.93 for review
+    expect(score).toBe(0.93);
   });
 
   it("falls back to wildcard boosts when no static entry exists and DB unavailable", () => {
@@ -634,14 +634,14 @@ describe("Task Fitness DB Resolution Chain", () => {
   });
 
   it("resolution chain: static table takes priority over wildcard for known models", () => {
-    // "claude-sonnet" is in the static table with coding=0.95
+    // "o3" is in the static table with coding=0.95
     // It does NOT match "coder" wildcard because the static table is checked first
-    const score = getTaskFitness("claude-sonnet", "coding");
+    const score = getTaskFitness("o3", "coding");
     expect(score).toBe(0.95); // From static table, NOT wildcard
   });
 
   it("getTaskFitnessWithSource identifies fitness_table as source for known models", () => {
-    const model = "claude-sonnet";
+    const model = "o3";
     const category = "coding";
 
     const result = getTaskFitnessWithSource(model, category);
@@ -650,14 +650,14 @@ describe("Task Fitness DB Resolution Chain", () => {
   });
 
   it("case insensitivity: model names are lowercased before lookup", () => {
-    const upperScore = getTaskFitness("CLAUDE-SONNET", "coding");
-    const lowerScore = getTaskFitness("claude-sonnet", "coding");
+    const upperScore = getTaskFitness("O3", "coding");
+    const lowerScore = getTaskFitness("o3", "coding");
     expect(upperScore).toBe(lowerScore);
   });
 
   it("case insensitivity: task types are lowercased before lookup", () => {
-    const upperScore = getTaskFitness("claude-sonnet", "CODING");
-    const lowerScore = getTaskFitness("claude-sonnet", "coding");
+    const upperScore = getTaskFitness("o3", "CODING");
+    const lowerScore = getTaskFitness("o3", "coding");
     expect(upperScore).toBe(lowerScore);
   });
 
diff --git a/open-sse/services/autoCombo/__tests__/fitness-table-hygiene-11503.test.ts b/open-sse/services/autoCombo/__tests__/fitness-table-hygiene-11503.test.ts
new file mode 100644
index 0000000000..87abe73f9b
--- /dev/null
+++ b/open-sse/services/autoCombo/__tests__/fitness-table-hygiene-11503.test.ts
@@ -0,0 +1,102 @@
+/**
+ * TDD regression for #11503: `FITNESS_TABLE` (resolution layer 4) was a hand-maintained
+ * table of version-less family patterns matched by `String.includes`, so it kept ranking
+ * models the vendors had already retired — and ranked them ABOVE live flagships it had
+ * never heard of. On `release/v3.8.51`, `openai/gpt-5.2-codex` (shut down 2026-07-23)
+ * scored 0.98 for `coding` via the `codex` row while `claude-fable-5-thinking-max` and
+ * `gpt-5.6-sol-xhigh` — both live — fell to the wildcard 0.5.
+ *
+ * Two changes are pinned here:
+ *  1. The table only carries VERSIONED rows that name a live catalog model. Retired
+ *     families (`codex`, `o1`, `mixtral`, `grok-4-fast`) and version-less family
+ *     patterns (`claude-sonnet`, `qwen`, `llama`, `gemini-pro`, …) are gone.
+ *  2. Matching is anchored to segment boundaries, so a row can no longer leak into an
+ *     id that merely contains its characters.
+ *
+ * An id the table does not know resolves to the wildcard baseline 0.5 — the documented
+ * neutral for "no evidence", never a quality claim.
+ */
+import { readFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import { describe, it, expect } from "vitest";
+import { getStaticFitnessTableScore } from "../taskFitness";
+import { REGISTRY } from "../../../config/providers/index.ts";
+
+const TASK_TYPES = ["coding", "review", "planning", "analysis", "debugging", "documentation"];
+
+const lifecycle = JSON.parse(
+  readFileSync(
+    fileURLToPath(new URL("../../../../config/quality/model-lifecycle.json", import.meta.url)),
+    "utf8"
+  )
+) as { retired: Record<string, { status: string }> };
+
+const retiredIds = new Set(
+  Object.entries(lifecycle.retired)
+    .filter(([, entry]) => entry.status === "retired")
+    .map(([id]) => id.toLowerCase())
+);
+
+/** Every model id the provider catalog can route, including per-model aliases. */
+function collectCatalogIds(): string[] {
+  const ids = new Set<string>();
+  for (const entry of Object.values(REGISTRY) as Array<{ models?: unknown[] }>) {
+    for (const model of entry?.models ?? []) {
+      const record = model as { id?: unknown; aliases?: unknown[] };
+      if (typeof record?.id === "string") ids.add(record.id);
+      for (const alias of record?.aliases ?? []) {
+        if (typeof alias === "string") ids.add(alias);
+      }
+    }
+  }
+  return [...ids];
+}
+
+/** A catalog id is retired when its bare form (after any `vendor/` prefix) is retired. */
+function isRetired(id: string): boolean {
+  const lower = id.toLowerCase();
+  if (retiredIds.has(lower)) return true;
+  const slash = lower.lastIndexOf("/");
+  return slash !== -1 && retiredIds.has(lower.slice(slash + 1));
+}
+
+describe("#11503 FITNESS_TABLE carries no retired or version-less rows", () => {
+  it("scores no routable retired model through the static table", () => {
+    // Scoped to ids the catalog can actually route: those are the ones layer 4 ranks.
+    // (Retired ids absent from the catalog — `gpt-4o-audio-preview` and friends — are
+    // unroutable, so a row matching them cannot invert a routing decision.)
+    const routableRetired = collectCatalogIds().filter(isRetired);
+    expect(routableRetired.length).toBeGreaterThan(0);
+
+    const scored = routableRetired
+      .flatMap((id) =>
+        TASK_TYPES.map((task) => ({ id, task, score: getStaticFitnessTableScore(id, task) }))
+      )
+      .filter((row) => row.score !== null);
+
+    expect(scored).toEqual([]);
+  });
+
+  it("does not capture live models through a version-less family row", () => {
+    // These are live flagships; before #11503 the family rows either scored them from a
+    // sibling's number or (worse) left them at 0.5 while a dead model scored 0.98.
+    expect(getStaticFitnessTableScore("claude-sonnet-5", "coding")).toBeNull();
+    expect(getStaticFitnessTableScore("claude-fable-5-thinking-max", "coding")).toBeNull();
+    expect(getStaticFitnessTableScore("gpt-5.6-sol-xhigh", "coding")).toBeNull();
+  });
+
+  it("matches patterns on segment boundaries only", () => {
+    // `solar-pro3` contains "o3" but is not an o3 model.
+    expect(getStaticFitnessTableScore("solar-pro3", "coding")).toBeNull();
+    // `chatgpt-4o-latest` contains "-4o-" but not `gpt-4o` at a boundary. OpenAI shut it
+    // down on 2026-02-17; it used to inherit the live flagship's 0.9.
+    expect(getStaticFitnessTableScore("chatgpt-4o-latest", "coding")).toBeNull();
+  });
+
+  it("keeps hyphen-suffixed and vendor-prefixed forms of a versioned row", () => {
+    expect(getStaticFitnessTableScore("gpt-4o-mini", "coding")).toBe(0.8);
+    expect(getStaticFitnessTableScore("gpt-4o-2024-11-20", "coding")).toBe(0.9);
+    expect(getStaticFitnessTableScore("o3-mini", "coding")).toBe(0.95);
+    expect(getStaticFitnessTableScore("openai/o3", "coding")).toBe(0.95);
+  });
+});
diff --git a/open-sse/services/autoCombo/__tests__/taskFitness-pattern-order-8603.test.ts b/open-sse/services/autoCombo/__tests__/taskFitness-pattern-order-8603.test.ts
index 643a15c123..509eff5acb 100644
--- a/open-sse/services/autoCombo/__tests__/taskFitness-pattern-order-8603.test.ts
+++ b/open-sse/services/autoCombo/__tests__/taskFitness-pattern-order-8603.test.ts
@@ -46,8 +46,11 @@ describe("#8603 static fitness table matches longest pattern first", () => {
   });
 
   it("falls back to the default table for an unknown task type", () => {
-    // "claude-sonnet" is absent from a nonexistent table but present in `default`.
-    expect(getStaticFitnessTableScore("claude-sonnet", "no-such-task")).toBe(0.85);
+    // "gpt-4o" is absent from a nonexistent table but present in `default`, where it
+    // scores 0.85 rather than the 0.9 it gets for `coding`.
+    // (#11503 swapped the probe from the version-less "claude-sonnet" row, which that
+    // PR removed from the table; the fallback behaviour under test is unchanged.)
+    expect(getStaticFitnessTableScore("gpt-4o", "no-such-task")).toBe(0.85);
   });
 
   it("returns null when nothing matches", () => {
diff --git a/open-sse/services/autoCombo/taskFitness.ts b/open-sse/services/autoCombo/taskFitness.ts
index 83899365e3..e67637fe3b 100644
--- a/open-sse/services/autoCombo/taskFitness.ts
+++ b/open-sse/services/autoCombo/taskFitness.ts
@@ -11,11 +11,26 @@
  *     from, when `resolveScoresAs` resolves one (#11489). Reported as
  *     `<source>:inherited`.
  * 3. Models.dev tier — derived from `model_capabilities` table capability data
- * 4. Static FITNESS_TABLE — existing hardcoded lookup (current behavior)
- * 5. Wildcard boosts — existing pattern matching boosts (current behavior)
+ * 4. Static FITNESS_TABLE — small hand-maintained table of VERSIONED model ids
+ * 5. Wildcard boosts — pattern matching boosts over a neutral 0.5 baseline
+ *
+ * Layer 4 is deliberately small and versioned (#11503). It used to carry
+ * version-less family patterns (`claude-sonnet`, `qwen`, `llama`, `codex`, …) that
+ * matched by substring, so it kept scoring model families whose members the vendors
+ * had already retired — and it scored them ABOVE live flagships it had never heard
+ * of. Recognition by the table, not availability, decided rank.
+ *
+ * Two rules keep it honest:
+ *  - Every row names a versioned id that exists in the provider catalog. A family
+ *    pattern that would silently adopt every future member of that family does not
+ *    belong here; `scripts/check/check-model-lifecycle.mjs` fails the build when a
+ *    row starts matching an id the vendor has retired.
+ *  - An id this table does not know falls through to the wildcard baseline of 0.5.
+ *    That 0.5 means "no evidence", NOT "mediocre model" — it is the neutral point,
+ *    and it must never be read as a quality claim about the model.
  */
 
-// ─── Static fitness table (unchanged, fallback layer 4) ─────────────────
+// ─── Static fitness table (versioned rows only, fallback layer 4) ────────
 
 import { getDbInstance } from "../../../src/lib/db/core.ts";
 import {
@@ -27,18 +42,11 @@ import { resolveScoresAs } from "./scoresAs.ts";
 
 const FITNESS_TABLE: Record<string, Record<string, number>> = {
   coding: {
-    "claude-sonnet": 0.95,
-    "claude-opus": 0.92,
-    "claude-haiku": 0.78,
     "gpt-4o": 0.9,
     "gpt-4o-mini": 0.8,
     "gpt-4-turbo": 0.88,
-    o1: 0.93,
     o3: 0.95,
     "o4-mini": 0.88,
-    codex: 0.98,
-    "gemini-pro": 0.85,
-    "gemini-flash": 0.8,
     "gemini-2.5-pro": 0.92,
     "gemini-2.5-flash": 0.82,
     "deepseek-coder": 0.9,
@@ -46,98 +54,54 @@ const FITNESS_TABLE: Record<string, Record<string, number>> = {
     "deepseek-r1": 0.88,
     "deepseek-chat": 0.84, // DeepSeek V3.2 Chat — strong code performance
     "deepseek-v3.2": 0.86, // Explicit V3.2 alias
-    qwen: 0.78,
-    llama: 0.72,
-    mistral: 0.75,
-    mixtral: 0.77,
-    // Grok-4 fast — good code, ultra-low latency (1143ms P50)
-    "grok-4-fast": 0.8,
-    "grok-4": 0.82,
     "grok-3": 0.8,
-    // Kimi K2.5 — agentic with tool calling, good at code tasks
-    "kimi-k2": 0.82,
-    // GLM-5.1 / GLM-5 — Z.AI reasoning models, 200K context / 128k output
+    // GLM-5.1 — Z.AI reasoning model, 200K context / 128k output
     "glm-5.1": 0.78,
-    "glm-5": 0.78,
     // MiniMax M2.5 — reasoning support helps complex code
     "minimax-m2.5": 0.75,
     "minimax-m2": 0.72,
   },
   review: {
-    "claude-sonnet": 0.92,
-    "claude-opus": 0.95,
-    "claude-haiku": 0.7,
     "gpt-4o": 0.88,
     "gpt-4o-mini": 0.72,
-    o1: 0.9,
     o3: 0.92,
-    "gemini-pro": 0.9,
     "gemini-2.5-pro": 0.93,
-    "gemini-flash": 0.75,
     "deepseek-r1": 0.85,
     "deepseek-v3": 0.8,
   },
   planning: {
-    "claude-opus": 0.95,
-    "claude-sonnet": 0.9,
     "gpt-4o": 0.88,
-    o1: 0.92,
     o3: 0.95,
     "gemini-2.5-pro": 0.93,
-    "gemini-pro": 0.88,
     "deepseek-r1": 0.85,
   },
   analysis: {
-    "claude-opus": 0.95,
-    "claude-sonnet": 0.92,
     "gemini-2.5-pro": 0.95,
-    "gemini-pro": 0.88,
     "gemini-3.1-pro": 0.95, // Gemini 3.1 Pro — 1M context, ideal for long analysis
     "gpt-4o": 0.85,
-    o1: 0.9,
     o3: 0.93,
     "deepseek-r1": 0.88,
     "deepseek-chat": 0.8,
-    "kimi-k2": 0.82, // Kimi K2.5 agentic — good for analysis
     "glm-5.1": 0.82, // GLM-5.1 free reasoning, 200K context for long analysis
-    "glm-5": 0.78, // GLM-5 with 128k output for long analysis
     "minimax-m2.5": 0.76,
   },
   debugging: {
-    "claude-sonnet": 0.93,
-    "claude-opus": 0.9,
     "gpt-4o": 0.88,
-    o1: 0.85,
     "deepseek-coder": 0.9,
     "deepseek-v3": 0.82,
-    "gemini-flash": 0.78,
-    codex: 0.92,
   },
   documentation: {
-    "claude-sonnet": 0.9,
-    "claude-opus": 0.88,
     "gpt-4o": 0.92,
     "gpt-4o-mini": 0.85,
-    "gemini-pro": 0.88,
-    "gemini-flash": 0.82,
     "deepseek-v3": 0.78,
   },
   default: {
-    "claude-sonnet": 0.85,
-    "claude-opus": 0.85,
     "gpt-4o": 0.85,
-    "gemini-pro": 0.8,
     "gemini-3.1-pro": 0.85,
     "deepseek-v3": 0.75,
     "deepseek-chat": 0.74,
-    "gemini-flash": 0.72,
-    // New models from ClawRouter analysis (2026-03-17):
-    "grok-4-fast": 0.72, // ultra-fast, suitable for all tasks
-    "grok-4": 0.74,
     "grok-3": 0.73,
-    "kimi-k2": 0.76, // agentic multi-step tasks
     "glm-5.1": 0.75,
-    "glm-5": 0.7,
     "minimax-m2.5": 0.7,
   },
 };
@@ -301,6 +265,36 @@ export function getModelsDevTierFitness(model: string, taskType: string): number
 
 // ─── Resolution chain ───────────────────────────────────────────────────
 
+/** Characters that separate the segments of a model id (`openai/gpt-4o-2024-05-13`). */
+const SEGMENT_SEPARATORS = new Set(["-", ".", "/"]);
+
+/**
+ * True when `pattern` occurs in `model` delimited by segment boundaries on BOTH sides —
+ * i.e. it starts at the beginning of the id or right after a `-` / `.` / `/`, and ends at
+ * the end of the id or right before one.
+ *
+ * This is what makes a versioned row safe to keep (#11503). Substring matching scored
+ * models the row was never about:
+ *   - `o3` matched `solar-pro3` (an unrelated Upstage model)
+ *   - `gpt-4o` matched `chatgpt-4o-latest`, which OpenAI shut down on 2026-02-17 —
+ *     so a dead model inherited the live flagship's 0.9. With boundary matching the
+ *     `-4o-` inside `chatgpt-4o-latest` is not a `gpt-4o` occurrence at a boundary
+ *     (the preceding character is `t`), so it falls through to the neutral 0.5.
+ * Legitimate forms still match: `o3`, `o3-mini`, `openai/o3`, `gpt-4o-2024-05-13`.
+ */
+function matchesAtSegmentBoundary(model: string, pattern: string): boolean {
+  if (!pattern) return false;
+  let index = model.indexOf(pattern);
+  while (index !== -1) {
+    const startsAtBoundary = index === 0 || SEGMENT_SEPARATORS.has(model[index - 1]);
+    const endIndex = index + pattern.length;
+    const endsAtBoundary = endIndex === model.length || SEGMENT_SEPARATORS.has(model[endIndex]);
+    if (startsAtBoundary && endsAtBoundary) return true;
+    index = model.indexOf(pattern, index + 1);
+  }
+  return false;
+}
+
 /**
  * Resolve a model id against the static fitness table, LONGEST PATTERN FIRST (#8603).
  *
@@ -315,6 +309,11 @@ export function getModelsDevTierFitness(model: string, taskType: string): number
  * DB (user_override / arena_elo / models.dev tier) before reaching layer 4, so pinning
  * the ordering guarantee through `getTaskFitness` would depend on DB fixture state.
  * `taskFitness-pattern-order-8603.test.ts` calls this directly instead.
+ *
+ * Matching is anchored to SEGMENT BOUNDARIES since #11503: a plain `String.includes`
+ * let a row leak into ids that merely contain its characters — `o3` scored
+ * `solar-pro3`, and `gpt-4o` scored `chatgpt-4o-latest` (a different, retired model).
+ * See `matchesAtSegmentBoundary`.
  */
 export function getStaticFitnessTableScore(model: string, taskType: string): number | null {
   const normalizedModel = model.toLowerCase();
@@ -322,7 +321,7 @@ export function getStaticFitnessTableScore(model: string, taskType: string): num
   const table = FITNESS_TABLE[normalizedTask] || FITNESS_TABLE.default;
   const sortedEntries = Object.entries(table).sort((a, b) => b[0].length - a[0].length);
   for (const [pattern, score] of sortedEntries) {
-    if (normalizedModel.includes(pattern)) return score;
+    if (matchesAtSegmentBoundary(normalizedModel, pattern)) return score;
   }
   return null;
 }
diff --git a/open-sse/services/model.ts b/open-sse/services/model.ts
index 04be2c9f35..2c28b60953 100644
--- a/open-sse/services/model.ts
+++ b/open-sse/services/model.ts
@@ -276,7 +276,16 @@ function resolveProviderModelAlias(
   return aliases?.[modelId] || modelId;
 }
 
-function hasKnownProviderModel(providerOrAlias: string | null | undefined, modelId: string | null) {
+/**
+ * True when the provider serves `modelId` under that exact id (static model list or
+ * a provider-specific alias). Exported for the deprecation-alias provider guard
+ * (#11503): a globally deprecated id that this provider still serves must not be
+ * rewritten out from under the request.
+ */
+export function hasKnownProviderModel(
+  providerOrAlias: string | null | undefined,
+  modelId: string | null
+) {
   if (!providerOrAlias || !modelId) return false;
 
   const providerId = resolveProviderAlias(providerOrAlias);
diff --git a/open-sse/services/modelDeprecation.ts b/open-sse/services/modelDeprecation.ts
index 90ac077b1d..8a120d6de0 100644
--- a/open-sse/services/modelDeprecation.ts
+++ b/open-sse/services/modelDeprecation.ts
@@ -7,6 +7,8 @@
  * Supports both built-in aliases (static) and custom aliases (persisted via Settings API).
  */
 
+import { hasKnownProviderModel } from "./model.ts";
+
 // ── Built-in Deprecation Aliases ────────────────────────────────────────────
 // These are known renames/retirements across providers.
 // Format: deprecated ID → current ID
@@ -20,17 +22,23 @@ const BUILT_IN_ALIASES: Record<string, string> = {
   "gemini-2.0-flash": "gemini-2.5-flash",
   "gemini-2.0-flash-lite": "gemini-3.1-flash-lite",
   "gemini-3.1-flash-lite-preview": "gemini-3.1-flash-lite",
-  "gemini-3-pro-high": "gemini-3.1-pro-high",
+  // #11503: the catalog spells this one with hyphens ("gemini-3-1-pro-high"); the
+  // dotted form is not a routable id, so the rewrite used to guarantee a 404.
+  "gemini-3-pro-high": "gemini-3-1-pro-high",
   "gemini-3-pro-low": "gemini-3.1-pro-low",
   // Retired free Gemma (was in the gemini-free pool) → current gemini-free model
   "gemma-4": "gemini-3.1-flash-lite",
 
-  // Claude legacy → current
-  "claude-3-opus-20240229": "claude-opus-4-20250514",
-  "claude-3-sonnet-20240229": "claude-sonnet-4-20250514",
-  "claude-3-haiku-20240307": "claude-3-5-sonnet-20241022",
-  "claude-3-5-sonnet-latest": "claude-sonnet-4-20250514",
-  "claude-3-5-haiku-latest": "claude-3-5-sonnet-20241022",
+  // Claude legacy → current.
+  // #11503: these five forwarded one retired id to another (claude-opus-4-20250514 and
+  // claude-sonnet-4-20250514 retired 2026-06-15, claude-3-5-sonnet-20241022 retired
+  // 2025-10-28), so every rewrite landed on a model the vendor no longer serves. The
+  // targets below are the replacements Anthropic publishes on its deprecations page.
+  "claude-3-opus-20240229": "claude-opus-4-8",
+  "claude-3-sonnet-20240229": "claude-sonnet-4-6",
+  "claude-3-haiku-20240307": "claude-haiku-4-5-20251001",
+  "claude-3-5-sonnet-latest": "claude-sonnet-4-6",
+  "claude-3-5-haiku-latest": "claude-haiku-4-5-20251001",
 
   // Kimi/Moonshot — Fireworks long-path aliases (#265)
   "accounts/fireworks/models/kimi-k2p5": "moonshotai/Kimi-K2.5",
@@ -57,7 +65,9 @@ const BUILT_IN_ALIASES: Record<string, string> = {
   // Llama short aliases
   "llama-3.3": "llama-3.3-70b-versatile",
   "llama-3-70b": "llama-3.3-70b-versatile",
-  "llama-3-8b": "llama3-8b-8192",
+  // #11503: llama3-8b-8192 was deprecated by Groq on 2025-08-30 and is not in the
+  // catalog; llama-3.1-8b-instant is the replacement Groq names.
+  "llama-3-8b": "llama-3.1-8b-instant",
 };
 
 // ── Custom Aliases (persisted via Settings API) ─────────────────────────────
@@ -106,20 +116,30 @@ export function getAllAliases(): Record<string, string> {
  * Resolve a model alias to its current ID.
  * Custom aliases override built-in ones.
  *
+ * The table is GLOBAL but the catalog is not: `kimi-k2`, `gemini-2.0-flash` and friends
+ * are still served under their original id by some aggregators, and rewriting them there
+ * turns a working request into a 404. So when the caller knows which provider will serve
+ * the request (#11503), a provider that lists the id as-is wins over the alias table.
+ * Callers with no provider in hand keep the previous unconditional behaviour.
+ *
  * @param {string} modelId - The model ID to resolve
+ * @param {string | null} [provider] - Provider (id or alias) that will serve the request
  * @returns {string} The resolved model ID, or the original if not deprecated
  */
-export function resolveModelAlias(modelId: string): string {
+export function resolveModelAlias(modelId: string, provider?: string | null): string {
   if (!modelId) return modelId;
 
-  // Check custom aliases first (higher priority)
+  // Check custom aliases first (higher priority). An operator-authored alias is an
+  // explicit instruction, so it applies even when the provider serves the source id.
   const custom = customAliases();
   if (custom[modelId]) return custom[modelId];
 
-  // Then check built-in
-  if (BUILT_IN_ALIASES[modelId]) return BUILT_IN_ALIASES[modelId];
+  if (!BUILT_IN_ALIASES[modelId]) return modelId;
 
-  return modelId;
+  // The provider serves this id itself — nothing is deprecated from its point of view.
+  if (provider && hasKnownProviderModel(provider, modelId)) return modelId;
+
+  return BUILT_IN_ALIASES[modelId];
 }
 
 /**
diff --git a/package.json b/package.json
index f0957e7ac5..4715e5ed37 100644
--- a/package.json
+++ b/package.json
@@ -162,6 +162,7 @@
     "check:cli-i18n": "node scripts/check/check-cli-i18n.mjs",
     "check:openapi-coverage": "node scripts/check/check-openapi-coverage.mjs",
     "check:openapi-security-tiers": "node scripts/check/check-openapi-security-tiers.mjs",
+    "check:model-lifecycle": "node --import tsx/esm scripts/check/check-model-lifecycle.mjs",
     "check:provider-consistency": "bun scripts/check/check-provider-consistency.ts",
     "check:provider-assets": "node scripts/check/check-provider-assets.mjs",
     "check:nvidia-catalog-drift": "node --import tsx/esm scripts/check/check-nvidia-catalog-drift.ts",
@@ -210,6 +211,7 @@
     "check:workflows": "node scripts/check/check-workflows.mjs",
     "quality:collect": "node scripts/quality/collect-metrics.mjs",
     "quality:ratchet": "node scripts/quality/check-quality-ratchet.mjs",
+    "quality:refresh-model-lifecycle": "node scripts/quality/refresh-model-lifecycle.mjs",
     "quality:gate": "npm run quality:collect && npm run quality:ratchet -- --allow-missing",
     "quality:scan": "node scripts/quality/run-all-gates.mjs",
     "quality:scan:fast": "node scripts/quality/run-all-gates.mjs --fast",
diff --git a/scripts/check/check-model-lifecycle.mjs b/scripts/check/check-model-lifecycle.mjs
new file mode 100644
index 0000000000..7bad03ec60
--- /dev/null
+++ b/scripts/check/check-model-lifecycle.mjs
@@ -0,0 +1,165 @@
+#!/usr/bin/env node
+// scripts/check/check-model-lifecycle.mjs
+// Gate anti-drift (#11503): as duas tabelas mantidas à mão que decidem roteamento —
+// FITNESS_TABLE (open-sse/services/autoCombo/taskFitness.ts, camada 4 do task fitness) e
+// BUILT_IN_ALIASES (open-sse/services/modelDeprecation.ts, reescreve `body.model` em toda
+// request) — apodrecem em silêncio quando o fornecedor aposenta um modelo. Em
+// release/v3.8.51 o resultado foi uma inversão de ranking (modelo morto 0.98 vs flagship
+// vivo 0.50) e aliases que garantiam 404. Este gate compara as duas contra o snapshot de
+// ciclo de vida em config/quality/model-lifecycle.json (sem rede; regenerar com
+// `npm run quality:refresh-model-lifecycle`).
+//
+// Três checagens, todas somadas antes do exit — nenhuma aborta as outras:
+//   (a) nenhum padrão do FITNESS_TABLE pontua um id aposentado que o catálogo roteia;
+//   (b) nenhum alvo de BUILT_IN_ALIASES está aposentado ou ausente do catálogo;
+//   (c) todo id aposentado ainda presente no REGISTRY tem encaminhamento em
+//       BUILT_IN_ALIASES ou consta em `allowedRetiredInCatalog` (a catraca a queimar).
+//
+// (a) é deliberadamente restrita aos ids ROTEÁVEIS: linhas versionadas legítimas como
+// `gpt-4o` também casam com ids aposentados que o catálogo nunca serviu
+// (`gpt-4o-audio-preview`), e esses não podem inverter decisão de roteamento nenhuma.
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { pathToFileURL } from "node:url";
+
+const ROOT = process.cwd();
+const SNAPSHOT_PATH = path.join(ROOT, "config/quality/model-lifecycle.json");
+const TASK_TYPES = ["coding", "review", "planning", "analysis", "debugging", "documentation"];
+
+/** Ids de modelo que o catálogo consegue rotear (id + aliases de cada modelo). */
+export function collectCatalogIds(registry) {
+  const ids = new Set();
+  for (const entry of Object.values(registry ?? {})) {
+    for (const model of entry?.models ?? []) {
+      if (typeof model?.id === "string") ids.add(model.id);
+      for (const alias of model?.aliases ?? []) {
+        if (typeof alias === "string") ids.add(alias);
+      }
+    }
+  }
+  return [...ids];
+}
+
+/** Um id do catálogo está aposentado quando sua forma nua (sem prefixo `vendor/`) está. */
+export function isRetiredId(id, retiredIds) {
+  const lower = String(id).toLowerCase();
+  if (retiredIds.has(lower)) return true;
+  const slash = lower.lastIndexOf("/");
+  return slash !== -1 && retiredIds.has(lower.slice(slash + 1));
+}
+
+/** (a) Linhas do FITNESS_TABLE que ainda pontuam um modelo aposentado e roteável. */
+export function findRetiredFitnessRows(routableRetiredIds, scoreFor, taskTypes = TASK_TYPES) {
+  const violations = [];
+  for (const id of routableRetiredIds) {
+    for (const task of taskTypes) {
+      const score = scoreFor(id, task);
+      if (score !== null && score !== undefined) {
+        violations.push(
+          `${id} scores ${score} for "${task}" via FITNESS_TABLE (vendor retired it)`
+        );
+      }
+    }
+  }
+  return violations;
+}
+
+/** (b) Alvos de alias aposentados ou fora do catálogo. */
+export function findBadAliasTargets(aliases, catalogIds, retiredIds) {
+  const catalog = new Set([...catalogIds].map((id) => id.toLowerCase()));
+  const violations = [];
+  for (const [source, target] of Object.entries(aliases)) {
+    const lower = String(target).toLowerCase();
+    if (!catalog.has(lower)) {
+      violations.push(`${source} → ${target} (no provider in REGISTRY serves this id)`);
+    } else if (retiredIds.has(lower)) {
+      violations.push(`${source} → ${target} (the vendor has retired this id)`);
+    }
+  }
+  return violations;
+}
+
+/** (c) Ids aposentados que o catálogo ainda roteia sem encaminhamento nem allowlist. */
+export function findUnforwardedRetiredIds(routableRetiredIds, aliases, allowlist) {
+  const allowed = new Set((allowlist ?? []).map((id) => String(id).toLowerCase()));
+  return routableRetiredIds
+    .filter((id) => !(id in aliases) && !allowed.has(String(id).toLowerCase()))
+    .map((id) => `${id} is retired but still routable with no BUILT_IN_ALIASES forward`);
+}
+
+export function readSnapshot(snapshotPath = SNAPSHOT_PATH) {
+  const snapshot = JSON.parse(fs.readFileSync(snapshotPath, "utf8"));
+  const retiredIds = new Set(
+    Object.entries(snapshot.retired ?? {})
+      .filter(([, entry]) => entry?.status === "retired")
+      .map(([id]) => id.toLowerCase())
+  );
+  return { snapshot, retiredIds };
+}
+
+async function loadProductionTables() {
+  // Nenhum gate pode migrar o banco do operador: taskFitness.ts importa src/lib/db/core.ts,
+  // então DATA_DIR aponta para um diretório descartável ANTES do import dinâmico.
+  process.env.DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-lifecycle-gate-"));
+  const [{ REGISTRY }, { getStaticFitnessTableScore }, { getBuiltInAliases }] = await Promise.all([
+    import(pathToFileURL(path.join(ROOT, "open-sse/config/providers/index.ts")).href),
+    import(pathToFileURL(path.join(ROOT, "open-sse/services/autoCombo/taskFitness.ts")).href),
+    import(pathToFileURL(path.join(ROOT, "open-sse/services/modelDeprecation.ts")).href),
+  ]);
+  return { REGISTRY, getStaticFitnessTableScore, getBuiltInAliases };
+}
+
+function report(label, violations, hint) {
+  if (!violations.length) {
+    console.log(`[model-lifecycle] OK — ${label}`);
+    return 0;
+  }
+  console.error(
+    `[model-lifecycle] ${violations.length} violation(s) — ${label}:\n` +
+      violations.map((v) => "  ✗ " + v).join("\n") +
+      `\n  → ${hint}`
+  );
+  return violations.length;
+}
+
+async function main() {
+  const { snapshot, retiredIds } = readSnapshot();
+  const { REGISTRY, getStaticFitnessTableScore, getBuiltInAliases } = await loadProductionTables();
+
+  const catalogIds = collectCatalogIds(REGISTRY);
+  const routableRetired = catalogIds.filter((id) => isRetiredId(id, retiredIds)).sort();
+  const aliases = getBuiltInAliases();
+
+  let failures = 0;
+  failures += report(
+    `FITNESS_TABLE scores none of the ${routableRetired.length} routable retired id(s)`,
+    findRetiredFitnessRows(routableRetired, getStaticFitnessTableScore),
+    "drop the row from FITNESS_TABLE in open-sse/services/autoCombo/taskFitness.ts, or replace it with the versioned id of the live successor."
+  );
+  failures += report(
+    `all ${Object.keys(aliases).length} BUILT_IN_ALIASES targets are live catalog models`,
+    findBadAliasTargets(aliases, catalogIds, retiredIds),
+    "point the alias at the replacement the vendor publishes (see `sources` in config/quality/model-lifecycle.json). Never invent a target."
+  );
+  failures += report(
+    "every routable retired id is forwarded or allowlisted",
+    findUnforwardedRetiredIds(routableRetired, aliases, snapshot.allowedRetiredInCatalog),
+    "add a BUILT_IN_ALIASES forward to the vendor's replacement, remove the model from the provider catalog, or (last resort) add the id to `allowedRetiredInCatalog` in config/quality/model-lifecycle.json with a tracking issue."
+  );
+
+  if (failures) {
+    console.error(`[model-lifecycle] FAIL — ${failures} violation(s) across 3 check(s).`);
+    process.exit(1);
+  }
+  console.log(
+    `[model-lifecycle] PASS — snapshot ${snapshot.generatedAt}, ${retiredIds.size} retired id(s), ${catalogIds.length} catalog id(s).`
+  );
+}
+
+if (import.meta.url === pathToFileURL(process.argv[1] || "").href) {
+  main().catch((err) => {
+    console.error(`[model-lifecycle] ERROR — ${err?.message ?? err}`);
+    process.exit(1);
+  });
+}
diff --git a/scripts/quality/refresh-model-lifecycle.mjs b/scripts/quality/refresh-model-lifecycle.mjs
new file mode 100644
index 0000000000..151821632b
--- /dev/null
+++ b/scripts/quality/refresh-model-lifecycle.mjs
@@ -0,0 +1,200 @@
+#!/usr/bin/env node
+// scripts/quality/refresh-model-lifecycle.mjs
+// Regenera config/quality/model-lifecycle.json a partir das páginas de depreciação de
+// primeira mão listadas em `sources`. NÃO roda em CI (o gate check:model-lifecycle é
+// offline, por design): é uma ferramenta de manutenção, executada à mão quando um
+// fornecedor publica uma nova rodada de aposentadorias.
+//
+// Regra dura: o script NUNCA descarta uma entrada em silêncio. Fornecedor cuja página
+// não pôde ser parseada mantém as entradas atuais do snapshot e imprime
+// "manual review needed" — assim uma mudança de layout upstream vira um aviso, não uma
+// perda de dados que abriria o gate.
+//
+// Uso:
+//   npm run quality:refresh-model-lifecycle            # escreve o snapshot
+//   npm run quality:refresh-model-lifecycle -- --dry-run
+import fs from "node:fs";
+import path from "node:path";
+import { pathToFileURL } from "node:url";
+
+const ROOT = process.cwd();
+const SNAPSHOT_PATH = path.join(ROOT, "config/quality/model-lifecycle.json");
+const DRY_RUN = process.argv.includes("--dry-run");
+
+/** Fornecedor de cada source, na ordem em que aparecem no snapshot. */
+const VENDOR_BY_HOST = {
+  "platform.claude.com": "anthropic",
+  "developers.openai.com": "openai",
+  "ai.google.dev": "google",
+  "docs.x.ai": "xai",
+  "console.groq.com": "groq",
+};
+
+/**
+ * Parser da página da Anthropic: uma tabela markdown
+ * `| API model name | Current state | Deprecated | Tentative retirement date |`.
+ * Só linhas cujo estado contém "retired"/"deprecated" viram entradas.
+ *
+ * @returns {Record<string, {vendor: string, status: string, retiredOn: string|null, replacement: string|null}>}
+ */
+export function parseAnthropicTable(text) {
+  const out = {};
+  const rows = text.split("\n").filter((line) => line.trim().startsWith("|"));
+  for (const row of rows) {
+    const cells = row
+      .split("|")
+      .slice(1, -1)
+      .map((cell) => cell.trim());
+    if (cells.length < 3) continue;
+    const [model, state, deprecatedOn, retirementDate] = cells;
+    if (!/^[a-z0-9][a-z0-9.\-]*$/i.test(model)) continue; // pula cabeçalho e separadores
+    const lowerState = String(state).toLowerCase();
+    const status = lowerState.includes("retired")
+      ? "retired"
+      : lowerState.includes("deprecated")
+        ? "retiring"
+        : null;
+    if (!status) continue;
+    out[model] = {
+      vendor: "anthropic",
+      status,
+      retiredOn: normalizeDate(retirementDate) ?? normalizeDate(deprecatedOn),
+      // A página lista o substituto em prosa, fora da tabela. Preencher aqui inventaria
+      // dado: o valor vigente do snapshot é preservado pelo merge.
+      replacement: null,
+    };
+  }
+  return out;
+}
+
+/** "2026-06-15" ou "June 15, 2026" → "2026-06-15"; qualquer outra coisa → null. */
+export function normalizeDate(value) {
+  if (!value) return null;
+  const iso = String(value).match(/\d{4}-\d{2}-\d{2}/);
+  if (iso) return iso[0];
+  const parsed = Date.parse(String(value));
+  return Number.isNaN(parsed) ? null : new Date(parsed).toISOString().slice(0, 10);
+}
+
+/**
+ * Funde entradas recém-parseadas sobre as atuais SEM perder nada:
+ * - entrada nova → adicionada;
+ * - entrada existente → status/retiredOn atualizados, `replacement` preservado quando o
+ *   parser não trouxe um (o fornecedor nem sempre publica substituto);
+ * - entrada que sumiu do parse → mantida (uma página pode paginar ou mudar de layout).
+ *
+ * @returns {{merged: Object, added: string[], updated: string[], kept: string[]}}
+ */
+export function mergeVendorEntries(current, parsed, vendor) {
+  const merged = { ...current };
+  const added = [];
+  const updated = [];
+  const kept = [];
+
+  for (const [id, entry] of Object.entries(parsed)) {
+    const existing = current[id];
+    if (!existing) {
+      merged[id] = entry;
+      added.push(id);
+      continue;
+    }
+    const next = {
+      ...existing,
+      status: entry.status,
+      retiredOn: entry.retiredOn ?? existing.retiredOn,
+      replacement: entry.replacement ?? existing.replacement,
+    };
+    merged[id] = next;
+    if (JSON.stringify(next) !== JSON.stringify(existing)) updated.push(id);
+  }
+
+  for (const [id, entry] of Object.entries(current)) {
+    if (entry?.vendor === vendor && !(id in parsed)) kept.push(id);
+  }
+  return { merged, added, updated, kept };
+}
+
+async function fetchText(url) {
+  const res = await fetch(url, { headers: { "user-agent": "omniroute-lifecycle-refresh" } });
+  if (!res.ok) throw new Error(`HTTP ${res.status}`);
+  return res.text();
+}
+
+async function main() {
+  const snapshot = JSON.parse(fs.readFileSync(SNAPSHOT_PATH, "utf8"));
+  let retired = { ...snapshot.retired };
+  const warnings = [];
+
+  for (const url of snapshot.sources) {
+    const host = new URL(url).host;
+    const vendor = VENDOR_BY_HOST[host] ?? host;
+    let text;
+    try {
+      text = await fetchText(url);
+    } catch (err) {
+      warnings.push(
+        `${vendor}: fetch failed (${err.message}) — existing entries kept, manual review needed`
+      );
+      continue;
+    }
+
+    if (vendor !== "anthropic") {
+      // Só a Anthropic publica a lista como tabela estável. Os demais são HTML/JS que
+      // mudam de forma; parsear por heurística arriscaria apagar dados corretos.
+      warnings.push(
+        `${vendor}: no reliable parser — existing entries kept, manual review needed (${url})`
+      );
+      continue;
+    }
+
+    const parsed = parseAnthropicTable(text);
+    if (!Object.keys(parsed).length) {
+      warnings.push(
+        `${vendor}: table parsed to 0 rows (layout change?) — existing entries kept, manual review needed`
+      );
+      continue;
+    }
+    const { merged, added, updated, kept } = mergeVendorEntries(retired, parsed, vendor);
+    retired = merged;
+    console.log(
+      `[refresh-model-lifecycle] ${vendor}: ${added.length} added, ${updated.length} updated, ${kept.length} kept (not in this parse)`
+    );
+    for (const id of added) console.log(`  + ${id}`);
+    for (const id of updated) console.log(`  ~ ${id}`);
+  }
+
+  const next = {
+    ...snapshot,
+    generatedAt: new Date().toISOString().slice(0, 10),
+    retired,
+  };
+
+  for (const warning of warnings) console.warn(`[refresh-model-lifecycle] WARN ${warning}`);
+
+  const before = Object.keys(snapshot.retired).length;
+  const after = Object.keys(retired).length;
+  if (after < before) {
+    console.error(
+      `[refresh-model-lifecycle] ABORT — entry count dropped ${before} → ${after}. The script must never lose an entry; investigate before writing.`
+    );
+    process.exit(1);
+  }
+
+  if (DRY_RUN) {
+    console.log(
+      `[refresh-model-lifecycle] dry run — ${before} → ${after} entries, nothing written.`
+    );
+    return;
+  }
+  fs.writeFileSync(SNAPSHOT_PATH, JSON.stringify(next, null, 2) + "\n");
+  console.log(
+    `[refresh-model-lifecycle] wrote ${path.relative(ROOT, SNAPSHOT_PATH)} — ${after} entries. Review the diff, then run \`npm run check:model-lifecycle\`.`
+  );
+}
+
+if (import.meta.url === pathToFileURL(process.argv[1] || "").href) {
+  main().catch((err) => {
+    console.error(`[refresh-model-lifecycle] ERROR — ${err?.message ?? err}`);
+    process.exit(1);
+  });
+}
diff --git a/tests/unit/check-model-lifecycle-gate.test.ts b/tests/unit/check-model-lifecycle-gate.test.ts
new file mode 100644
index 0000000000..d717ffabe4
--- /dev/null
+++ b/tests/unit/check-model-lifecycle-gate.test.ts
@@ -0,0 +1,95 @@
+/**
+ * Unit coverage for the #11503 drift gate (`scripts/check/check-model-lifecycle.mjs`).
+ *
+ * The gate's value is that it goes red when a hand-maintained routing table starts
+ * pointing at a model the vendor retired, so each of its three checks is exercised here
+ * against small fixtures rather than against the live catalog (which would make the test
+ * a duplicate of the gate run itself, and red for reasons unrelated to the logic).
+ */
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+import {
+  collectCatalogIds,
+  isRetiredId,
+  findRetiredFitnessRows,
+  findBadAliasTargets,
+  findUnforwardedRetiredIds,
+} from "../../scripts/check/check-model-lifecycle.mjs";
+
+const RETIRED = new Set(["dead-model-1", "dead-model-2", "gpt-5.2-codex"]);
+
+describe("check-model-lifecycle: catalog extraction", () => {
+  it("collects model ids and their aliases", () => {
+    const registry = {
+      alpha: { models: [{ id: "live-1", aliases: ["live-1-alias"] }, { id: "dead-model-1" }] },
+      beta: { models: [{ id: "live-2" }] },
+      gamma: {},
+    };
+    assert.deepEqual(collectCatalogIds(registry).sort(), [
+      "dead-model-1",
+      "live-1",
+      "live-1-alias",
+      "live-2",
+    ]);
+  });
+
+  it("treats a vendor-prefixed id as retired when its bare form is", () => {
+    assert.equal(isRetiredId("openai/gpt-5.2-codex", RETIRED), true);
+    assert.equal(isRetiredId("GPT-5.2-Codex", RETIRED), true);
+    assert.equal(isRetiredId("live-1", RETIRED), false);
+  });
+});
+
+describe("check-model-lifecycle: (a) retired ids scored by FITNESS_TABLE", () => {
+  const scoreFor = (id: string, task: string) =>
+    id === "dead-model-1" && task === "coding" ? 0.98 : null;
+
+  it("flags a retired id the table still scores", () => {
+    const violations = findRetiredFitnessRows(["dead-model-1"], scoreFor, ["coding", "review"]);
+    assert.equal(violations.length, 1);
+    assert.match(violations[0], /dead-model-1 scores 0\.98 for "coding"/);
+  });
+
+  it("passes when no retired id resolves through the table", () => {
+    assert.deepEqual(findRetiredFitnessRows(["dead-model-2"], scoreFor, ["coding"]), []);
+  });
+});
+
+describe("check-model-lifecycle: (b) alias targets", () => {
+  const catalog = ["live-1", "dead-model-1"];
+
+  it("flags a target absent from the catalog", () => {
+    const violations = findBadAliasTargets({ old: "not-in-catalog" }, catalog, RETIRED);
+    assert.equal(violations.length, 1);
+    assert.match(violations[0], /no provider in REGISTRY serves this id/);
+  });
+
+  it("flags a target the vendor has retired", () => {
+    const violations = findBadAliasTargets({ old: "dead-model-1" }, catalog, RETIRED);
+    assert.equal(violations.length, 1);
+    assert.match(violations[0], /the vendor has retired this id/);
+  });
+
+  it("passes for a live catalog target", () => {
+    assert.deepEqual(findBadAliasTargets({ old: "live-1" }, catalog, RETIRED), []);
+  });
+});
+
+describe("check-model-lifecycle: (c) routable retired ids", () => {
+  it("flags a retired id with neither forward nor allowlist entry", () => {
+    const violations = findUnforwardedRetiredIds(["dead-model-1"], {}, []);
+    assert.equal(violations.length, 1);
+    assert.match(violations[0], /retired but still routable/);
+  });
+
+  it("accepts an allowlisted id", () => {
+    assert.deepEqual(findUnforwardedRetiredIds(["dead-model-1"], {}, ["dead-model-1"]), []);
+  });
+
+  it("accepts an id that has a BUILT_IN_ALIASES forward", () => {
+    assert.deepEqual(
+      findUnforwardedRetiredIds(["dead-model-1"], { "dead-model-1": "live-1" }, []),
+      []
+    );
+  });
+});
diff --git a/tests/unit/model-deprecation-aliases-11503.test.ts b/tests/unit/model-deprecation-aliases-11503.test.ts
new file mode 100644
index 0000000000..5d841225eb
--- /dev/null
+++ b/tests/unit/model-deprecation-aliases-11503.test.ts
@@ -0,0 +1,104 @@
+/**
+ * TDD regression for #11503: `BUILT_IN_ALIASES` is applied to `body.model` on every
+ * request (`modelLifecyclePolicy.ts`), so a stale target is a guaranteed 404. Seven rows
+ * forwarded to a model the vendor had retired or the catalog never carried — five Claude
+ * rows chained one retired id to another, `gemini-3-pro-high` used a spelling
+ * (`gemini-3.1-pro-high`) no provider serves, and `llama-3-8b` pointed at a Groq model
+ * deprecated on 2025-08-30.
+ *
+ * The table is also global while the catalog is not: aggregators still serve `kimi-k2`
+ * and `gemini-2.0-flash` under their original ids, and the unconditional rewrite broke
+ * them. `resolveModelAlias` now takes the provider and skips the rewrite when that
+ * provider serves the id as-is.
+ */
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import {
+  getBuiltInAliases,
+  resolveModelAlias,
+  setCustomAliases,
+} from "../../open-sse/services/modelDeprecation.ts";
+import { REGISTRY } from "../../open-sse/config/providers/index.ts";
+
+const lifecycle = JSON.parse(
+  readFileSync(
+    fileURLToPath(new URL("../../config/quality/model-lifecycle.json", import.meta.url)),
+    "utf8"
+  )
+) as { retired: Record<string, { status: string }> };
+
+const retiredIds = new Set(
+  Object.entries(lifecycle.retired)
+    .filter(([, entry]) => entry.status === "retired")
+    .map(([id]) => id.toLowerCase())
+);
+
+/** Every model id the catalog can route, lowercased, including per-model aliases. */
+const catalogIds = (() => {
+  const ids = new Set<string>();
+  for (const entry of Object.values(REGISTRY) as Array<{ models?: unknown[] }>) {
+    for (const model of entry?.models ?? []) {
+      const record = model as { id?: unknown; aliases?: unknown[] };
+      if (typeof record?.id === "string") ids.add(record.id.toLowerCase());
+      for (const alias of record?.aliases ?? []) {
+        if (typeof alias === "string") ids.add(alias.toLowerCase());
+      }
+    }
+  }
+  return ids;
+})();
+
+describe("#11503 BUILT_IN_ALIASES point at live catalog models", () => {
+  const aliases = Object.entries(getBuiltInAliases());
+
+  it("has aliases to check", () => {
+    assert.ok(aliases.length > 0);
+  });
+
+  for (const [source, target] of aliases) {
+    it(`forwards ${source} to a model the catalog serves`, () => {
+      assert.ok(
+        catalogIds.has(target.toLowerCase()),
+        `"${source}" forwards to "${target}", which no provider in REGISTRY serves`
+      );
+    });
+
+    it(`forwards ${source} to a model the vendor has not retired`, () => {
+      assert.ok(
+        !retiredIds.has(target.toLowerCase()),
+        `"${source}" forwards to "${target}", which the vendor has retired`
+      );
+    });
+  }
+
+  it("applies the corrected Claude replacement", () => {
+    // Was claude-opus-4-20250514, retired 2026-06-15.
+    assert.equal(resolveModelAlias("claude-3-opus-20240229"), "claude-opus-4-8");
+  });
+});
+
+describe("#11503 resolveModelAlias respects the serving provider", () => {
+  it("leaves the id alone when the provider serves it as-is", () => {
+    assert.equal(resolveModelAlias("kimi-k2", "t3-web"), "kimi-k2");
+  });
+
+  it("still rewrites for a provider that only knows the canonical id", () => {
+    assert.equal(resolveModelAlias("kimi-k2", "fireworks"), "moonshotai/Kimi-K2");
+  });
+
+  it("keeps the unconditional rewrite when no provider is known", () => {
+    assert.equal(resolveModelAlias("kimi-k2"), "moonshotai/Kimi-K2");
+  });
+
+  it("lets a custom alias win over a built-in one, provider or not", () => {
+    setCustomAliases({ "kimi-k2": "custom-target" });
+    try {
+      assert.equal(resolveModelAlias("kimi-k2"), "custom-target");
+      assert.equal(resolveModelAlias("kimi-k2", "t3-web"), "custom-target");
+    } finally {
+      setCustomAliases({});
+    }
+  });
+});
diff --git a/tests/unit/model-deprecation.test.ts b/tests/unit/model-deprecation.test.ts
index 7560a6afc2..42c7cc4e46 100644
--- a/tests/unit/model-deprecation.test.ts
+++ b/tests/unit/model-deprecation.test.ts
@@ -33,8 +33,10 @@ test("resolveModelAlias: resolves deprecated Gemini model", () => {
 });
 
 test("resolveModelAlias: resolves deprecated Claude model", () => {
-  assert.equal(resolveModelAlias("claude-3-opus-20240229"), "claude-opus-4-20250514");
-  assert.equal(resolveModelAlias("claude-3-5-sonnet-latest"), "claude-sonnet-4-20250514");
+  // #11503: the previous targets (claude-opus-4-20250514 / claude-sonnet-4-20250514)
+  // were themselves retired on 2026-06-15. These are the replacements Anthropic publishes.
+  assert.equal(resolveModelAlias("claude-3-opus-20240229"), "claude-opus-4-8");
+  assert.equal(resolveModelAlias("claude-3-5-sonnet-latest"), "claude-sonnet-4-6");
 });
 
 test("resolveModelAlias: does not silently reroute retired OpenAI models", () => {