feat(sdk): add active provider discovery query

docs/sdk.md

@@ -410,6 +410,30 @@ with `requestedProfile` where applicable, whole exact `availableProfiles` entrie
 that fit the detail budget, and `discoveryQuery: "models.profiles.list"`. The
 discovery pointer is authoritative when the bounded error cannot include every ID.
 
+### Active provider query (Q29)
+
+`Q29` / `providers.list/active` pages the providers currently eligible for model
+selection through the same authenticated, retained-snapshot envelope as Q10. Each
+row is the non-secret DTO `{ provider, connectionKind }`, where `connectionKind`
+is `credential` or `credentialless`.
+
+Provider IDs are returned exactly as they appear in Q10 `model.provider`: existing
+mixed-case, spaced, punctuated, and long custom IDs are preserved without aliases
+or normalization. Rows are deduplicated and ordered by UTF-8 provider bytes.
+Join Q29 to Q10 by exact provider ID; Q10 remains the full configured catalog.
+
+A credentialed discovery-only provider appears only after fresh discovery proves
+the exact model is usable. Static configured models can appear without a network
+probe. The query never invokes a model, refreshes credentials, probes a remote
+account, or exposes credentials, account metadata, paths, or provider responses.
+
+Resolver failures are atomic and return
+`{ "code": "internal", "message": "Unable to resolve active providers." }`.
+They omit a page and restart metadata. An expired continuation follows the shared
+cursor contract and returns `error.code: "cursor_expired"` with
+`error.restartQuery: true`. Malformed cursor strings return `invalid_cursor`;
+cross-query or selector mismatches return `invalid_input`.
+
 ## Answer semantics
 
 A remote reply answers a pending ask in every session state:

packages/ai/CHANGELOG.md

@@ -5,6 +5,9 @@
 
 - Added read-only OpenCodex provider discovery with runtime-port resolution, identity-checked health probing, cached `/api/models` catalogs, raw wire model ids, and `/login opencodex` status reprobes without credential persistence.
 
+### Changed
+
+- OpenAI-compatible discovery and OpenAI Completions/Responses transports now preserve query-bearing endpoint routing, including repeated query parameters. Model resolution records whether a provider discovery result was fetched so consumers can distinguish current discovery evidence from cached data.
 
 ### Fixed