- OpenAI Codex/models: normalize stale native transport metadata in both runtime resolution and discovery/listing so legacy `openai-codex` rows with missing `api` or `https://chatgpt.com/backend-api/v1` self-heal to the canonical Codex transport instead of routing requests through broken HTML/Cloudflare paths, combining the original fixes proposed in #66969 (saamuelng601-pixel) and #67159 (hclsys). (#67635)

- Agents/failover: treat HTML provider error pages as upstream transport failures for CDN-style 5xx responses without misclassifying embedded body text as API rate limits, while still preserving auth remediation for HTML 401/403 pages and proxy remediation for HTML 407 pages. (#67642) Thanks @stainlu.

- Gateway/skills: bump the cached skills-snapshot version whenever a config write touches `skills.*` (for example `skills.allowBundled`, `skills.entries.<id>.enabled`, or `skills.profile`). Existing agent sessions persist a `skillsSnapshot` in `sessions.json` that reuses the skill list frozen at session creation; without this invalidation, removing a bundled skill from the allowlist left the old snapshot live and the model kept calling the disabled tool, producing `Tool <name> not found` loops that ran until the embedded-run timeout. (#67401) Thanks @xantorres.

- Agents/tool-loop: enable the unknown-tool stream guard by default. Previously `resolveUnknownToolGuardThreshold` returned `undefined` unless `tools.loopDetection.enabled` was explicitly set to `true`, which left the protection off in the default configuration. A hallucinated or removed tool (for example `himalaya` after it was dropped from `skills.allowBundled`) would then loop "Tool X not found" attempts until the full embedded-run timeout. The guard has no false-positive surface because it only triggers on tools that are objectively not registered in the run, so it now stays on regardless of `tools.loopDetection.enabled` and still accepts `tools.loopDetection.unknownToolThreshold` as a per-run override (default 10). (#67401) Thanks @xantorres.

## 2026.4.15-beta.1

});

describe("resolveUnknownToolGuardThreshold", () => {

it("returns undefined when loop detection is disabled", () => {

expect(resolveUnknownToolGuardThreshold({ enabled: false, unknownToolThreshold: 4 })).toBe(

undefined,

);

expect(resolveUnknownToolGuardThreshold(undefined)).toBe(undefined);

it("returns the default threshold when no loop-detection config is provided", () => {

expect(resolveUnknownToolGuardThreshold(undefined)).toBe(10);

expect(resolveUnknownToolGuardThreshold({})).toBe(10);

});

it("uses the default threshold when loop detection is enabled without an override", () => {

expect(resolveUnknownToolGuardThreshold({ enabled: true })).toBe(10);

it("stays on even when tools.loopDetection.enabled is false (safety net)", () => {

// The unknown-tool guard has no false-positive surface — the tool is

// objectively not registered — so it is always on regardless of the

// opt-in genericRepeat/pingPong/pollNoProgress detectors.

expect(resolveUnknownToolGuardThreshold({ enabled: false })).toBe(10);

expect(resolveUnknownToolGuardThreshold({ enabled: false, unknownToolThreshold: 3 })).toBe(3);

});

it("uses the configured threshold override when provided", () => {

expect(resolveUnknownToolGuardThreshold({ enabled: true, unknownToolThreshold: 4 })).toBe(4);

});

it("falls back to the default threshold when the override is non-positive", () => {

expect(resolveUnknownToolGuardThreshold({ unknownToolThreshold: 0 })).toBe(10);

expect(resolveUnknownToolGuardThreshold({ unknownToolThreshold: -5 })).toBe(10);

expect(

resolveUnknownToolGuardThreshold({ unknownToolThreshold: Number.NaN }),

).toBe(10);

});

it("floors fractional overrides", () => {

expect(resolveUnknownToolGuardThreshold({ unknownToolThreshold: 3.7 })).toBe(3);

});

});

describe("wrapStreamFnTrimToolCallNames", () => {

export function resolveUnknownToolGuardThreshold(loopDetection?: {

enabled?: boolean;

unknownToolThreshold?: number;

}): number | undefined {

if (loopDetection?.enabled !== true) {

return undefined;

}): number {

// The unknown-tool guard is a safety net against the model hallucinating a

// tool name or calling a tool that has since been removed from the allowlist

// (for example after a `skills.allowBundled` config change). After `threshold`

// consecutive unknown-tool attempts the stream wrapper rewrites the assistant

// message content to tell the model to stop, which breaks otherwise-infinite

// Tool-not-found loops against the provider. Unlike the genericRepeat /

// pingPong / pollNoProgress detectors this guard has no false-positive

// surface because the tool is objectively not registered in this run, so it

// stays on regardless of `tools.loopDetection.enabled`.

const raw = loopDetection?.unknownToolThreshold;

if (typeof raw === "number" && Number.isFinite(raw) && raw > 0) {

return Math.floor(raw);

}

return loopDetection.unknownToolThreshold ?? UNKNOWN_TOOL_THRESHOLD;

return UNKNOWN_TOOL_THRESHOLD;

}

function summarizeMessagePayload(msg: AgentMessage): { textChars: number; imageBlocks: number } {