feat(claude): gate Mythos on advertised model identity

packages/cli/tests/15-provider.test.ts

@@ -62,11 +62,6 @@ const EXPECTED_CLAUDE_MODELS = [
     model: "Opus 5",
     descriptionFragment: "Previous release",
   },
-  {
-    id: "claude-mythos-5-1",
-    model: "Mythos 5.1",
-    descriptionFragment: "Requires verified access",
-  },
   {
     id: "claude-fable-5-1",
     model: "Fable 5.1",

packages/server/src/server/agent/providers/claude/agent.test.ts

@@ -426,6 +426,14 @@ describe("ClaudeAgentClient.fetchCatalog", () => {
     try {
       const client = new ClaudeAgentClient({
         logger,
+        discoverModels: async () => [
+          {
+            value: "mythos",
+            resolvedModel: "claude-mythos-5-1",
+            displayName: "Mythos",
+            description: "",
+          },
+        ],
         resolveBinary: async () => "/test/claude/bin",
         resolveVersion: async () => "2.1.219",
         runtimeSettings: { env: { CLAUDE_CONFIG_DIR: emptyConfigDir } },
@@ -473,6 +481,14 @@ describe("ClaudeAgentClient.fetchCatalog", () => {
     try {
       const client = new ClaudeAgentClient({
         logger,
+        discoverModels: async () => [
+          {
+            value: "mythos",
+            resolvedModel: "claude-mythos-5-1",
+            displayName: "Mythos",
+            description: "",
+          },
+        ],
         resolveVersion: async () => {
           throw new Error("unrecognized version output");
         },
@@ -496,6 +512,14 @@ describe("ClaudeAgentClient.fetchCatalog", () => {
     try {
       const client = new ClaudeAgentClient({
         logger,
+        discoverModels: async () => [
+          {
+            value: "mythos",
+            resolvedModel: "claude-mythos-5-1",
+            displayName: "Mythos",
+            description: "",
+          },
+        ],
         resolveBinary: async () => "/test/claude/bin",
         resolveVersion: async () => "2.1.293",
         runtimeSettings: { env: { CLAUDE_CONFIG_DIR: emptyConfigDir } },

packages/server/src/server/agent/providers/claude/agent.ts

@@ -76,6 +76,7 @@ import {
   type ClaudeProviderOptions,
 } from "./options.js";
 import { renderPromptAttachmentAsText } from "../../prompt-attachments.js";
+import { discoverClaudeModels } from "./model-discovery.js";
 import { claudeQuery, type ClaudeOptions, type ClaudeQueryFactory } from "./query.js";
 import {
   realClaudeRewindSdk,
@@ -412,6 +413,7 @@ export interface ClaudeContentChunk {
 }
 
 interface ClaudeAgentClientOptions {
+  discoverModels?: typeof discoverClaudeModels;
   defaults?: { agents?: Record<string, AgentDefinition> };
   logger: Logger;
   runtimeSettings?: ProviderRuntimeSettings;
@@ -1514,6 +1516,7 @@ export function readEventIdentifiers(message: SDKMessage): EventIdentifiers {
 }
 
 export class ClaudeAgentClient implements AgentClient {
+  private readonly discoverModels: typeof discoverClaudeModels;
   readonly provider = "claude" as const;
   readonly capabilities = CLAUDE_CAPABILITIES;
 
@@ -1526,6 +1529,7 @@ export class ClaudeAgentClient implements AgentClient {
   private readonly rewindSdk: ClaudeRewindSdk;
 
   constructor(options: ClaudeAgentClientOptions) {
+    this.discoverModels = options.discoverModels ?? discoverClaudeModels;
     this.defaults = options.defaults;
     this.logger = options.logger.child({ module: "agent", provider: "claude" });
     this.runtimeSettings = options.runtimeSettings;
@@ -1608,8 +1612,35 @@ export class ClaudeAgentClient implements AgentClient {
       this.logger.warn({ err: error }, "Failed to resolve Claude Code version for model catalog");
     }
     const env = this.buildProviderEnv();
+    let discoveredModelIds = new Set<string>();
+    try {
+      const advertisedModels = await runProviderRefreshActivity(context, "models", () =>
+        this.discoverModels({
+          resolveBinary: this.resolveBinary,
+          runtimeSettings: this.runtimeSettings,
+          env,
+          signal: context?.signal,
+        }),
+      );
+      discoveredModelIds = new Set(
+        advertisedModels
+          .map((model) => normalizeClaudeRuntimeModelId(model.resolvedModel ?? model.value))
+          .filter((id): id is string => id !== null),
+      );
+    } catch (error) {
+      context?.signal.throwIfAborted();
+      this.logger.warn(
+        { err: error },
+        "Claude model discovery failed; omitting discovery-required models",
+      );
+    }
     const models = await runProviderRefreshActivity(context, "settings", () =>
-      getClaudeModelsWithSettings(this.logger, claudeConfigDir(env), claudeCodeVersion),
+      getClaudeModelsWithSettings(
+        this.logger,
+        claudeConfigDir(env),
+        claudeCodeVersion,
+        discoveredModelIds,
+      ),
     );
     const modeCatalog = claudeModeCatalog(env);
     return {

packages/server/src/server/agent/providers/claude/model-discovery.ts

@@ -0,0 +1,89 @@
+import type { ChildProcess } from "node:child_process";
+import os from "node:os";
+import type { ModelInfo, Query, SDKUserMessage } from "@anthropic-ai/claude-agent-sdk";
+import { raceProviderRefreshAbort } from "../../provider-refresh-deadline.js";
+import type { ProviderRuntimeSettings } from "../../provider-launch-config.js";
+import { terminateWithTreeKill } from "../../../../utils/tree-kill.js";
+import { claudeQuery, type ClaudeQueryInput, type ClaudeQueryContext } from "./query.js";
+
+interface ClaudeModelDiscoveryOptions {
+  resolveBinary: () => Promise<string>;
+  runtimeSettings?: ProviderRuntimeSettings;
+  env: NodeJS.ProcessEnv;
+  signal?: AbortSignal;
+}
+
+type OpenDiscoveryQuery = (
+  input: ClaudeQueryInput,
+  context: ClaudeQueryContext,
+) => Pick<Query, "supportedModels" | "close">;
+
+// The curated catalog survives a failed or slow probe. This process never receives
+// a prompt and must not persist a session or launch user MCP servers/hooks.
+export async function discoverClaudeModels(
+  options: ClaudeModelDiscoveryOptions,
+  openQuery: OpenDiscoveryQuery = claudeQuery,
+): Promise<ModelInfo[]> {
+  const controller = new AbortController();
+  const signal = options.signal
+    ? AbortSignal.any([options.signal, controller.signal])
+    : controller.signal;
+  const timer = setTimeout(
+    () => controller.abort(new Error("Claude model discovery timed out")),
+    5_000,
+  );
+  let endInput!: () => void;
+  const ended = new Promise<void>((resolve) => {
+    endInput = resolve;
+  });
+  const input: AsyncIterable<SDKUserMessage> = {
+    [Symbol.asyncIterator]() {
+      return {
+        next: async () => {
+          await ended;
+          return { done: true, value: undefined };
+        },
+      };
+    },
+  };
+  let query: ReturnType<OpenDiscoveryQuery> | undefined;
+  let child: ChildProcess | undefined;
+  try {
+    signal.throwIfAborted();
+    const binary = await raceProviderRefreshAbort(signal, options.resolveBinary());
+    query = openQuery(
+      {
+        prompt: input,
+        options: {
+          pathToClaudeCodeExecutable: binary,
+          cwd: os.homedir(),
+          env: options.env,
+          persistSession: false,
+          tools: [],
+          mcpServers: {},
+          strictMcpConfig: true,
+          settingSources: ["user"],
+          settings: { disableAllHooks: true },
+          abortController: controller,
+        },
+      },
+      {
+        runtimeSettings: options.runtimeSettings,
+        onChildProcess: (process) => {
+          child = process;
+        },
+      },
+    );
+    return await raceProviderRefreshAbort(signal, query.supportedModels());
+  } finally {
+    clearTimeout(timer);
+    endInput();
+    try {
+      query?.close();
+    } finally {
+      if (child) {
+        await terminateWithTreeKill(child, { gracefulTimeoutMs: 200, forceTimeoutMs: 200 });
+      }
+    }
+  }
+}

packages/server/src/server/agent/providers/claude/model-manifest.ts

@@ -9,6 +9,7 @@ interface ClaudeModelManifestEntry {
   description: string;
   defaultPriority?: number;
   minimumClaudeCodeVersion?: string;
+  requiresDiscovery?: boolean;
   contextWindowMaxTokens?: number;
   effortLevels?: readonly ClaudeEffortLevel[];
   defaultThinkingOptionId?: ClaudeEffortLevel;
@@ -60,6 +61,7 @@ export const CLAUDE_MODEL_MANIFEST = [
   {
     id: "claude-mythos-5-1",
     label: "Mythos 5.1",
+    requiresDiscovery: true,
     description: "Mythos 5.1 · Requires verified access",
     contextWindowMaxTokens: 1_000_000,
     effortLevels: CLAUDE_EFFORT_LEVELS.xhigh,
@@ -224,9 +226,16 @@ function buildThinkingOptions(
   return options;
 }
 
-export function getClaudeManifestModels(claudeCodeVersion?: string): AgentModelDefinition[] {
+export function getClaudeManifestModels(
+  claudeCodeVersion?: string,
+  discoveredModelIds?: ReadonlySet<string>,
+): AgentModelDefinition[] {
   const availableModels: readonly ClaudeModelManifestEntry[] = CLAUDE_MODEL_MANIFEST.filter(
-    (model) => isModelAvailableInClaudeCode(model, claudeCodeVersion),
+    (model) =>
+      isModelAvailableInClaudeCode(model, claudeCodeVersion) &&
+      (discoveredModelIds === undefined ||
+        !("requiresDiscovery" in model && model.requiresDiscovery) ||
+        discoveredModelIds.has(model.id)),
   );
   const defaultModel = availableModels.reduce<ClaudeModelManifestEntry | undefined>(
     (selected, candidate) =>

packages/server/src/server/agent/providers/claude/models.test.ts

@@ -13,6 +13,8 @@ import {
   parseClaudeCodeVersion,
   resolveClaudeDisabledThinkingForModel,
 } from "./model-manifest.js";
+import { discoverClaudeModels } from "./model-discovery.js";
+import type { ModelInfo } from "@anthropic-ai/claude-agent-sdk";
 import { findClaudeModel, getClaudeModels, normalizeClaudeRuntimeModelId } from "./models.js";
 
 const createdClaudeConfigDirs: string[] = [];
@@ -43,6 +45,14 @@ function createCatalogClient(claudeCodeVersion = "2.1.293"): ClaudeAgentClient {
   return new ClaudeAgentClient({
     logger: createTestLogger(),
     resolveVersion: async () => claudeCodeVersion,
+    discoverModels: async () => [
+      {
+        value: "mythos",
+        resolvedModel: "claude-mythos-5-1",
+        displayName: "Mythos",
+        description: "",
+      },
+    ],
   });
 }
 
@@ -223,6 +233,116 @@ describe("getClaudeModels", () => {
 });
 
 describe("ClaudeAgentClient.fetchCatalog", () => {
+  it.each([
+    { value: "mythos", resolvedModel: "claude-mythos-5-1", expected: true },
+    { value: "claude-mythos-5-1", expected: true },
+    { value: "claude-mythos-5-1[1m]", expected: true },
+    { value: "global.anthropic.claude-mythos-5-1", expected: true },
+    { value: "mythos", expected: false },
+    { value: "mythos", resolvedModel: "claude-mythos-5-2", expected: false },
+    { value: "claude-mythos-5-1", resolvedModel: "claude-fable-5-1", expected: false },
+  ])(
+    "uses advertised identity $value / $resolvedModel to gate Mythos",
+    async ({ value, resolvedModel, expected }) => {
+      const configDir = await createClaudeConfigDir({});
+      const client = new ClaudeAgentClient({
+        logger: createTestLogger(),
+        resolveVersion: async () => "2.1.293",
+        runtimeSettings: { env: { CLAUDE_CONFIG_DIR: configDir } },
+        discoverModels: async () => [
+          { value, resolvedModel, displayName: "Untrusted label", description: "" },
+        ],
+      });
+      const { models } = await client.fetchCatalog({
+        scope: "workspace",
+        cwd: configDir,
+        force: false,
+      });
+      expect(models.find((model) => model.id === "claude-mythos-5-1")).toEqual(
+        expected ? findClaudeModel("claude-mythos-5-1") : undefined,
+      );
+    },
+  );
+
+  it("preserves the curated catalog and explicitly configured models after discovery failure", async () => {
+    const configDir = await createClaudeConfigDir({ model: "claude-mythos-5-1" });
+    const client = new ClaudeAgentClient({
+      logger: createTestLogger(),
+      resolveVersion: async () => "2.1.293",
+      runtimeSettings: { env: { CLAUDE_CONFIG_DIR: configDir } },
+      discoverModels: async () => {
+        throw new Error("discovery unavailable");
+      },
+    });
+    const { models } = await client.fetchCatalog({
+      scope: "workspace",
+      cwd: configDir,
+      force: false,
+    });
+    expect(models.filter((model) => model.id !== "claude-mythos-5-1")).toEqual(
+      getClaudeModels("2.1.293").filter((model) => model.id !== "claude-mythos-5-1"),
+    );
+    expect(models.find((model) => model.id === "claude-mythos-5-1")?.description).toBe(
+      "From Claude settings.json model",
+    );
+  });
+
+  it("omits unconfirmed Mythos after a failed probe and retries on refresh", async () => {
+    const configDir = await createClaudeConfigDir({});
+    let fail = true;
+    const client = new ClaudeAgentClient({
+      logger: createTestLogger(),
+      resolveVersion: async () => "2.1.293",
+      runtimeSettings: { env: { CLAUDE_CONFIG_DIR: configDir } },
+      discoverModels: async () => {
+        if (fail) throw new Error("discovery unavailable");
+        return [
+          {
+            value: "mythos",
+            resolvedModel: "claude-mythos-5-1",
+            displayName: "Mythos",
+            description: "",
+          },
+        ];
+      },
+    });
+    const options = { scope: "workspace" as const, cwd: configDir, force: true };
+    expect(
+      (await client.fetchCatalog(options)).models.some((model) => model.id === "claude-mythos-5-1"),
+    ).toBe(false);
+    fail = false;
+    expect(
+      (await client.fetchCatalog(options)).models.find((model) => model.id === "claude-mythos-5-1"),
+    ).toEqual(findClaudeModel("claude-mythos-5-1"));
+  });
+
+  it("keeps the curated catalog when discovery does not advertise Mythos", async () => {
+    const configDir = await createClaudeConfigDir({});
+    const client = new ClaudeAgentClient({
+      logger: createTestLogger(),
+      resolveVersion: async () => "2.1.293",
+      runtimeSettings: { env: { CLAUDE_CONFIG_DIR: configDir } },
+      discoverModels: async () => [
+        {
+          value: "opus",
+          resolvedModel: "claude-opus-5-5",
+          displayName: "Opus",
+          description: "Latest",
+        },
+      ],
+    });
+    const { models } = await client.fetchCatalog({
+      scope: "workspace",
+      cwd: configDir,
+      force: false,
+    });
+    expect(models.map((model) => model.id)).toEqual(
+      getClaudeModels("2.1.293")
+        .filter((model) => model.id !== "claude-mythos-5-1")
+        .map((model) => model.id),
+    );
+  });
+
   it("appends concrete models from Claude settings.json", async () => {
     const configDir = await createClaudeConfigDir({
       model: "us.anthropic.claude-opus-4-7[1m]",
@@ -300,6 +420,7 @@ describe("ClaudeAgentClient.fetchCatalog", () => {
     const client = new ClaudeAgentClient({
       logger: createTestLogger(),
       resolveVersion: async () => "2.1.280",
+      discoverModels: async () => [],
       runtimeSettings: { env: { CLAUDE_CONFIG_DIR: providerConfigDir } },
     });
 
@@ -773,3 +894,77 @@ describe("Claude Mythos 5.1 catalog", () => {
     },
   );
 });
+
+describe("Claude model discovery process", () => {
+  it("does not send a prompt or persist a session and closes after discovery", async () => {
+    let closed = false;
+    let promptEnded: Promise<IteratorResult<unknown>> | undefined;
+    const advertised: ModelInfo[] = [
+      {
+        value: "mythos",
+        resolvedModel: "claude-mythos-5-1",
+        displayName: "Mythos",
+        description: "",
+      },
+    ];
+    const models = await discoverClaudeModels(
+      { resolveBinary: async () => "/claude", env: { CLAUDE_CONFIG_DIR: "/provider-config" } },
+      (input) => {
+        expect(input.options).toMatchObject({
+          pathToClaudeCodeExecutable: "/claude",
+          env: { CLAUDE_CONFIG_DIR: "/provider-config" },
+          persistSession: false,
+          tools: [],
+          mcpServers: {},
+          strictMcpConfig: true,
+          settingSources: ["user"],
+          settings: { disableAllHooks: true },
+        });
+        if (typeof input.prompt === "string") throw new Error("unexpected inference prompt");
+        promptEnded = input.prompt[Symbol.asyncIterator]().next();
+        return {
+          supportedModels: async () => advertised,
+          close: () => {
+            closed = true;
+          },
+        };
+      },
+    );
+    expect(models).toEqual(advertised);
+    expect(closed).toBe(true);
+    await expect(promptEnded).resolves.toEqual({ done: true, value: undefined });
+  });
+
+  it("times out and closes an unresponsive discovery process", async () => {
+    let closed = false;
+    await expect(
+      discoverClaudeModels({ resolveBinary: async () => "/claude", env: {} }, () => ({
+        supportedModels: () => new Promise(() => {}),
+        close: () => {
+          closed = true;
+        },
+      })),
+    ).rejects.toThrow("Claude model discovery timed out");
+    expect(closed).toBe(true);
+  }, 10_000);
+
+  it("closes a stalled probe when its refresh is canceled", async () => {
+    const controller = new AbortController();
+    const failure = new Error("refresh canceled");
+    let closed = false;
+    const result = discoverClaudeModels(
+      { resolveBinary: async () => "/claude", env: {}, signal: controller.signal },
+      () => ({
+        supportedModels: () => {
+          controller.abort(failure);
+          return new Promise(() => {});
+        },
+        close: () => {
+          closed = true;
+        },
+      }),
+    );
+    await expect(result).rejects.toBe(failure);
+    expect(closed).toBe(true);
+  });
+});

packages/server/src/server/agent/providers/claude/models.ts

@@ -52,8 +52,9 @@ export async function getClaudeModelsWithSettings(
   logger: Logger,
   configDir: string,
   claudeCodeVersion?: string,
+  discoveredModelIds: ReadonlySet<string> = new Set(),
 ): Promise<AgentModelDefinition[]> {
-  const hardcodedModels = getClaudeModels(claudeCodeVersion);
+  const hardcodedModels = getClaudeManifestModels(claudeCodeVersion, discoveredModelIds);
   const settingsModels = await readClaudeSettingsModels(logger, configDir);
   if (settingsModels.length === 0) {
     return hardcodedModels;