diff --git a/packages/server/src/server/agent/providers/claude/agent.test.ts b/packages/server/src/server/agent/providers/claude/agent.test.ts
index 16cd1e9131..e773cd7359 100644
--- a/packages/server/src/server/agent/providers/claude/agent.test.ts
+++ b/packages/server/src/server/agent/providers/claude/agent.test.ts
@@ -445,6 +445,29 @@ describe("ClaudeAgentClient.fetchCatalog", () => {
     }
   });
 
+  test("preserves the catalog when Claude Code version detection fails", async () => {
+    const emptyConfigDir = await fs.mkdtemp(path.join(os.tmpdir(), "paseo-claude-models-empty-"));
+    try {
+      const client = new ClaudeAgentClient({
+        logger,
+        resolveVersion: async () => {
+          throw new Error("unrecognized version output");
+        },
+        configDir: emptyConfigDir,
+      });
+      const { models } = await client.fetchCatalog({
+        scope: "workspace",
+        cwd: "/tmp/claude-models",
+        force: false,
+      });
+
+      expect(models.find((model) => model.isDefault)?.id).toBe("claude-opus-5[1m]");
+      expect(models.map((model) => model.id)).toContain("claude-fable-5[1m]");
+    } finally {
+      await fs.rm(emptyConfigDir, { recursive: true, force: true });
+    }
+  });
+
   test("exposes Ultra Code on xhigh-capable Claude models", async () => {
     const emptyConfigDir = await fs.mkdtemp(path.join(os.tmpdir(), "paseo-claude-models-empty-"));
     try {
diff --git a/packages/server/src/server/agent/providers/claude/agent.ts b/packages/server/src/server/agent/providers/claude/agent.ts
index 754316b0d5..463540825d 100644
--- a/packages/server/src/server/agent/providers/claude/agent.ts
+++ b/packages/server/src/server/agent/providers/claude/agent.ts
@@ -364,7 +364,7 @@ interface ClaudeAgentClientOptions {
   runtimeSettings?: ProviderRuntimeSettings;
   queryFactory?: ClaudeQueryFactory;
   resolveBinary?: () => Promise<string>;
-  resolveVersion?: () => Promise<string | null>;
+  resolveVersion?: () => Promise<string>;
   configDir?: string;
 }
 
@@ -1441,7 +1441,7 @@ export class ClaudeAgentClient implements AgentClient {
   private readonly runtimeSettings?: ProviderRuntimeSettings;
   private readonly queryFactory?: ClaudeQueryFactory;
   private readonly resolveBinary: () => Promise<string>;
-  private readonly resolveVersion: () => Promise<string | null>;
+  private readonly resolveVersion: () => Promise<string>;
   private readonly configDir?: string;
 
   constructor(options: ClaudeAgentClientOptions) {
@@ -1503,7 +1503,7 @@ export class ClaudeAgentClient implements AgentClient {
 
   async fetchCatalog(_options: FetchCatalogOptions): Promise<ProviderCatalog> {
     // Claude exposes a global catalog here; cwd/force are intentionally irrelevant.
-    let claudeCodeVersion: string | null = null;
+    let claudeCodeVersion: string | undefined;
     try {
       claudeCodeVersion = await this.resolveVersion();
     } catch (error) {
@@ -1637,14 +1637,14 @@ async function resolveClaudeBinary(runtimeSettings?: ProviderRuntimeSettings): P
 
 export async function resolveClaudeCodeVersion(
   runtimeSettings?: ProviderRuntimeSettings,
-): Promise<string | null> {
+): Promise<string> {
   const launch = await resolveProviderLaunch({
     commandConfig: runtimeSettings?.command,
     defaultBinary: "claude",
   });
   const availability = await checkProviderLaunchAvailable(launch);
   if (!availability.available) {
-    return null;
+    throw new Error("Claude binary not found while resolving Claude Code version");
   }
   const executable = availability.resolvedPath ?? launch.command;
   const { stdout, stderr } = await execCommand(executable, [...launch.args, "--version"], {
@@ -1652,7 +1652,10 @@ export async function resolveClaudeCodeVersion(
     timeout: 5_000,
   });
   const version = parseClaudeCodeVersion(`${stdout}\n${stderr}`);
-  return version?.join(".") ?? null;
+  if (!version) {
+    throw new Error("Unable to parse Claude Code version from --version output");
+  }
+  return version.join(".");
 }
 
 async function resolveClaudeAuth(
diff --git a/packages/server/src/server/agent/providers/claude/model-manifest.ts b/packages/server/src/server/agent/providers/claude/model-manifest.ts
index 1b14469dcd..9c81a1d508 100644
--- a/packages/server/src/server/agent/providers/claude/model-manifest.ts
+++ b/packages/server/src/server/agent/providers/claude/model-manifest.ts
@@ -184,7 +184,7 @@ function buildThinkingOptions(
   return options;
 }
 
-export function getClaudeManifestModels(claudeCodeVersion?: string | null): AgentModelDefinition[] {
+export function getClaudeManifestModels(claudeCodeVersion?: string): AgentModelDefinition[] {
   const availableModels: readonly ClaudeModelManifestEntry[] = CLAUDE_MODEL_MANIFEST.filter(
     (model) => isModelAvailableInClaudeCode(model, claudeCodeVersion),
   );
@@ -221,14 +221,11 @@ export function getClaudeManifestModels(claudeCodeVersion?: string | null): Agen
 
 function isModelAvailableInClaudeCode(
   model: ClaudeModelManifestEntry,
-  claudeCodeVersion: string | null | undefined,
+  claudeCodeVersion: string | undefined,
 ): boolean {
   if (!model.minimumClaudeCodeVersion || claudeCodeVersion === undefined) {
     return true;
   }
-  if (claudeCodeVersion === null) {
-    return false;
-  }
   return compareVersions(claudeCodeVersion, model.minimumClaudeCodeVersion) >= 0;
 }
 
diff --git a/packages/server/src/server/agent/providers/claude/models.ts b/packages/server/src/server/agent/providers/claude/models.ts
index f1749cc787..48bf900884 100644
--- a/packages/server/src/server/agent/providers/claude/models.ts
+++ b/packages/server/src/server/agent/providers/claude/models.ts
@@ -17,7 +17,7 @@ const CLAUDE_SETTINGS_MODEL_ENV_KEYS = [
   "ANTHROPIC_DEFAULT_HAIKU_MODEL",
 ] as const;
 
-export function getClaudeModels(claudeCodeVersion?: string | null): AgentModelDefinition[] {
+export function getClaudeModels(claudeCodeVersion?: string): AgentModelDefinition[] {
   return getClaudeManifestModels(claudeCodeVersion);
 }
 
@@ -34,7 +34,7 @@ export function findClaudeModel(
 export async function getClaudeModelsWithSettings(
   logger: Logger,
   configDir?: string,
-  claudeCodeVersion?: string | null,
+  claudeCodeVersion?: string,
 ): Promise<AgentModelDefinition[]> {
   const hardcodedModels = getClaudeModels(claudeCodeVersion);
   const settingsModels = await readClaudeSettingsModels(logger, configDir);