JuliusBrussee/caveman · error · Error

cave_claude_tool_schema_unsupported:${item.name}

Error message

cave_claude_tool_schema_unsupported:${item.name}

What it means

Error "cave_claude_tool_schema_unsupported:${item.name}" thrown in JuliusBrussee/caveman.

Source

Thrown at packages/agent/src/claude-runtime.ts:151

    // lane can only ever be an unlocked run: a missing gateway degrades to
    // observe-only rather than blocking a first response.
    const { useGateway } = await resolveCaveRoute(gatewayURL, options, false);
    const instructions = assembleSystemPrompt(definition, lowered);
    const runID = crypto.randomUUID();
    const sessionID = `claude-${definition.id}-${runID}`;
    const prefixSHA256 = sha256(stableStringify({
      instructions,
      tools: definition.tools.map((item) => ({
        name: item.name,
        description: item.description,
        input: item.input,
      })),
    }));
    const toolNames = new Set<string>();
    const mcpTools = definition.tools.map((item) => {
      const converted = z.fromJSONSchema(item.input as Record<string, unknown>);
      if (!(converted instanceof z.ZodObject)) {
        throw new Error(`cave_claude_tool_schema_unsupported:${item.name}`);
      }
      const execute = createHarnessToolExecutor({
        definition,
        tool: item,
        sandbox,
        ...(options.sandboxProfile === undefined ? {} : { sandboxProfile: options.sandboxProfile }),
        ...(options.engineBin === undefined ? {} : { engineBin: options.engineBin }),
      });
      const wireName = `mcp__caveman_agent__${item.name}`;
      toolNames.add(wireName);
      return claudeTool(
        item.name,
        item.description,
        converted.shape,
        async (args) => {
          const value = await execute(args, controller.signal);
          if (!isRecord(value) || !Array.isArray(value.content)) {
            throw new Error(`cave_claude_tool_result_invalid:${item.name}`);

View on GitHub (pinned to 27d5a3981a)

Solutions

1. The named tool's input schema cannot be mapped to the Claude tool format; simplify the schema to supported JSON Schema constructs.

When it happens

Trigger: Thrown at packages/agent/src/claude-runtime.ts:151 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of JuliusBrussee/caveman@27d5a3981a (2026-08-15). Data as JSON: /api/errors/60be3d68cd65b8f7. Report an issue: GitHub.