StewReads MCP has 6 tools with generally clear naming and actionable descriptions. All tools have non-empty descriptions and explicit input schemas. However, several critical gaps limit production readiness: (1) Output schemas are not formally documented, the tool descriptions mention what will be returned (e.g., 'Saved ebook...') but do not specify structured output field types, which LLMs need to plan chaining; (2) Parameters lack comprehensive constraint documentation (e.g., output_dir accepts any string with no validation guidance, markdown size limits unstated); (3) Error handling is present but inconsistent, some tools return structured error objects with error_code/message, others rely on exceptions; (4) Some parameters have weak descriptions (e.g., filename: 'Optional custom filename for the EPUB (without extension)', does not specify max length, character restrictions, or conflict handling); (5) Tool composition is reasonable but save_ebook conflates EPUB generation, file I/O, and optional background audio generation, makes the tool do multiple things; (6) No tool annotations (readOnlyHint, destructiveHint, idempotentHint) present, which would clarify retry safety for agents.

• Document return types and field names for all tools. E.g., get_stew_config should return {ok: bool, output_dir: string, config_path: string, configured: bool, message: string}. Use JSON Schema format in tool metadata or docstrings.
• Add max length and character restrictions to string parameters. E.g., output_dir: 'Path to output folder (max 255 chars, absolute path required)', filename: 'Custom filename without extension (1-100 alphanumeric + underscore only)'.
• Split save_ebook into two tools: save_ebook (synchronous EPUB only) and create_audiobook (async, returns audio_path or background job ID). This aligns with single-responsibility principle and lets agents compose them explicitly.
• Add tool annotations via fastmcp decorator arguments or metadata. E.g., @mcp.tool(name='save_ebook', inputSchema={...}, annotations={'readOnly': False, 'destructive': True, 'idempotent': True}).
• Enhance error responses with recovery guidance. When save_ebook fails due to missing output_dir, return: {ok: False, error_code: 'config_error', message: '...', next_step: 'Call save_stew_config(output_dir="/path/to/folder") first, then retry save_ebook.'}
• Add enum constraints or regex patterns to email_ebook.to_email (email format validation), save_ebook.create_audio (boolean, clearly optional), and save_stew_config.output_dir (path exists check at invocation time or describe valid format).
• Document idempotency guarantees. If save_ebook with the same (markdown, title, filename) is called twice, does it overwrite the first EPUB or error? State this explicitly so agents know retry safety.