Bookworm is a Rust-based MCP server for querying Rust crate documentation. All 5 tools have proper verb-prefix naming (search_*, crate_*) and input schemas with types. Descriptions are present but vary in quality. The server demonstrates competent engineering with modular crate architecture, proper use of schemars for schema generation, and thoughtful response size limiting (256 KiB). However, several parameter descriptions are minimal, output schemas are not documented, and error handling lacks recovery guidance. Tool composition is sound, tools are single-responsibility and well-separated. No security issues detected (read-only operations, no secret parameters). STDIO-only transport limits accessibility.

• Document the output schema for each tool. In tool descriptions or via a separate schema section, specify returned fields (e.g., 'Returns a JSON object with fields: crate_name (string), version (string), downloads (integer), updated_at (ISO 8601 date)'). LLMs need to know what to extract before calling.
• Expand parameter descriptions to 50-100 characters and include format/constraint details. E.g. 'The exact name of the crate (alphanumeric + underscore, case-insensitive, 1-64 chars)' instead of 'The exact name of the crate.'
• Replace 'kinds' example values with an enum declaration: {"type": "array", "items": {"enum": ["Struct", "Enum", "Trait", "Function", "Macro", "Method"]}}. This prevents hallucinated item kinds.
• Redesign crate_resource description to lead with intent: 'Get documentation, source code, or metadata for a Rust crate. Use this to read README, list items, or examine source files.' Then document URI patterns as a secondary reference.
• Add pagination and truncation handling. If responses exceed 256 KiB, document a truncation marker and provide a tool or parameter (e.g., offset/page) to fetch remaining results. Otherwise, LLMs may not realize results are partial.
• Add error recovery guidance. E.g., 'If a crate is not found, search_crates() with a partial name to locate alternatives.' This guides LLM retry behavior.
• Consider splitting crate_resource into separate tools (crate_readme, crate_metadata, crate_items) to reduce conceptual overhead. A single tool accepting 10 different URI patterns is harder for LLMs to reason about than 3 focused tools.

Inferred effective spec: <=2025-11-25.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry