mcp-fetch

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the two-phase protocol (start with URL, continue with transfer_id+offset) and chunked transfer behavior. It mentions timeout_ms and chunk_bytes parameters in the schema but doesn't fully explain their behavioral implications. The description doesn't cover authentication requirements, rate limits, or error handling, which would be helpful for a generic HTTP tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is well-structured with clear sections: a purpose statement, numbered usage guidelines, a note about alternatives, and a protocol explanation. Every sentence serves a distinct purpose with zero waste. The information is front-loaded with the most important guidance appearing first.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (11 parameters, no annotations, but with output schema), the description provides good contextual coverage. It explains the core purpose, when to use it, when to use alternatives, and the two-phase protocol. The existence of an output schema means the description doesn't need to explain return values. However, for a generic HTTP tool with many parameters, more guidance on parameter usage would be beneficial.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 0% schema description coverage for 11 parameters, the description provides minimal parameter semantics. It mentions 'url (required)' and the two-phase protocol involving 'transfer_id' and 'offset', but doesn't explain the purpose or usage of most other parameters like method, headers, query, body, json_body, timeout_ms, to_markdown, or chunk_bytes. The description adds some value but doesn't adequately compensate for the complete lack of schema descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose as performing generic HTTP requests for APIs or raw data, specifying multiple HTTP methods (GET, POST, PUT, DELETE, etc.). It explicitly distinguishes from its sibling tool 'fetch_page' by noting that tool is for renderable web pages with dynamic content and JavaScript, while this tool is for REST APIs and raw file downloads.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit usage guidelines with three numbered scenarios: calling REST APIs, using non-GET HTTP methods, and downloading raw files. It also includes a clear 'Note' section specifying when NOT to use this tool (for GET requests to renderable web pages) and explicitly names the alternative tool 'fetch_page'.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.