Fetch MCP Server

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

With no annotations provided, the description carries full burden for behavioral disclosure. While 'fetch' implies a read operation, it doesn't specify authentication requirements, rate limits, error handling, timeout behavior, or what happens with invalid URLs. The description is minimal and lacks crucial operational context for a network-dependent 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 perfectly concise - a single sentence with zero wasted words that communicates the core function. It's front-loaded with the essential information and doesn't include unnecessary elaboration.

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?

For a network tool with no annotations and no output schema, the description is insufficient. It doesn't explain what the tool returns (parsed JSON object? raw string? status codes?), error conditions, authentication needs, or performance characteristics. The agent lacks crucial information to use this tool effectively in real scenarios.

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?

Schema description coverage is 100%, so the schema already documents both parameters thoroughly. The description adds no additional parameter semantics beyond what's in the schema - it doesn't explain URL format requirements, header usage patterns, or provide examples. Baseline 3 is appropriate when schema does the documentation work.

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 action ('fetch') and resource ('a JSON file from a URL'), making the purpose immediately understandable. It distinguishes from siblings like fetch_html and fetch_markdown by specifying JSON format, but doesn't explicitly contrast with them or mention what makes this tool unique beyond format.

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?

No guidance is provided on when to use this tool versus alternatives like fetch_html or fetch_markdown. The description doesn't mention prerequisites, error conditions, or typical use cases, leaving the agent to infer usage context from the tool name alone.

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