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

No annotations are provided, so the description carries the full burden. It discloses the return content and the API key requirement, and the verb 'fetch' implicitly indicates a read operation. However, it does not mention non-existence handling, rate limits, or other potential behaviors, which would strengthen transparency for a tool with no annotation support.

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 a single, focused sentence that front-loads the primary action and return value, with the API key requirement appended succinctly. Every word contributes value, with no redundancy or filler.

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 simple single-parameter fetch operation with no output schema, the description provides sufficient context: it states the exact input (id), what it returns (YAML source and metadata), and the auth requirement. It does not explain error cases, but that is acceptable given the tool's simplicity and the rich sibling context.

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% since the 'id' parameter is documented as 'Diagram id'. The description adds minimal extra meaning by clarifying the id is used to fetch one diagram and returns its YAML, but this largely restates the schema. Baseline of 3 is appropriate given the schema already covers the parameter.

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 ('one of the user's diagrams by id'), and specifies the return content (YAML source and metadata). This distinguishes it from sibling tools like list_diagrams and search_diagrams, which have different scopes.

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 implies when to use this tool: when you have a specific diagram id and need its YAML source and metadata. It also mentions the API key requirement, providing useful context. However, it does not explicitly name alternatives or exclusions, such as using list_diagrams for all diagrams.

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