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

With no annotations, the description carries the transparency burden and does a solid job: it discloses the core return value (Mermaid source), the conditional public image requiring an API key, and the TREE/FLOW modes. It stops short of describing error behavior or exact response shape, but for a non-destructive transformation tool this is adequate.

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 three short, front-loaded sentences. Each sentence adds a distinct piece of information: core function, output/API-key behavior, and supported modes. There is no wasted wording.

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?

Because there is no output schema, the description must explain return values, and it does. It covers the essential output behavior, API-key dependency, and diagram types. It does not specify the exact response envelope or failure modes, but for a straightforward transform tool with complete parameter schema coverage this is largely sufficient.

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?

All three parameters have schema descriptions, so the baseline is 3. The description adds no meaningful parameter information beyond what the schema already provides—it merely restates the diagramType enum values without extra syntax or usage nuance.

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 uses a specific verb-object pair ('Turn YAML into a diagram') and clearly differentiates from siblings by stating it returns Mermaid source and optionally a hosted public image. It also names the two supported diagram types, making the purpose unmistakable.

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 convert_yaml, create_diagram, or validate_yaml. The description explains what the tool does but does not mention exclusions, prerequisites, or alternative tools for related scenarios.

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