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

Annotations already mark the tool as read-only, idempotent, open-world, and non-destructive. The description adds meaningful behavioral context beyond this: no auth required, the exact set of returned fields, and that the description text is HTML-stripped. This exceeds what annotations alone provide and is consistent with them.

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 front-loaded with the purpose, then lists return fields, usage guidance, an example, and the auth note. Every sentence earns its place and there is no filler or redundancy.

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 single-parameter read tool with a full output schema and safety annotations, the description covers input discovery, auth, examples, and return data comprehensively. The only notable gap is the misnamed references to sibling discovery tools, which slightly weakens end-to-end completeness.

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?

The schema already documents volcano_id at 100% coverage, so the baseline is 3. The description adds value by giving concrete examples ('ak277' for Takawangha, '311120' for Great Sitkin) and telling the agent where to obtain valid IDs, going beyond the schema's basic description.

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 first sentence states a specific verb and resource: 'Get detailed information for a single US volcano by its USGS volcano code or Smithsonian vnum.' This clearly differentiates it from list-oriented siblings like volcano.catalog.us and from notice/alert tools in the same family.

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 explicitly tells the agent where to discover valid volcano IDs ('Use volcano.us_catalog or volcano.monitored'). However, the actual sibling names are volcano.catalog.us and volcano.status.monitored, so the referenced tool names are mismatched and could lead an agent to call non-existent tools. It also does not explicitly contrast with alternative detail/status tools.

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