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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds value by stating that the tool returns both the category description and member CWE IDs, which is not present in the schema. It does not contradict annotations. This additional return-level transparency earns a 4.

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 most actionable information (example queries), then explains the resource and return value in one tight, purposeful sentence. There is no filler or repetition. It is long enough to be helpful but not bloated, and every clause adds context.

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-only fetch tool with an output schema present, the description is complete. It explains what the tool does, what it returns, and what the input means. The output schema handles return-field details, and annotations handle safety. Nothing an agent needs to invoke it correctly is missing.

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 0%, so the description must compensate. It does so by using the example 'CWE-1210' and referring to a 'category record', which clarifies that the single 'id' parameter expects a CWE category identifier (like CWE-1210). This gives the agent concrete format guidance beyond the bare schema, though it doesn't spell out the exact pattern or validation rules. A 4 is appropriate.

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 a specific verb ('fetch'), a resource ('CWE category record'), and the kind of data it returns (description plus member CWE IDs). It also gives concrete example queries, making the tool's purpose unmistakable. It distinguishes itself from siblings like 'weakness' by focusing on category-level groupings, even without naming the sibling explicitly.

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 embeds usage context through natural-language examples ('What CWEs fall under [category]', 'memory safety weaknesses'), which strongly imply when to use this tool. It doesn't explicitly contrast with alternatives like 'weakness' or 'children', but the query patterns effectively route the agent to the right context. A clear when-not-to-use note is missing, so it falls just short of a 5.

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