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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is clear. The description adds that comparisons are evidence-backed and objective, and that only approved tools can be compared, but it does not explain behavior such as error handling for invalid IDs or how locale affects results.

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, front-loaded sentence with no filler. It conveys the action, the resource, the count range, and the evidence-based nature of the output in minimal space.

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 read-only comparison tool whose schema already documents the UUID list and locale enum, the description plus annotations cover most invocation needs. The main missing pieces are the output shape and the precise meaning of 'approved', but the tool is otherwise simple enough to be adequately specified.

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 should compensate for the lack of parameter documentation. It adds 'distinct' and 'approved' semantics for toolIds but does not explain the locale parameter or elaborate on what 'approved tools' means, leaving a meaningful gap.

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 states a specific verb ('Compare'), a clear resource ('tools'), and an explicit constraint (2 to 5 distinct approved tools). It also signals the output nature ('evidence-backed objective facts'), which distinguishes it from sibling tools like get_tool or search_tools.

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 the tool is used for comparing multiple tools, and the '2 to 5' constraint gives some usage context. However, it does not explicitly state when to prefer compare_tools over search_tools or get_tool, nor does it mention any exclusions or alternative conditions.

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