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

Annotations already indicate read-only and idempotent behavior. The description adds important context about the data source (parsed call graph) and the guarantee of completeness, which goes beyond the annotations. The parameter description also discloses grouping behavior for name collisions, adding transparency about result organization.

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?

Two sentences with no wasted words. The first sentence states purpose and key guarantee; the second frames usage context. Front-loaded and easy to parse.

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 query tool with an output schema, the description sufficiently covers what it returns (complete call list), when to use it, and its accuracy guarantee. It doesn't describe return formatting, but that's handled by the output schema. Slight additional context about error cases could be added, but overall very complete.

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%, and the function_name parameter description is detailed (bare name example, grouping logic). The tool description itself doesn't add parameter-level details, so the baseline of 3 applies per the rubric.

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 tool lists every place that calls a given function/method, derived from the parsed call graph. It distinguishes itself from siblings by emphasizing completeness ('not a best-effort guess') and by focusing on callers rather than callees, dependencies, definitions, or text search.

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?

Explicit guidance is provided: use before renaming/changing a function's signature or to understand blast radius before modifying. This clearly indicates when the tool is appropriate, and the contrast with siblings (e.g., get_callees) implies when it is not needed.

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