impact_of

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

Annotations already provide readOnly, idempotent, and non-destructive safety. The description adds meaningful behavioral detail beyond that, including the exactness of the count and file list and the 100-symbol cap. This helps set expectations without contradicting the annotations.

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 two sentences with no filler. The when-to-use guidance is front-loaded, followed by the precise return semantics and the cap/exactness caveat.

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?

With one well-documented parameter, rich annotations, and no output schema, the description fully covers what the agent needs: the use case, result set, file association, and truncation behavior. The ambiguity-refusal behavior is already in the schema, so nothing critical 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 coverage is 100%, and the schema already explains short vs. fully qualified names and the ambiguous-name refusal behavior. The description adds no new parameter-level semantics, so a baseline of 3 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 uses a specific verb and resource: 'Returns every symbol that transitively reaches this one and the files they live in,' clearly defining impact analysis. It also states the use case ('Call before a breaking change to size its blast radius'), which distinguishes it from direct-reference siblings like callers_of, callees_of, and references_of.

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?

It gives explicit when-to-use guidance: 'Call before a breaking change to size its blast radius.' It does not explicitly name alternative tools or give when-not-to-use conditions, but the transitive impact framing makes the intended context clear.

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