where_used

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

With no annotations provided, the description carries the full burden. It discloses that resolution is by bare name only, that unrelated same-name symbols are grouped together, and that results include the indexed commit and whether checkout has moved on. It lacks explicit statements about permissions or rate limits, but given this is a read-only query tool, the behavioral disclosure is strong.

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 compact but information-dense. Every sentence earns its place: purpose, usage timing, alternative, read-only nature, important caveat, and expected reply format. It is front-loaded with the primary question and blast-radius framing, making it easy to scan.

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?

The description tells the agent what it will get (every definition and use site as file:line, indexed commit, checkout state) and what caveats apply. It doesn't explicitly document the 'limit' parameter's effect on output, but the schema already describes that. Without an output schema, mentioning the reply shape is valuable. Minor gap: no statement about performance or large result handling beyond the limit default.

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%, so baseline is 3. The description adds useful semantic context about 'bare symbol name' and matching behavior, but does not add much beyond the schema's parameter descriptions. It clarifies the meaning of 'name' well enough, so a 3 is fair.

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 names a specific operation (finding definitions and uses of a symbol name) and clearly distinguishes this from the sibling 'outline', which is about file-level declarations. The verb 'answers who defines and who uses' and the explicit 'code lane' qualifier make the purpose unmistakable.

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 gives explicit guidance on when to use this tool: 'the question to ask before changing a function, struct or variable'. It also names the alternative, 'Use outline instead to see everything one file declares', and warns about the blast radius interpretation. It even advises opening files rather than treating the result list as a conclusion.

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