Change Impact

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

Annotations already declare readOnlyHint=true, and the description adds useful behavioral context: it leaves the target repository unchanged, uses a per-user external cache, and can combine heuristic ranking with exact diff evidence. No contradiction with 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?

Two sentences with the main action and outputs front-loaded. Every sentence adds information: what the tool does, what it returns, when the optional diff base matters, and its cache/read-only behavior. No filler.

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?

There is no output schema, but the description explains the return payload components: ranked files, risk flags, suggested tests, and an implementation plan. It also notes the optional exact-evidence mode, external cache, and non-mutation, which is enough for an agent to select and invoke it correctly.

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 the schema already documents all parameters. The description adds meaning by characterizing query as a plain-English change request and diffBase as providing exact changed-file evidence alongside the heuristic, going beyond the schema.

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?

States a specific verb and resource: 'Given a plain-English change request, rank the files most likely to own the change' and enumerates the outputs (risk flags, suggested tests, implementation plan). This clearly distinguishes it from sibling repo inspection/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?

Clearly frames when to use the tool: when there is a plain-English change request, and when to use the optional diff base to surface exact changed-file evidence. It does not explicitly name alternatives or exclusions, but the usage context is unambiguous.

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