bb_get_diffstat

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

No annotations are provided, so the description carries the burden. It reveals that the tool returns a per-file summary, which is behavioral. However, it does not disclose potential behaviors like how a single commit diffs against its parent, the meaning of the 'topic' flag, or any side effects. The 'Get' verb implies a read operation, but additional context is minimal.

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, concise sentence that front-loads the tool's purpose and key usage. Every word adds value, with 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?

The tool has 8 parameters, all documented in the schema. While the description is brief, it gives a clear one-liner of the tool's purpose and the core spec format. The lack of an output schema is mitigated by the description's 'per-file change summary' hint, which sets expectations. However, subtle features like the 'topic' flag's 3-dot diff behavior are left to the schema, which is acceptable given the schema's richness.

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?

The input schema provides full descriptions for all 8 parameters, including the exact semantics of 'spec', 'topic', and 'filter'. The description briefly reinforces the spec syntax but adds no new meaning beyond the schema. Per the baseline for high schema coverage, this scores a 3.

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's function: retrieving a per-file change summary (diffstat) between commits. It uses a specific verb ('Get') and resource, distinguishing it from PR-specific diffstat tools like bb_get_pull_request_diffstat by scoping it to commits.

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 instructs how to specify commits ('Use a single commit hash or "commit1..commit2"'), which is a guideline for the spec parameter. However, it does not explicitly contrast with sibling tools like bb_get_diff or state when to prefer this tool over alternatives. The 'between commits' phrasing implies context but lacks explicit exclusions.

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