file_history

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior. The description adds useful behavioral context beyond those annotations: ordering ('newest first'), per-commit added/deleted line counts, and support for deleted files.

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, front-loaded with what the tool returns and how it is ordered. The trailing deleted-file note is a useful, non-redundant edge case, and every phrase earns its place.

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 full schema descriptions, an output schema, and read-only annotations, the description is complete enough for correct invocation. It covers purpose, ordering, return content, and the deleted-file edge case; the only gap is sibling routing, which belongs to usage guidelines.

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 repo alias, file path, and limit. The description adds no parameter syntax, defaults, or constraints beyond what the schema provides, making the baseline 3 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 states a specific resource (commits that changed a file) and scope (newest first, with added/deleted lines), plus an edge case (deleted files). It is clearly distinct from repo-wide siblings like repo_summary, hotspots, and author_activity, though it does not explicitly name an alternative to differentiate itself.

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?

No alternative tool is named and no 'use when' condition is given beyond the implicit file-history query. 'Works for deleted files too' is an edge-case capability, not routing guidance, so the agent gets no explicit when/when-not direction.

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