get_branch_diffs

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

The description discloses it is read-only and does not mutate data, and explicitly lists error conditions: missing resources, invalid identifiers, insufficient permission, and rate limits. While annotations already provide readOnlyHint, the description adds the error behavior specifics which is genuinely useful beyond the annotations. 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?

Three sentences, no redundancy. It front-loads the purpose, then routes alternatives, then disclaimers and identifier guidance. Every sentence adds distinct value; could be slightly trimmed but it is efficient.

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?

For a diff tool with 5 params and no output schema, the description covers usage discrimination, error behavior, and parameter use. It doesn't describe return format, which is implied by the tool name, and annotations cover read-only and open-world hints. Slightly short of a 5 because it doesn't hint at what the diff result contains (e.g., files changed, patches), but strong overall.

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%, so this is the baseline 3. The description adds value by noting 'provide the numeric ID or complete URL-encoded path described by the schema; use required identifiers and pagination fields exactly as documented' — reinforcing correct identifier format and emphasizing exact documentation for required/pagination fields. This is useful guidance beyond the schema alone.

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 'Get diffs between two branches or commits' — a specific verb and resource. It differentiates from siblings by explicitly contrasting with list/search tools for discovery, and its name distinguishes it from get_merge_request_diffs and related MR diff 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?

Explicitly instructs when to use this tool ('Use this for a known resource or result') versus alternatives ('choose the corresponding list or search tool when you need to discover multiple resources'). This is clear routing guidance with named alternatives.

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