Get pull request diff

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

The annotation readOnlyHint: true already indicates this is a safe read operation, so the description does not need to repeat that. The description adds no extra behavioral details (e.g., truncation via max_chars), but it does not contradict the annotation. This is acceptable given the annotation coverage.

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 core purpose. Every word earns its place, with no filler or redundancy. This is an example of ideal conciseness.

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?

Given the simple nature of the tool, the annotations cover safety, and the schema fully documents parameters, the description is sufficient. The return format is implied (the diff), and no output schema exists, so a more detailed description could help but is not critical for this straightforward operation.

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?

Input schema description coverage is 100%, so all parameters (pull_request_id, max_chars, repo_slug, workspace) are already well-documented. The description adds no additional parameter meaning beyond what the schema provides, which meets the baseline for full schema coverage.

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 with a specific verb ('Fetch') and resource ('the unified diff for a pull request'). This distinguishes it from sibling tools like get_diffstat (statistics) and get_pull_request (metadata), making the purpose immediately clear.

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 provides clear context for when to use the tool: to fetch the unified diff of a pull request. It does not explicitly mention alternatives or exclusions, but the purpose is unambiguous. A 4 is appropriate because it lacks explicit when-not-to-use guidance, but the context is clear.

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