get_pr_diff

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

With readOnlyHint and destructiveHint already in annotations, the description adds valuable behavioral detail: the result is capped at max_bytes, and bytes_total always reflects the full patch so truncation is detectable. This goes beyond the annotation safety signals without contradicting them.

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 first two sentences are concise and front-loaded with the core behavior and truncation caveat. However, 'See #314' is a cryptic reference that adds little for an AI agent, and the description could either elaborate or drop it.

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 output schema presumably documents return fields, and annotations cover safety, so the core fetch behavior is adequately captured. The main gaps are missing when-to-use guidance relative to closely related tool names and the opaque '#314' reference.

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 only 25% and the description adds little to parameter meaning: it only repeats that max_bytes caps the patch, while the schema already says that. repo_owner, repo_name, and pr_number are never explained, though their purpose is inferable from the tool name.

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 uses a specific verb ('Fetches') and names the exact resource ('the diff/patch of a specific pull request'), then adds the max_bytes cap as a distinguishing behavior. This clearly separates it from sibling tools like get_pr_content and get_pr_status_checks.

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 guidance is given about when to choose this tool over alternatives (e.g., get_pr_content) or when not to use it. The only contextual phrase is 'specific pull request', which does not establish selection criteria.

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