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

Annotations already indicate read-only, idempotent, non-destructive behavior, and the description adds meaningful behavioral detail beyond that: it fetches filenames and a capped patch pack, caps the live thread, fails on private repos, pulls precedent from the index, and does not post comments. This substantially helps an agent understand side effects and limits.

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 short, front-loaded with the core purpose, and every sentence adds a distinct fact: public scope, fetched content, private-repo failure, precedent, and no comment posting. No filler or redundant restatement of the title.

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 description covers the main inputs, key limits, failure behavior, and non-mutating nature, which is sufficient for an agent to select and invoke the tool. It does not explain what 'Precedent from the index' means in detail, but the overall fetch behavior is well specified.

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%, and both parameters already have clear descriptions in the schema. The tool description does not add parameter-level details, but it does not need to because the schema fully documents url and ref.

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 this tool fetches data for a public GitHub PR: filenames, a 4000-char patch pack, a capped live thread, and precedent. It is the only PR-specific tool among the siblings, and the phrase 'Does not post comments' further distinguishes it from mutating PR actions.

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: use it for a public GitHub PR, and private repos will fail. It does not explicitly name alternative tools or when-not-to-use conditions relative to siblings, but the public-PR scope and failure mode give an agent enough context to route correctly.

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