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

No annotations are provided, so the description carries the full behavioral burden. It discloses credit costs, free caching semantics, no-charge on empty/failed results, opaque cursor behavior, and state echo. It does not mention auth requirements or error shape, but the important operational behaviors are covered.

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 tightly packed and front-loaded: the action and resource come first, followed by return hints, cost, and caching. Every sentence earns its place and there is no redundant restatement of schema fields.

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 no output schema and no annotations, the description communicates the essential return fields, pagination cursor behavior, cost model, and cache behavior. It could be more explicit about response envelope or error handling, but the information needed to invoke it correctly is present.

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%, setting the baseline at 3. The description adds value beyond the schema by clarifying that the cursor is an opaque GitHub Link token, that state is echoed as data.state, that cache=true yields a free 24h hit, and that billing is per result.

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?

Description opens with a specific verb and resource: "List repo PRs", and enumerates the key returned fields (draft, labels, author{}, head/base, cursor). This clearly distinguishes it from sibling GitHub tools like github_activity or github_repositories, which target different resource types.

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 implies usage context: call it when you need pull requests for a repository, with cache and state options detailed. It does not explicitly name alternatives or say when not to use it, so guidance is adequate but leaves routing to inference.

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