List open pull requests

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

Annotations already declare readOnlyHint and idempotentHint, so safety is covered. The description adds genuinely non-obvious behavior: the precedence rule (failure > pending > success), the empty-check-set = "unknown" edge case, and the pagination limitation. Only the return shape per PR is left unstated, which the output schema covers.

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?

Four short sentences, front-loaded with the action before the aggregation rules. The final sentence mildly duplicates the limit parameter's schema note, keeping it just short of full marks.

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 an output schema present, return structure need not be explained, and the description covers the ambiguous parts of the output (CI rollup precedence, unknown state) plus the pagination boundary. A note on sort order or what happens beyond the first page would make it complete.

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%, so owner, repo, and limit are already documented at the field level. The description adds only the repository-scoping framing and repeats the first-page constraint already present in the limit description; baseline 3 applies.

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?

States a specific verb and resource ("List open pull requests") plus the scope constraint ("for one repository") and an additional computed dimension (CI rollup). An agent can distinguish this from list_issues or summarize_pull_request without inspecting schemas.

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?

Usage context is implied by "for one repository" and "first page only," which tell the agent this is a single-repo, non-paginating listing. However, it never names an alternative or states when not to use it — e.g., that summarize_pull_request is the right tool for a single PR's detail.

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