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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false), so 'Read-only' adds nothing. What does add value is the disclosure of behavior beyond the schema: the shape of the failure payload (failed job and step, up to 8 file:line rows linked to head sha, a 'What now?' guidance block), the `budget`/`timed_out` case that still blocks the merge, and the `{withheld, required, hint}` state plus the 'repo' scope requirement for private repos. This is meaningful operational context, though it stops short of rate limits or pagination behavior.

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 core capability is front-loaded in the opening clause and the return shape is stated compactly at the end. It is dense, with long run-on clauses and a redundant 'Read-only' sentence that repeats the annotations, but for a tool with no output schema nearly every sentence carries real payload information.

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, the description carries the burden of describing returns, and it does so explicitly ({head_sha, total_count, check_runs, required, ci}) while also covering the failure sub-payload, the withheld-logs case with its auth requirement, and the timed_out semantics. For a read-only tool of this complexity, an agent has everything needed to call it and interpret the result.

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 number are already documented, which sets the baseline at 3. The description adds only an indirect detail — that results are anchored to the PR's head sha — and gives no extra syntax or format guidance beyond the schema.

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 states a specific verb and resource with tight scope: 'List every check at a PR's current head — workflow runs, gates and commit statuses', and enumerates the returned fields. That scope implicitly separates it from single-run siblings like get_workflow_run or get_workflow_logs, but no sibling is named explicitly, so differentiation is inferred rather than stated.

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 is only implied: the mention of required-check state and the merge gate's CI verdict suggests it is the tool for judging merge readiness, and the withheld-log hint points at diagnosis. There is no explicit 'use this when…' / 'use X instead' routing, and no prerequisites section, leaving the agent to infer selection among the many CI-related siblings.

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