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

With no annotations, the description carries the burden itself and does disclose two real traits: an auth requirement (memory:read) and the degraded-result shape when the installation token can't read check runs. However it leans on 'Same binding errors as github_repo_get' as a cross-reference, and never states the read-only nature, rate limits, or whether statuses and conclusions are both returned.

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?

Three short sentences, front-loaded with the core purpose and followed by the operational caveats. Minor cost is the cryptic 'Same binding errors as github_repo_get' clause, which is compact but opaque out of context.

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?

An output schema exists, so return-value explanation isn't needed, and the auth/error context is useful. But for a tool whose error semantics are explicitly referenced via another tool's description, the definition leaves the agent to look elsewhere for that behavior.

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 'github' (owner/repo) and 'number' (PR number) are already fully documented. The description adds no format hints or constraints beyond that, so the 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+resource+scope: check-run status for a single pull request's head commit. That is clearly distinct from github_pr_get (PR metadata) and github_pr_list, which an agent can infer without opening the schema. It stops short of naming a sibling alternative outright, keeping it at 4 rather than 5.

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 on when to call this versus github_pr_get or github_repo_get — the agent must guess that 'I need CI results for PR N' maps here. The only conditional language is a failure mode ('unavailable=forbidden when the installation token cannot read check runs'), which is availability information rather than usage direction.

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