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

Annotations already declare idempotentHint and destructiveHint=false, yet the description adds substantial context beyond them: required authorization (PR author or repo owner, write access), the required 'repo' scope, the constraint that only open PRs are affected, and the side effect that marking ready triggers AI review. It also discloses the return shape, which no output schema provides.

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 dense sentences with the state transition front-loaded, followed by authorization, side effects, and return shape. Every clause carries signal and nothing is padded or repeated.

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?

For a mutation tool with no output schema, the description covers authorization, scope, preconditions, idempotency, side effects, and the returned fields. An agent has everything needed to call it correctly and to anticipate 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 each of the four parameters is already documented, and the description mostly restates the draft boolean semantics. The added value is limited to the behavioral constraint that the call is a no-op on non-open PRs, which is not parameter-specific. Baseline 3 is appropriate when the schema carries the semantic load.

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 ('mark a pull request ready for review') and explicitly covers both directions of the boolean toggle. It is immediately distinguishable from siblings like open_draft_pr or update_pr because it names the exact state transition it performs.

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?

Gives a clear anchor ('same rule as the web Ready for review button') and states the precondition that only an open PR changes, which tells the agent when the call will be a no-op. It does not explicitly name sibling alternatives (e.g. open_draft_pr for creating a draft), so the routing guidance is strong but not exhaustive.

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