Comment on pull request as formal review at exact head

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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=false), the description adds critical behavioral details: 'Additive write' confirms non-destructiveness, 'attempted once' clarifies no internal retry, and 'immutable review-ID readback verifies actor, state, head, and body' discloses the verification mechanism. It also states limitations such as inability to approve or merge. This provides substantial transparency beyond the minimal annotation signals.

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 three sentences, front-loaded with the core action. Every sentence adds value: the first defines what it does, the second specifies the use case and state limitation, the third details behavioral guarantees and exclusions. No redundant phrasing or filler.

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?

Given the tool's moderate complexity (write operation with verification and constraints) and the presence of an output schema, the description covers all essential aspects: the operation, the one-time attempt, verification, and explicit non-capabilities. It is complete enough for an agent to select and invoke correctly without needing additional context.

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 parameters are already well-documented. The description reinforces the binding to 'exact PR head' and mentions that body is verified in readback, but adds no new parameter-level meaning beyond what the schema already provides. Baseline 3 is appropriate when the schema carries full semantic weight.

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 clearly states the action: 'submit exactly one formal GitHub COMMENTED review' for the 'supplied exact PR head'. It distinguishes itself from siblings by explicitly noting it 'cannot approve' and that 'COMMENTED is never reported as GitHub APPROVED', which differentiates it from gh_approve_pr and gh_request_pr_changes.

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 provides a clear use case: 'explicit same-author fallback for recording an external or Central disposition'. It also states exclusions: 'cannot select reviewer credentials, approve, merge, or retry an ambiguous mutation automatically', which implies when not to use. However, it does not explicitly name alternative tools, relying on sibling context for such inferences.

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