reply_to_review_comment

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

Annotations already indicate this is a mutating, non-idempotent, non-destructive operation. The description adds the behavioral nuance that it attaches to an existing thread rather than creating a new one, which is useful but not extensive. It does not mention response behavior or side effects beyond the reply itself.

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 a single, front-loaded sentence with no filler. Every word contributes to explaining the tool's purpose and its key distinction from starting a new thread.

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?

The description is adequate for a relatively simple write operation combined with annotations and an output schema, but it leaves usage guidance thin and relies on self-explanatory parameter names. For a 5-parameter required call, more context about when to reply and how reply threading works would improve completeness.

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 only 20%, so the description should compensate for undocumented parameters. It does not: body, pr_number, repo_name, and repo_owner receive no additional explanation. The comment_id parameter already has a schema description, and the tool description mostly reinforces that existing meaning.

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 uses a clear verb ('Replies') and a specific resource ('existing review thread'), and explicitly distinguishes this tool from starting a new thread. This is enough to separate it from sibling comment-adding tools without opening their 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?

The phrase 'rather than starting a new one' provides clear usage context: use this tool when replying to an existing review thread, not when creating a new comment thread. It does not name a specific sibling alternative, but the exclusion is explicit enough.

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