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

The description discloses important side effects beyond the annotations: the comment stays open, the reviewer will see the reply on the same thread, responses may be delayed, closed comments stop accepting replies, and mentioning someone emails them. It also clearly states agents cannot be mentioned, which is non-obvious 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 description is long but dense: the main purpose and sibling distinction are front-loaded, followed by workflow and behavioral caveats. Every sentence contributes useful guidance, though some points are repeated from the input schema and the single-flow structure could be tighter.

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 tool with no output schema, the description gives agents a complete mental model: how to reply, how to read the reviewer's response, whether to wait, which comments are eligible, and how mentionUserIds changes behavior. It also names the sibling tools explicitly, so context switching is clear.

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?

The schema already documents all parameters at 100% coverage, including message behavior and mentionUserIds. The description adds practical value on top—such as when to bring in a person, that IDs must come from mentionablePeople, and that each mention triggers an email—but the additional nuance is somewhat redundant with the parameter descriptions.

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 concrete action—reply to one review comment—and immediately adds the key differentiator of leaving the comment open. It also explicitly contrasts with review-resolve, so the agent can distinguish it from the closest sibling.

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 explicitly says to prefer this tool over review-resolve whenever the exchange is not finished, and explains that resolving closes the thread. It also gives eligibility guidance, such as replying only to comments addressed to you or marked unassigned, and clarifies the mention flow for pulling in humans.

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