Reply to a comment

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

Annotations establish the write, non-idempotent, non-destructive profile, and the description adds genuinely non-derivable behavior: the reply is signed with the agent name, appears live, and reopens a resolved thread. It stops short of covering failure modes such as an unresolvable comment reference or permission errors.

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?

Five short sentences, each carrying distinct information (thread requirement, signing, side effect, mention syntax, return shape), with the routing pointer placed last as a natural closer.

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?

No output schema exists, but the description still discloses what comes back (thread replied to and who was mentioned), and the mutation's side effects are narrated, leaving no material gap for a 3-parameter tool.

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 the baseline is 3; the description goes beyond it by specifying the @Name mention convention, which the schema only calls "plain text" and would otherwise be undiscoverable.

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 ("Reply in an existing comment thread") and explicitly routes the alternative case to add_comment for new threads, so it is distinguishable from its closest sibling without opening either schema.

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?

Names list_comments as the way to locate the thread, states the condition for the alternative ("To start a new thread use add_comment"), and flags the side effect of replying to a resolved comment. Nothing about when to pick this tool is left to inference.

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