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

Annotations declare readOnlyHint=false, destructiveHint=false, and idempotentHint=false, indicating a mutating, non-idempotent operation. The description adds critical behavioral context: it explains the no-op behavior for reply ids and notes the 'image comments feature' requirement. It does not state the response format, but that is covered by the output schema, so this is strong.

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 sentences, each earning its place: the action, the critical id constraint, and the permission/feature precondition. Front-loaded with the core purpose, then the key caveat.

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?

With an output schema present and annotations covering the safety profile, the description covers all necessary operational details: the id source, the no-op case, permissions, and feature requirement. Nothing essential is missing for an agent to invoke it correctly.

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 schema already explains both parameters: commentId as thread root and resolved as boolean. The description reinforces this by repeating the root-id requirement and the meaning of true/false, but it adds no new syntactic or type details beyond the schema. Baseline 3 is appropriate.

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 comment thread resolved or reopen it.' It clearly describes the two possible actions and explicitly differentiates from siblings by noting that the id comes from list_comments and that resolving affects the root thread. This makes it distinguishable from update_comment and delete_comment.

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?

Provides explicit guidance on when to use: it tells the agent to get the id from list_comments, warns that resolving stamps the thread ROOT so a reply id is a no-op, and mentions that any team writer may toggle this. It also implies when not to use (e.g., if you need to edit text, use update_comment) by specifying the exact action.

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