nexus_pin_comment

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

Annotations already indicate this is a write operation (readOnlyHint=false), idempotent, and non-destructive. The description adds value beyond annotations by specifying the permission requirement and the return shape (JSON with comment id or an error string). No contradiction with annotations exists.

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 short, focused sentences. It leads with the core purpose, follows with the prerequisite, and closes with the return format. Every sentence earns its place with no 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?

For a simple single-parameter mutation tool, the description is nearly complete: it names the action, the permission requirement, and the return format. It could additionally clarify what happens if the comment is already pinned, but that is a minor gap given the idempotency hint and the simplicity of the operation.

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%, and the single parameter 'comment_id' is already documented as 'Comment ID to pin.' The tool description adds no further parameter-level semantics, so the baseline of 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?

The description states a specific verb ('Pin'), a specific resource ('a comment'), and a clear destination ('to the top of its thread'). This distinguishes it from sibling tools like nexus_unpin_comment, nexus_reorder_pinned_comments, and nexus_hide_comment without needing to inspect 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 description explicitly states a key precondition: 'Requires moderator permissions or thread ownership.' This gives clear context for when the tool can be used, though it does not explicitly name alternative tools or state when not to use it. That makes it slightly below the top tier.

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