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

Annotations only carry destructiveHint=true, so the description adds useful context: content permits basic HTML and the underlying endpoint is POST /api/comments. It does not disclose permission requirements, whether the comment can later be edited or removed, or what the call returns. With annotations covering the mutation flag, this is adequate but not rich.

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?

Two short sentences, no filler, with the core action front-loaded and the read alternative and richer content note following. Every clause carries information an agent can act on.

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 two-parameter write tool with no output schema and minimal annotations, the description covers action, content format, sibling route for reading, and endpoint. The main remaining gap is the response shape (e.g. the created comment id), which would help since no output schema exists.

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 coverage is 100%, so the baseline is 3, but the description adds a genuinely useful constraint for the content parameter: it may contain basic HTML. That is format information absent from the schema, which specifies only minLength 1 and type string.

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 (add) plus resource and scope (a comment to a task's discussion thread). It is immediately distinguishable from siblings like paymo_create_task or paymo_update_task, which operate on the task itself rather than its thread.

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 a clear when-to-use and routes the agent to paymo_get_task with include=thread.comments for the read-side counterpart. It does not state exclusions or prerequisites (e.g. permissions, whether the task must be open), so it stops just short of explicit when-not guidance.

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