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

Annotations already declare readOnlyHint=false, idempotentHint=false and destructiveHint=false, so safety is partly covered. The description adds genuinely useful behavioral context the annotations do not: a hard rate limit of 20 comments per hour per owner, and the server-side default that omitting author produces a stable nickname per owner.

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 compact sentences with the core action and rate limit front-loaded and no filler. The author-default clause is slightly wordy but carries real information, so no sentence is wasted.

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 mutation tool with no output schema, the essentials (required id/body, rate cap, author default) are present. However, it says nothing about what happens when the hourly limit is exceeded, required auth/permissions, or what the caller receives on success, leaving gaps for a write 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%, so id, body and author are already documented. The description only elaborates on the author default ('stays the same for the same owner'), a marginal addition, and says nothing new about id or body. 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?

The description states a specific verb and resource ('Comments on a channel'), making the write action clear and distinguishable from read/delete siblings like list_comments and delete_comment. It stops short of explicitly naming those siblings or clarifying scope, but the action itself is unambiguous.

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?

There is no guidance on when to use this tool versus alternatives such as chat_send or the comment-management siblings, and no stated prerequisites for posting. The rate limit is mentioned, but that is a constraint rather than usage guidance.

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