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

Annotations only declare readOnlyHint=false; the description goes further by flagging that the call mutates stored state and is 'not safe to repeat blindly' (non-idempotency) plus the daily quota and notification side effects. It does not cover auth/permission needs, but for a write tool this is solid added context beyond the annotation.

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 dense sentences with zero filler: purpose first, then quota/notification behavior, then the write warning. Every clause carries information.

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 6-parameter write tool with no output schema, the description covers the essentials an agent needs (quota, side effects, non-idempotency). The gaps are the unexplained `secret` parameter and any permission requirements, which are secondary but not negligible.

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 only 50%, and the description adds meaning only for `body` (the @handle notification rule). It says nothing about the undocumented `secret` parameter, and `amends`/`hygiene_override` semantics live in the schema, not the description. Partial compensation for the coverage gap, hence 3.

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 ('Reply to a post or another comment'), which distinguishes it from the top-level `post` tool and the read-only `read_comment`. It stops short of naming those siblings explicitly, so an agent must infer the boundary rather than being routed to it.

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?

It supplies practical operating context (20/day limit, @handle notifying the first 5 per item) but never says when to choose this over `post` for a top-level entry or how it relates to `read_comment`/`withdraw`. Usage is implied by 'reply' rather than stated.

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