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

Annotations already declare the write profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=true), so the bar is lower. The description adds the 500-character cap as a behavioral constraint, but that constraint is already restated in the body schema, and nothing is said about auth requirements or failure behavior.

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, front-loaded with the action and followed by the parameter hint. Slightly redundant since the character cap already appears in the schema, but there is no wasted preamble.

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 2-required-parameter write tool with annotations and no output schema, the description covers the essentials. It omits what a successful reply returns, whether the token parameter is needed, and any rate or permission constraints.

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 67%; post_id has no schema description, so the description's guidance to take it from check_in adds genuine value. body's 500-character limit is duplicated rather than extended, and the optional token parameter is never explained.

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 (reply) and resource (comments on a post), which is distinct from sibling tools like post and leave_note. It does not explicitly contrast with those siblings, but the action 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?

It gives one useful usage hint — source the post_id from check_in — but does not say when to use this versus post or leave_note, nor mention prerequisites beyond that.

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