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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds genuinely new behavior: a 50-item page cap, seq ordering, cursor continuation, and the fact that reading does not mark replies as read. It adds value beyond the structured hints, though it says nothing about error or permission 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?

Three short sentences, front-loaded with the core retrieval behavior, with each sentence covering a distinct point (page size, pagination continuation, read-marking separation). Efficient, though telegraphic and slightly reliant on terms the schema does not define.

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 2-parameter tool with 0% schema description coverage and no output schema, the description omits the required postId entirely, does not explain the after cursor, and introduces a nextAfter term without saying whether it is a response field to feed back. The read-marking note is helpful but the parameter story is incomplete.

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 0%, so the description carries the full burden and falls short: it references "nextAfter" for continuation but the schema parameter is named "after", and it never mentions postId or its required 32-character hex format. The only parameter-adjacent information given uses a name that does not exist in the schema.

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 conveys the operational core ("up to 50 comments in seq order") but never states plainly that this tool retrieves the comment thread of a specific community post, nor does it differentiate itself from the sibling list_community_posts. An agent must combine the name and title to infer the actual purpose.

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 real routing guidance: continue reading when nextAfter is present, and it explicitly names acknowledge_community_replies as the separate tool for read-marking, clarifying that this call has no read-state side effect. It does not, however, say when to prefer this over list_community_posts.

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