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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the bar is lower. The description still adds two non-obvious facts: no credential is required, and a comment belonging to another listing returns 404 indistinguishable from an unknown ID. It says nothing about the response shape or rate limits.

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 purpose, then the use case, then the access and scoping caveat. Nothing is repeated from the annotations and no sentence is filler.

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 read tool with no output schema, the description covers purpose, access, the reply_to use case and the cross-listing failure mode. The return payload is unexplained, but there is no output schema requiring it and the failure semantics are the part an agent most needs.

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 both IDs are already documented and the baseline is 3. The description adds meaning beyond the schema by tying the two parameters together: the comment must belong to the given listing or the call fails as if the comment did not exist.

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 and resource ('Read one public question or answer') and pins the scope to a single comment on a single listing, which is exactly what the name get_comment implies. It does not name a sibling such as read_discussion for thread-level reading, so differentiation is implicit rather than explicit.

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?

Gives a concrete trigger: use it to resolve the comment that a reply's `reply_to` names, which is a real, actionable when-to-use cue. It stops short of stating when not to use it or which sibling handles reading a whole discussion.

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