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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered by structured data. The description adds nothing beyond that: no note on what happens when the ID does not exist, nor any visibility/permission scoping for comments. For a lookup tool with full annotation coverage this is a minimal but not contradictory entry.

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?

One short sentence, front-loaded with the verb and resource, with zero wasted wording. It is appropriately sized for a trivial single-record lookup, though it stops short of carrying any extra signal.

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?

An output schema exists, so return values need no explanation, annotations cover safety, and the sole parameter is fully documented in the schema. The only meaningful gap for a fetch-by-ID tool is error behavior on missing or inaccessible IDs, which is minor.

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% and the single parameter carries its own description ('The ID of the comment to retrieve'). The description's phrase 'by its ID' merely reiterates the schema, adding no format, source, or range detail, so the baseline 3 applies.

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 (get) and resource (a single comment) plus the lookup key (ID), which implicitly distinguishes it from list_comments. It does not explicitly name any sibling, so differentiation rests on inference from the singular 'a single comment'.

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?

Usage is only implied: retrieve one comment when you already have its ID. There is no explicit statement of when to prefer this over list_comments or search, and no exclusions or prerequisites are given.

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