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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: the database-first then API-fallback logic, the staleness threshold (>1 week), the default fields, and the explicit 'safe, read-only' statement. It doesn't detail error cases or rate limits, but the annotations plus description cover the key behavioral traits well.

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?

The description is well-structured: it starts with the core purpose, then input format, then behavior, then exclusions, then performance options, then return summary. It is slightly dense but every sentence adds value. The 'NOT for searching' sentence is a strong disambiguator. It could be slightly shorter, but the density is justified by the tool's complexity.

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 single-comment fetch tool with rich annotations and a detailed schema, the description covers the essential context: what it returns, how it caches, when to use forceLatest, and how it differs from search. There is no output schema, but the description lists the return fields. The main gap is not describing error behavior (e.g., what happens if the comment doesn't exist), but that is a minor omission given the overall completeness.

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 57%, so the schema documents several parameters (commentId, fields, forceLatest) in detail. The description adds meaning by explaining the ID forms, the default fields, and the performance purpose of the fields parameter. It doesn't need to repeat the full field list since the schema already provides it. The description compensates for the undocumented parameters (_isTrial, _requestId, _trialToken) by not needing to explain them—they are internal/plumbing parameters.

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 ('Get'), a specific resource ('a single Reddit comment by its ID'), and explicitly distinguishes itself from the search tool ('NOT for searching - use getRedditCommentsByKeywords for keyword search'). It also clarifies the accepted ID forms, which removes ambiguity about what input is expected.

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?

The description explicitly says when to use this tool (fetch a single comment by ID) and when not to (keyword search), naming the alternative tool. It also explains the caching/fallback behavior (database first, then external API if missing or stale), which helps an agent decide whether to use this tool or force a fresh fetch.

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