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

Annotations only cover the safety profile (readOnly, openWorld, non-destructive); the description adds the things they cannot: a 25-per-page / ~1,000-comment ceiling, a cost of $0.003 per page, and a surcharge for get_sentiment. It also enumerates the returned fields, so an agent knows exactly what it gets for the money.

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?

Front-loaded with purpose and identifier constraints, then pagination, then cost – a sensible order. It is one long semicolon-chained sentence, which is dense but not padded; a light restructure would improve scanability without cutting content.

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?

With no output schema, the description carries the return-value burden itself and does so: text, score, date, subreddit, permalink, plus the parent post title/link, along with pagination limits and pricing. An agent has everything needed to call and budget correctly.

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%, so all six parameters are already documented in the schema, and the description largely restates them (sort options, posted_ago window, page size). The billing-per-page and total-comment-ceiling notes add context, but parameter meaning is not extended beyond the schema. 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 and resource ('Get a Reddit user's comments') and scopes it by author rather than by post or subreddit, which inherently separates it from reddit_post_comments, reddit_subreddit_posts, and reddit_user_posts. The identifier forms (username or profile URL) and sort modes are named up front.

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 gives a hard operating rule ('provide exactly one' of username or url) and ties posted_ago to top/controversial, but never says when to prefer this tool over siblings such as search_reddit_comments or reddit_user_posts. Usage is implied by the resource scope rather than stated.

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