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

Annotations already declare readOnlyHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: no login and no browser required, plus a per-result credit cost with failures free of charge. It omits rate limits and error/retry semantics, keeping it short of a 5.

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: capability and outputs first, execution/auth constraints second, cost last. No filler and the most decision-relevant information is front-loaded.

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 rich annotations and a fully documented schema, the description supplies what structured fields cannot: auth model, browser-free execution, cost per result, and a summary of returned fields in the absence of an output schema. Minor gaps remain around error handling and pagination behavior across multiple requests.

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 every parameter (kind, sort, time, limit, query, postUrl, subreddit, commentSort, maxComments, maxResults, includeComments) is already documented in the schema. The description adds no parameter-level meaning beyond implicitly naming the three modes; baseline 3 is appropriate.

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 names three concrete operations (subreddit listings, searches, single post with comments) and enumerates the return fields (title, author, body, link, created date, permalink), which is far more specific than the bare name 'reddit'. It does not explicitly differentiate itself from siblings such as serp or scrape, so it stops short of the top mark.

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 implied through the three modes, which map to the 'kind' enum, and the credit note ('1 credit per result; failed items are free') is a useful cost consideration. However, there is no explicit when-not-to-use guidance or named alternative (e.g., general web scraping or SERP tools) for an agent choosing between tools.

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