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

Beyond readOnly/openWorld annotations, the description discloses result size (~25 items), included fields, a key data limitation (no scores or comment counts), and precise pricing behavior: $0.002 per successful call via x402, with failed calls not charged. This is substantive behavioral context.

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?

Two tightly written sentences with no filler. Scope and limitations are front-loaded, followed by essential pricing and payment details, all of which earn their place.

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?

Given the simple two-parameter schema, existing output schema, and annotations, the description is complete for correct invocation: it covers scope, sort behavior, approximate result size, field set, data limitations, and payment terms.

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%, and the schema already documents both parameters, including the sort values and default. The description restates the sort options but adds no extra parameter-level semantics beyond the schema, so 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 states a specific resource and scope: posts from one subreddit's public feed, with sort options and returned fields. It clearly conveys what the tool returns, but it does not explicitly name sibling tools such as social_reddit_posts_comments or social_reddit_profiles to sharpen differentiation.

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 by 'Posts of one subreddit' and the sort options, and the description usefully notes that the feed lacks scores/comment counts so vote-ranking is impossible. However, it does not explicitly say when to choose this over sibling tools like comments or profile endpoints.

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