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

Annotations only declare read-only/non-destructive/open-world, but the description adds real operational context: cursor batching and comma-separated cursors are rejected, author flair is unavailable from this endpoint, and completed lookups cost at least 10 Nexscope credits with repeated requests potentially re-purchasing data. These are non-obvious constraints and cost behaviors an agent could not infer from the annotations or schema.

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 core guidance is front-loaded, but the text contains duplicated content: cursor pagination, POST-for-long-cursors, and flair unavailability are each stated twice, followed by pasted marketing/pricing boilerplate ('Reddit Post Comments API View Pricing...', 'Examples are not guaranteed prices.'). Roughly half the text could be removed without losing information.

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 3-parameter read tool with no output schema, the description compensates by listing the exact response fields and documenting cost and pagination limits. What remains thin is guidance relative to sibling Reddit tools (post_detail, transcript), leaving a minor selection gap.

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?

With 67% schema coverage, the description fills the gaps: it explains that url is a Reddit post URL, that trim yields a lighter response, and—most importantly—that cursor is a single opaque value copied verbatim from more.cursor or replies.more.cursor with no batching. That meaning goes well beyond the terse schema text.

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 ('Retrieves comments and post details from a Reddit post by URL') and enumerates the returned post fields and comment fields. An agent can distinguish it from social_reddit_post_detail and social_reddit_post_transcript by the comments array it returns.

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?

Gives actionable context: use GET for normal requests, switch to POST with the same JSON body only when the opaque cursor grows too large, and pass exactly one cursor as returned by more.cursor or replies.more.cursor. It never names a sibling tool as an alternative or states when not to use this endpoint, so it stops short of a 5.

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