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

The annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered, but the description still adds the return shape and paging semantics. The cost disclosure is behaviorally relevant (each completed lookup consumes credits and repeated requests may re-purchase the same data), but it is muddled: 'at least 10 Nexscope credits' is followed by '1 credit per request', so the agent cannot compute the real cost.

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 first three sentences are useful and front-loaded, but the rest is scraped pricing boilerplate: 'View Pricing', 'Get comments from a Snapchat Spotlight URL', a second per-request price that contradicts the first, and a disclaimer about supplier units. This repetition and internal inconsistency dilute an otherwise short definition.

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 two-parameter read tool with no output schema, the description covers what is fetched, what comes back, how to paginate, and that calls are metered, which is enough to call it correctly. The remaining gaps are minor: no URL format example and no failure or rate-limit behavior.

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 already 100%, so the baseline is 3. The description adds real meaning on top: it explains that the cursor comes from the previous response and is fed back in to page further, which the schema's one-line 'Pagination cursor from the previous response' only partly conveys.

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 gives a specific verb and resource: fetch public comments from Snapchat Spotlight by URL, and it names the returned entities (snap id, comments, cursor, hasMore). It never explicitly distinguishes itself from the sibling social_snapchat_spotlight or social_snapchat_profile, but the resource and lookup key are unambiguous.

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 rather than stated: the description says to pass the returned cursor back to load more comments, which is genuine pagination guidance. It gives no when-to-use/when-not-to-use guidance against the sibling Spotlight and profile tools, and no prerequisites for what a valid Spotlight URL looks like.

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