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

Annotations already declare readOnlyHint and openWorldHint, so the bar is lower, yet the description adds real context beyond them: results are limited to public comments, ordering is Snapchat's ranking and not caller-controlled, and each call costs 1 credit. It stops short of stating rate limits or whether the ranking can drift between pages, which keeps it at 4 rather than 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?

Four short sentences, front-loaded with what the tool returns and followed by pagination and cost. The opening sentence largely restates the title, which is minor waste, but every other sentence carries distinct 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?

With no output schema, the description usefully characterizes the return payload (comments, reaction counts, threaded-reply counts) and the pagination contract, plus cost. Missing only minor operational detail such as approximate page size, which is a small gap for a 3-parameter read tool.

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 67%: url and cursor are already documented in the schema, and the description's note about cursor only echoes the schema text. cache_max_age is undocumented in both places, and the description adds no format or freshness semantics beyond what the schema provides. 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?

States a specific verb+resource: fetching public comments on a Snapchat Spotlight by URL, and adds distinguishing detail (ranked by Snapchat, includes reactions and threaded-reply counts). It is distinguishable from snapchat_spotlight, but it never names that sibling or explicitly says it returns comments rather than the Spotlight post itself, so the differentiation is implied rather than stated.

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 paging guidance ("Pass the `cursor` from the previous response to page") which is genuinely useful usage context for a paginated call. However, there is no guidance on when to choose this over snapchat_spotlight or snapchat_profile, and no prerequisites or exclusions are stated.

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