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

Annotations already declare readOnlyHint and openWorldHint, so the description does not need to re-establish safety. It adds value the annotations cannot: a stated cost of 1 credit, the fact that only public Spotlights work, and that the transcript is only present 'when Snapchat has one' – a meaningful conditional an agent should plan around.

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 sentences, front-loaded with the resource identity before the field inventory. The field list is dense but each item is a distinct return value, and the credit cost is placed at the end where it reads as a note rather than burying the lede.

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?

There is no output schema, and the description carries that burden well by enumerating exactly which fields come back and flagging the transcript's conditional presence. The only gap is the unexplained cache_max_age parameter, which is minor relative to the return-value coverage.

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 only 50%: url is documented in the schema and the description reinforces it with 'by link', but cache_max_age is undocumented in both places, leaving an agent to guess its format and effect. With half the parameters undescribed, the description should have compensated and does not.

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 the resource precisely ('A public Snapchat Spotlight video') and enumerates what the tool returns: view/like/comment/share counts, caption, hashtags, duration, creator, thumbnail, media URL, and transcript. It is clearly distinguishable from snapchat_profile, though it does not explicitly contrast with the sibling snapchat_spotlightComments, which is the closest lookalike.

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?

'by link' implies a URL-keyed lookup, which is the main usage signal, but there is no explicit when-to-use guidance, no mention of when to prefer snapchat_spotlightComments for comment data, and no stated fallback. Usage is inferable rather than stated.

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