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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description still adds real value beyond them: 'Public metadata' signals no authentication is required, and 'Costs 1 credit' discloses a billing cost that appears nowhere in the structured fields — a material detail for an agent deciding whether to call.

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 tight sentences, front-loaded with purpose then the returned fields, with the credit cost last. The leading fragment 'Clip details.' largely restates the title and could be folded into the following sentence, but nothing else is wasted.

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 field enumeration (views, duration, creator, broadcaster, category, VOD offset) is exactly the return-value disclosure an agent needs, and the credit cost is covered. Remaining gaps are minor: no guidance on invalid/private clip handling and no explanation of the undocumented caching parameter.

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 50%: the required `url` parameter is thoroughly documented in the schema (two URL forms plus bare slug), but `cache_max_age` has no description anywhere. The description adds nothing about either parameter, so it neither compensates for the undocumented caching parameter nor explains cache/refresh behavior.

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?

Names the resource (a single Twitch clip) and enumerates exactly what metadata is returned (views, duration, creator, broadcaster, category, VOD offset), so an agent knows this is a single-item metadata lookup rather than a listing. It never names the sibling it is not (twitch_userVideos, kick_clip), so differentiation is inferred from the resource name alone.

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 only implied: you have a clip URL/slug, so you call this. There is no explicit statement of when to prefer it over twitch_userVideos, twitch_profile, or the parallel kick_clip tool, and no mention of preconditions or failure cases such as private or deleted clips.

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