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: the 100-per-call cap is explained by a browser integrity challenge the service won't bypass, and each call costs 1 credit. That's useful operational detail beyond the annotations.

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?

Three tight sentences, front-loaded with the resource definition, then the access ceiling, then cost. No filler.

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?

No output schema, and the description never characterizes the shape of returned video data (fields, ordering, pagination token). It covers the access ceiling and cost, but an agent calling this still lacks clarity on what it gets back.

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 40%; handle and filter_by are documented in the schema, but limit, sort_by, and cache_max_age are not. The description mentions VODs/highlights/uploads, which just restates the filter_by enum already in the schema, and adds nothing about limit bounds, sort behavior, or cache semantics.

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?

Clear verb-like framing of a specific resource: a channel's public VODs, highlights, or uploads. An agent can distinguish it from twitch_clip (clips) and twitch_profile, though no sibling is named explicitly.

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?

Implicit usage is clear (fetch a channel's videos), and the 100-per-call ceiling plus credit cost is stated. But there's no explicit when-to-use-vs-alternative guidance, e.g. when to reach for twitch_clip instead of video listings.

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