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

Annotations already declare readOnlyHint: true and openWorldHint: true, so the description doesn't need to repeat read-only status. It adds useful behavioral context by mentioning 'Returns a list (use cursor when paginated)', which informs the agent about the return type and pagination method. This is beyond what annotations provide, though it doesn't describe other behaviors like output fields or rate limits.

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 description is two concise sentences that front-load the primary purpose ('List videos from a Twitch channel by handle') and then add the important pagination note. Every word earns its place; no fluff or redundant details.

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 simple list tool with 3 parameters (1 required), annotations covering read-only and open-world, and full schema coverage, the description is adequate. It states purpose and pagination. While it doesn't specify return fields, the absence of an output schema and the openWorldHint imply flexibility. The main gap is lack of usage guidance, but that's covered under its own dimension. Overall, it's sufficient for an agent to call this correctly.

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 description coverage is 100%, and the schema already documents all three parameters thoroughly: handle (with or without @), sortBy (enum with meaning inferred), and filterBy (with detailed explanation of values). The description adds no additional parameter semantics beyond what the schema provides, which aligns with the baseline for high coverage.

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 states the specific verb 'List', the resource 'videos from a Twitch channel by handle', making it clear what the tool does. It distinguishes from siblings like twitch_clip_get (gets a specific clip) and twitch_profile_get (gets profile), and the handle clarifies it's channel-based. The title aligns with the description.

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?

The description provides no explicit guidance on when to use this tool versus alternatives. It doesn't mention alternatives like twitch_clip_get or other profile video tools. The only hint is the 'by handle' scope, which implies usage for channel videos, but no direct comparison or exclusion is given.

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