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

With no annotations, the description carries the behavioral burden and provides useful disclosure: the call costs 1 credit, empty results and failures are never charged, stream data is only present when the channel is live, and cache=true gives a free 24h cache hit while the default is always fresh. It does not cover auth or rate limits, but the key operational quirks are disclosed.

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 short and front-loaded with the resource and return fields. There is minor redundancy between '(1 credit)' and 'Costs 1 credit,' but otherwise each clause earns its place.

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 3-parameter tool with no output schema and no annotations, the description provides enough context to call it correctly: return fields, cost, caching behavior, failure billing, and the live-only stream field. It could explain the exact format of fields or error behavior, but nothing critical is missing.

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%, so the baseline is 3. The description adds value by specifying that cache=true is free and provides a 24h cache hit, and it reinforces the always-fresh default. It does not discuss cacheMaxAge, but the schema already fully documents that parameter.

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 identifies the resource as a Twitch channel and enumerates the specific returned data: handle, displayName, socials[], topClips, schedule preview, and stream. This helps distinguish it from sibling tools like twitch_clip or twitch_user_videos, though it lacks an explicit verb such as 'fetch' or 'get'.

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 usage context is implied: this is the tool to call for a Twitch channel profile rather than clips, schedule, or videos. However, it never names alternatives or states when not to use this tool, and 'stream only when live' reads as a data availability condition rather than a routing rule.

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