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

Annotations already declare readOnlyHint and openWorldHint, yet the description still adds real value: the credit cost, the time window covered (current week plus next segment), and how the result is shaped (posts of type `live`). It stops short of 5 because it says nothing about failure modes for channels with no published schedule.

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 short sentences, front-loaded with the resource and scope, then the return shape, then the credit cost. Every sentence carries information an agent needs; nothing is padded.

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 read-only, two-parameter tool with no output schema, the description covers scope, return representation and cost. The one substantive gap is `cache_max_age`, which is undocumented in both schema and description.

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% — `handle` is documented in the schema but `cache_max_age` has no description anywhere — and the description adds nothing about either parameter, not even that a twitch.tv URL is acceptable or what cache_max_age controls. It fails to compensate for the coverage gap.

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?

"A channel's published schedule for the current week, plus the next upcoming segment" is a specific resource plus scope, and the note that segments come back as posts of type `live` with `publishedAt` as start time further pins down what the tool yields. It doesn't name a sibling (e.g. twitch_userVideos for past broadcasts), so it stops short of a 5.

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: an agent can infer you call this when you want a channel's upcoming stream times. There is no explicit when-to-use/when-not-to-use guidance and no pointer to alternatives such as twitch_userVideos or twitch_profile for other channel data.

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