youtube list my channels

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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds genuinely new behavioral context beyond them: the operation costs 1 quota unit, which matters for a quota-constrained YouTube API. It does not discuss pagination or result limits, but the zero-parameter shape makes those largely moot.

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 short sentences with zero filler, and the substantive scope constraint is front-loaded before the cost note. Every 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?

With an output schema present and rich annotations, the definition needs only to say what is listed and any cost caveat, both of which it does. A note on whether results include channel IDs or whether unauthenticated calls fail would close the remaining gap, but nothing essential 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?

The tool takes zero parameters and the schema is trivially complete, so there is nothing for the description to compensate for. Baseline 4 applies; no parameter claims are made or needed.

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?

States a specific verb (List) and resource (YouTube channels) plus the scope qualifier 'owned by the signed-in user', which separates it from public-facing siblings like youtube_search and from youtube_list_my_playlists. It never names a sibling explicitly, so the differentiation is inferred rather than stated.

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 phrase 'owned by the signed-in user' implies the when-to-use context (fetching your own channel identity rather than searching public content), but there is no explicit guidance on when not to use it or which sibling to pick instead. An agent must infer the boundary from the scope phrase alone.

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