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

The annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered structurally. The description adds behavior the annotations cannot convey: visibility is limited both by the API key's scope and by the org's AI channel allowlist, so results may be silently filtered. It does not discuss ordering or result size, which keeps it below 5.

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 sentences, front-loaded with what is listed and followed by the calling scenario. Every clause carries information: the org/key scoping, the channel_id workflow, and the allowlist restriction.

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 zero-parameter read-only list with an output schema available, the description covers scope, filtering behavior, and the downstream use of the returned channel_id. The only omission is any hint about what identifying fields come back besides channel_id, which the output schema presumably supplies.

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, so there is nothing for the description to disambiguate and the baseline is 4. The mention of channel_id refers to an output field used by callers, not an input, so it does not inflate or detract from this dimension.

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 (WhatsApp numbers/channels) and immediately disambiguates the domain term by equating 'channels' with 'WhatsApp numbers'. It also scopes the result set precisely ('connected to this organization', 'this key may work with'), so an agent can distinguish it from list_bots and other list_* siblings.

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?

Gives a concrete triggering scenario: call this to resolve channel_id when a send returns requires_channel on a multi-number org. That is real when-to-use guidance tied to a sibling workflow, though it names no alternative tool or explicit exclusion.

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