Manage channels

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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false and destructiveHint=false, so the safety profile is covered. The description adds real behavior beyond that: it distinguishes the follow/unfollow/mute/unmute state changes, notes create returns the channel, clarifies react removes a reaction with an empty string, and explains that mark_viewed merely counts the account as a viewer. Auth requirements are only implied through the schema's accountId note.

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?

Front-loads the resource definition and the sibling hand-off before the action list, and every bullet carries information rather than repeating the enum names verbatim. It is long, but the length is justified by eleven distinct actions; only marginally more verbose than necessary.

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 13-parameter, multi-action tool with no output schema, the description covers each action's semantics and gives partial return shape for get, list_messages and create (fields, ordering, counts). It stops short of describing list pagination behavior or return shapes for the remaining actions, which is the main remaining gap.

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 schema already documents every parameter including per-action requirements, pagination and the idempotency contract; baseline 3 applies. The description contributes only a little extra meaning, chiefly the `...@newsletter` id format and the `to`-field routing for posting.

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?

Opens with a precise definition of the resource (WhatsApp one-to-many broadcast channels, ids ending in @newsletter) and enumerates every supported action with a verb-plus-resource phrasing. It also draws a sharp boundary against the sibling send_text/send_media tools for posting, so an agent can tell it apart without opening any schema.

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?

Explicitly routes the one ambiguous case to alternatives: 'To post to a channel the account administers, use send_text or send_media with `to` set to the channel id.' Each action bullet states its precondition or scope (e.g. preview_invite 'without following it'), leaving little to inference.

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