whatsapp_get_newsletter_by_invite

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description goes beyond them by confirming the non-subscribing behavior ('without following it') and by disclosing the return payload (channel info and JID) in the absence of an output schema.

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 action and scope, then the side-effect disclaimer, then the return value. Nothing is wasted and no sentence is redundant.

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 one-parameter read tool with no output schema, the description covers the action, the non-following constraint, and the returned fields — enough to invoke it correctly. It stops short of naming the sibling lookup tool an agent might confuse it with.

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?

With 100% schema description coverage and a single parameter, the schema already defines 'code' as the newsletter invite code. The description repeats the invite-code concept but adds no format, length, or validation detail beyond the schema, so baseline 3 applies.

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 (look up) and resource (channel/newsletter) keyed on an invite code, which separates it from whatsapp_get_newsletter (JID-based) and whatsapp_list_newsletters. The only wrinkle is calling it a 'channel' while the tool name says newsletter, but the intent is unambiguous.

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?

'Without following it' implies the reconnaissance use case (preview before subscribing, per whatsapp_set_newsletter_subscription), which is genuine guidance. However, it never names the alternative lookup tool or states when to prefer this over whatsapp_get_newsletter, so the routing is left implicit.

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