channels_follow_announcement

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

Annotations already mark readOnlyHint=false and destructiveHint=false. The description adds behavioral context by disclosing that a delivery webhook is auto-created on the target and that Discord rejects non-announcement channels. This goes beyond the annotations without contradicting them.

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?

The description is concise, well-structured with clear labels (Purpose, When to use, When NOT to use, Returns), and avoids any redundant filler. Every sentence adds information.

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 annotations covering key behavioral flags, the description sufficiently covers purpose, usage conditions, return value, and a critical constraint. It could mention permissions or rate limits, but these are not essential given the existing structured data.

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 100% and each parameter already has a meaningful description (channel_id as source, webhook_channel_id as target, audit_reason as audit log reason). The tool description does not add further parameter-level detail beyond what the schema provides, so baseline 3 is appropriate.

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?

The description states 'Cross-post messages from an announcement (news) channel into a target channel via a webhook,' which uses a specific verb, resource, and mechanism. This clearly distinguishes it from sibling tools like messages_crosspost or webhooks_create.

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 description includes explicit 'When to use' and 'When NOT to use' sections, with a concrete use case (mirroring release announcements) and a rejection condition (source not type 5). It does not explicitly name alternative tools, so it misses the full 5 criterion, but the guidance is clear and actionable.

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