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

No annotations are provided, so the description must carry the full behavioral disclosure. It mentions the 'active' filter and account scoping, but does not disclose pagination, ordering, result limits, or error conditions. For a list operation, this is a notable gap since the agent cannot predict if all agents are returned at once or if further calls are needed.

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?

A single, front-loaded sentence with no fluff. It states the action, resource, and scope immediately. Every word 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?

For a simple list tool with one optional parameter and no output schema, the description sufficiently explains what is returned (active agent profiles) and the account scoping. It lacks details on return format or pagination, but given the low complexity and that the parameter is fully described, the description is almost complete. The missing behavioral details slightly reduce completeness.

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 only parameter (accountId) has 100% schema description coverage ('Optional account ID (automatically scoped).'). The description adds no extra meaning to the parameter, so the schema already handles it. Baseline 3 applies because the schema fully documents the parameter.

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 clearly states the verb 'Retrieve' and the resource 'active messaging agent profiles (RCS and WhatsApp)'. It distinguishes this from siblings like list_campaigns, list_templates, and get_agent_profile by specifying it lists agents rather than campaigns/templates and returns a collection rather than a single profile.

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 implies usage for listing agents, but it does not explicitly contrast with get_agent_profile for fetching a single agent. The context signals include siblings, but the description itself gives no explicit 'use this when...' or 'instead of...' guidance. The usage is reasonably clear from the resource name, but not formally stated.

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