list_ad_accounts

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

Annotations already declare readOnlyHint, giving the agent confidence it's a safe read operation. The description adds context about the return envelope structure and that it lists accounts available to the configured token. It does not contradict annotations.

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 with three short sentences covering purpose, parameters, and return value. No unnecessary words or repetition.

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?

Given the tool's simplicity, annotations, and output schema, the description is complete. It explains the use case, input parameters, and return structure (envelope with specific fields), leaving no gaps for an agent to interpret.

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 description summarizes the params argument as 'Maximum result count and JSON or Markdown response format,' which adds clarity over the raw schema. However, the schema already includes descriptions for limit and response_format, so the description's contribution is marginal.

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 tool lists Meta ad accounts and specifies its role in discovering an account ID for subsequent reads. It uses a specific verb ('list') and resource ('ad accounts'), distinguishing it from sibling tools like get_campaigns.

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 explicitly states when to use ('to discover an account ID before account-scoped reads') and when not to use ('do not use it to inspect campaigns or to create, update, or delete ad accounts'). This provides clear guidance and differentiation.

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