list_allowed_recipients

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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds useful operational context beyond annotations by stating that an empty list indicates unrestricted access, which is valuable for interpreting results.

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 a single concise sentence, front-loaded with the action verb 'List,' and contains no filler or redundant information. Every word adds value.

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?

This is a simple tool with no parameters and an output schema, so the description need not explain return structures. It covers the essential behavior (listing the allowlist) and the edge case (empty when unrestricted), making it fully complete for an agent's decision-making.

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 tool has zero parameters, so the description has nothing to add regarding parameter syntax or meaning. The schema coverage is 100% (none present), and the baseline for zero parameters is 4, which the description meets.

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 uses the specific verb 'List' and names the exact resource, 'configured recipient allowlist,' clearly distinguishing it from the sibling list_allowed_senders. It also states the allowlist's relevance to send_email and save_to_mailbox, making the tool's purpose 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?

The description provides clear context by explaining what the allowlist controls (which addresses send_email can send to and save_to_mailbox can address) and notes the unrestricted empty-list case. It does not explicitly name alternative tools or exclusions, but the context is sufficient for a simple read-only tool.

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