List Granted Mailboxes

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

Annotations already declare safe read operation. Description adds detail about scope (only granted mailboxes) and that it returns IDs, consistent with annotations. No contradictions.

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?

Two sentences, front-loaded with usage guidance, no redundant information. Every sentence is essential.

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 simple tool, rich annotations, and output schema, description provides necessary context: when to use, what it returns, and how output is used. No gaps.

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 has 100% parameter description coverage. Description does not add new meaning to parameters, only mentions the return usage. 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?

Clearly states it lists granted mailboxes and explicitly says to use it when the token can access more than one mailbox. Distinguishes from siblings by focusing on mailbox enumeration for multi-mailbox scenarios.

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?

Explicitly tells when to use ('first when the token can access more than one mailbox') and what the output is for (pass as mailbox_id). Lacks explicit when not to use, but implied.

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