List Spacemail mailboxes

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

Annotations already declare readOnlyHint=true and openWorldHint=false. The description adds meaningful context beyond them: no network contact with the mail server, and that the response includes permission/capability information, which is behavioral detail the agent cannot get from the 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?

Two short, front-loaded sentences with zero filler: the first states what is returned, the second prevents a likely wrong assumption about network calls.

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 no-parameter local read tool with no output schema, the description adequately conveys both return content (connected mailboxes, allowed actions) and the key behavioral constraint (no server contact). Minor gap: it doesn't say how disabled/unconnected mailboxes appear.

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?

Zero parameters, so baseline is 4; there is nothing for the description to compensate for and it correctly doesn't waste space on parameters.

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?

Specific verb+resource: 'Shows which Spacemail mailboxes are connected' plus the permission scope of the extension. It implicitly distinguishes itself from network-facing siblings like test_connection and check_inbox by saying it doesn't contact the server, though it doesn't name an alternative explicitly.

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?

'Doesn't contact the mail server' implies a local/offline metadata check that is the right call before attempting real server operations, but the description never states when to prefer this over test_connection or list_folders. Usage is inferable rather than explicit.

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