mailkite_list_messages

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

The description goes well beyond the readOnlyHint annotation by disclosing the bare-array response shape, newest-first ordering, the pagination contract (pass the last received_at as the next before), and the auth requirement. There is no contradiction with 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?

Every sentence earns its place, with the main purpose front-loaded and filtering, pagination, default behavior, and auth kept compact. Backticks unambiguously highlight parameter names.

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 list tool with no output schema, the description covers default behavior, filtering, cursor pagination, response type, and authentication in one place. Nothing essential for a first correct call is missing.

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 richly documents search, before, and limit with precise meanings: field matching, received_at cursor, pagination size, and default behavior. However, the input schema declares zero properties and disallows additional properties, so the documented parameters are not represented in the machine-readable schema—an inconsistency that prevents a 5.

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 action and resource: 'List stored messages, newest first.' This is specific and more informative than a bare tool name. However, it does not explicitly contrast itself with close siblings like mailkite_list_mailbox_messages or mailkite_get_message, so it stops short of a 5.

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 gives concrete usage context: optional search semantics, pagination via before/limit, the default of newest 100, and the required management session token. It does not mention alternatives or say when to prefer this tool over sibling list/get tools, preventing a higher score.

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