AgentMail

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

With no annotations provided, the description carries full burden but only states the basic operation. It doesn't disclose whether this is a read-only operation, what permissions are required, whether it returns full message content or metadata, error conditions, or rate limits. 'Get' implies retrieval but lacks behavioral details needed for safe invocation.

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 extremely concise at just three words, front-loading the core purpose with zero wasted text. Every word earns its place, though this conciseness comes at the expense of completeness.

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 2-parameter tool with no annotations, 0% schema coverage, and no output schema, the description is inadequate. It doesn't explain what constitutes a valid message ID, how inboxes relate to messages, what data is returned, or error scenarios. The minimal description leaves too many gaps for reliable tool invocation.

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?

With 0% schema description coverage for both parameters, the description provides no parameter information beyond what's implied by the tool name. It doesn't explain what 'inbox_id' and 'message_id' represent, their format, or how they relate to each other. The description fails to compensate for the complete lack of schema documentation.

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 'Get message by ID' clearly states the verb 'Get' and resource 'message', but it's vague about scope and doesn't differentiate from sibling tools like 'getThread' or 'listMessages'. It specifies retrieval by ID but lacks context about what a 'message' represents in this system.

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?

No guidance is provided about when to use this tool versus alternatives like 'getThread' (for thread-level messages) or 'listMessages' (for multiple messages). The description implies it's for retrieving a single message by ID, but doesn't mention prerequisites like needing an inbox_id or when this is the appropriate retrieval method.

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