mail_get_message_headers

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

Annotations already indicate idempotency and read-only nature. The description adds that the output is the 'raw header block', but lacks details on what this includes (e.g., all headers? only certain ones?) or performance considerations.

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 (one sentence), but it is too minimal; a bit more detail (e.g., that it returns headers without body) could improve understanding without adding verbosity.

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 the tool's simplicity and lack of output schema, the description is insufficient. It does not explain what 'raw header block' means, how to choose between messageId and rfc822MessageId, or any edge cases.

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 coverage is 50% (two of four parameters have descriptions). The tool description does not add any extra meaning to the parameters, so it fails to compensate for the missing descriptions on accountName and mailboxPath.

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 tool gets the 'raw header block' of a message, which is specific and distinct from siblings like mail_get_message (full message) or mail_get_message_source (raw MIME source).

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 on when to use this tool vs alternatives. For instance, when to use messageId vs rfc822MessageId, or why one might prefer headers over the full message, is not addressed.

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