read_message

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

No annotations are provided, so the description carries the full burden. It correctly indicates a read-only operation and specifies the return format (headers + decoded body). However, it does not disclose other behavioral traits such as error handling, prerequisites, or rate limits, though for a simple read tool this is acceptable.

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 a single, well-structured sentence front-loaded with the action and key details. No extraneous information, every word adds value.

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 the presence of sibling tools like search_mail and list_attachments, the description is sufficiently complete. It covers the main purpose, input linking, and output, though it does not mention optional parameters or error conditions.

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 description coverage is 0%, so the description must compensate. It clarifies that message_id comes from search_mail, adding meaning beyond the schema. However, the prefer_html parameter remains unexplained, so the description only partially addresses the two 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?

The description clearly states the verb 'read', the resource 'one message', and specifies identification via 'id from search_mail'. It also describes the output as 'headers + decoded body'. This distinguishes it from siblings like search_mail (which returns a list) and list_attachments.

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 implies that this tool should be used after search_mail to get full message content. However, it does not explicitly state when not to use it or compare with alternatives, so it provides clear context but no exclusions.

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