read_email

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states 'Retrieve,' implying a read operation, but does not disclose whether reading marks the email as read, whether authentication/scopes are required, or how invalid message IDs are handled. The minimal one-liner leaves key side-effect questions unanswered.

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?

One sentence with zero filler and the operative verb 'Retrieve' front-loaded. It is efficient, though it sacrifices substance for brevity; this is acceptable given the simple signature, so it earns a 4 rather than a 5.

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?

The tool is simple (one parameter, output schema present), so return-value coverage is handled. However, with no annotations and 17 sibling tools, the absence of usage guidance and side-effect disclosure leaves the definition incomplete for an agent deciding between read_email, download_attachment, and search_emails.

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 100%, so the single parameter message_id is already documented as 'ID of the email message to retrieve.' The tool description adds no extra meaning beyond the schema, matching the baseline of 3 for high-coverage schemas.

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 states a clear verb and resource: 'Retrieve the content of a specific email.' It is distinguishable from siblings like search_emails (finds emails), send_email (creates outgoing mail), and trash_email (mutates state). However, it does not explicitly mention that retrieval is by message_id, nor does it contrast with download_attachment, so it falls just short of full differentiation.

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?

There is no guidance on when to use this tool versus the 17 siblings. It does not say that the caller should first obtain a message_id from search_emails, nor does it exclude use cases such as retrieving only attachments. No context, no exclusions, no alternatives—score reflects the complete absence of usage direction.

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