read_email

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

Annotations already provide readOnlyHint, openWorldHint, idempotentHint. The description adds critical behavioral context: attachments are listed by name+mime by default, and embedding requires include_attachments=true with a size limit caveat. This goes beyond annotations and helps the agent understand context limitations.

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?

Two sentences, front-loaded with main purpose, no redundant phrases. Every sentence 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 complexity and sibling tools, the description is mostly complete. It could mention that for file downloads, use download_attachments, but the output schema likely documents return values. The caveat about attachment size and context is valuable.

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 50% (2 of 4 parameters have descriptions). The description adds meaning for 'uid' (implying it comes from list_recent/search) and 'include_attachments' (explains behavior and context limit). It does not cover 'folder' or 'account', but their defaults are clear from schema.

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 ('Fetch'), the resource ('message'), and the content retrieved ('full headers + body', 'attachments listed by name+mime'). It distinguishes from sibling tools like list_recent (list messages) or download_attachments (download files).

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 usage for reading a specific email, but does not explicitly state when to use this tool vs alternatives like list_recent or download_attachments. No guidance on when not to use or prerequisites.

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