read_email

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 usefully discloses output behavior (JSON, body as plain text, attachments returned as metadata only, implying save_attachment is needed to get file bytes), but says nothing about permissions, size/truncation limits, or error behavior for invalid ids.

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?

A single tightly written sentence with a parenthetical that carries real information (attachment metadata vs. disk write, plain-text body). No filler, and the core action is front-loaded.

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?

With no output schema and no annotations, the description covers the essentials: what is returned, that attachments are metadata-only, and where to go for file content. It is a bit thin on failure modes and whether the body can be omitted via includeBody, but nothing critical is missing for correct 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?

Schema description coverage is 100%, including the messageId provenance ('returned by list_emails or search_emails') and includeBody's default and text-over-HTML preference. The description adds the 'plain text' return hint but no new parameter detail, so the baseline of 3 applies.

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?

States a specific verb (Fetch) and resource (one email message) with the identifier (id) and an additional scope note about attachments. It is clearly distinguishable from siblings list_emails and search_emails, which enumerate rather than fetch a single message.

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?

Gives clear context (a single message, found via an id from list_emails/search_emails per the schema) and routes attachment retrieval to save_attachment, an explicit alternative. It stops short of stating when to prefer this over searching or when not to use it, so it is strong but not exhaustive.

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