Fetch email details by ID, including headers, plain-text body (default 2000 characters), and attachment metadata. Set body_max=0 to skip the body or raise it to read more.
读取邮件详情：头部 + 纯文本正文（默认截断 2000 字符）+ 附件清单（仅元数据）。 body_max=0 不取正文；想读全文可加大该值。id 来自 search_emails。
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | ||
| body_max | No |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and handles it reasonably: it discloses the default 2000-character truncation, the special body_max=0 behavior, and that attachments are returned as metadata only. It leaves unstated whether fetching marks the message as read and any error or permission behavior.
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?
Three short sentences, front-loaded with what is returned before the parameter notes; every clause carries information. Slightly dense Chinese phrasing with parenthetical asides, but no wasted wording.
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?
For a two-parameter read tool with an output schema already covering return shape and no annotations, the description is nearly complete: return components, truncation, and the body_max escape hatch are all stated. The remaining gap is read-side effects on message state, which an agent might reasonably wonder about.
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 supply meaning and it does: body_max's default, its zero-value semantics, and how to read the full text are all explained, and id's provenance is given. What's missing is any note on id format or whether the default truncation can be exceeded in one call.
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 gives a specific verb+resource (读取邮件详情) and enumerates exactly what is returned: headers, plain-text body, attachment list with metadata only. It partially distinguishes itself from siblings by noting attachments are metadata-only (implying get_attachments for content) and that the id originates from search_emails, though it never names an alternative tool outright.
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?
It explains how to control body retrieval (body_max=0 skips the body, larger values fetch more) and where the id comes from (search_emails), which is concrete usage context. It does not state when NOT to use this tool or explicitly route attachment downloading to get_attachments.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.