Fetch a specific email by ID, return its body as Markdown, and mark it as read by default. Set mark_read to false to preserve unread status.
Read one message with its body as Markdown. Marks it as read unless mark_read is false.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Message id from list_messages | |
| mark_read | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden, and it discloses the critical surprise: a 'read' operation mutates state by marking the message read unless mark_read is false. It omits any mention of permissions, failure behavior for a bad id, or whether attachments are included.
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 short sentences, the return format front-loaded ahead of the side-effect caveat. Every clause carries information and nothing is padded.
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 tool with no output schema, the description covers purpose, returned representation, and the state-changing default, which is what an agent needs to call it safely. The main remaining gap is routing guidance against the other read/attachment siblings.
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 coverage is only 50% because mark_read has no schema description, and the description compensates by defining exactly what it does ('unless mark_read is false'). The id parameter's meaning is already carried by the schema text 'Message id from list_messages'.
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 and resource ('Read one message') plus the return format ('body as Markdown'), which distinguishes it from the plural list_messages sibling. It stops short of naming the sibling it replaces, so an agent must infer the boundary between listing and reading.
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 statement of when to use this versus get_attachment, mark_message, or list_messages, and no prerequisites are given. Usage is only implied by the verb, leaving the agent to guess at routing among eleven siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.