get_messageFetch a full email by ID to read its body before replying or summarizing, preventing invented content.
Read one message in full, including its body, by the id that list_messages returned. Read the message before replying to it or summarising it; a reply written from the subject line alone invents its own content.
| Name | Required | Description | Default |
|---|---|---|---|
| message_id | Yes | id from list_messages |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds that the full message including its body is returned, which is useful behavioral context. It also explains why reading the full message matters before replying or summarising. No contradiction with annotations exists.
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?
The description is two compact sentences with no filler. The core action is front-loaded in the first sentence, and the second sentence provides essential usage guidance and rationale. Every clause earns its place.
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 single-parameter read-only tool with readOnlyHint and destructiveHint annotations, the description covers what is returned ('in full, including its body'), where the id comes from, and when to call it. With no output schema, the description sufficiently sets expectations for the response without needing a field-by-field breakdown.
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?
The input schema already documents message_id with the description 'id from list_messages', giving 100% parameter coverage. The description repeats this provenance but does not add format, type nuance, or additional meaning beyond the schema. Baseline 3 is appropriate given high schema coverage.
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 specific verb and resource: 'Read one message in full, including its body.' It also distinguishes itself from list_messages by clarifying that this tool retrieves the full body by an id returned from list_messages, and from get_event by focusing on messages. This makes the tool's purpose unambiguous.
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 explicitly instructs when to use the tool: 'Read the message before replying to it or summarising it.' It also establishes the expected workflow by tying message_id to 'list_messages' and warns about the consequence of skipping this step: 'a reply written from the subject line alone invents its own content.' This gives clear context and rationale for use.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.