Fetches a single transactional email by its numeric ID, providing the full message content along with a detailed log of every SMTP delivery attempt made for it.
Retrieve one message by id, including its SMTP delivery attempts.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Numeric message id |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint=true, lowering the bar. The description adds useful behavioral context by stating that SMTP delivery attempts are included in the result, which is not present in the structured annotations. It does not mention not-found behavior, but this is a minor gap given the simple read operation.
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, front-loaded sentence states the operation, target, key, and a key result detail without any filler. Every word 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 one-parameter read-only tool with annotations, this definition is reasonably complete: it states what is retrieved and one important aspect of the return payload. Error or not-found behavior is not described, but complexity is low and no output schema is expected.
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 has 100% description coverage for the single parameter, including type, description, and minimum. The tool description adds no parameter-specific meaning, so the baseline score of 3 is appropriate.
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 names a specific verb ('Retrieve'), a concrete resource ('one message'), and the lookup key ('by id'). Adding 'including its SMTP delivery attempts' distinguishes this from list_emails and makes the return content clear.
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 use case is implied: call this when you have a message id and need a single message with delivery attempts. However, there is no explicit mention of when not to use it or reference to sibling alternatives like list_emails or get_inbound.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.