list_attachmentsRetrieve attachment metadata (ID, name, type, size, inline status) for a specified Outlook message without downloading file contents.
List a message's attachments as metadata only (id, name, contentType, size, isInline). Attachment bytes are intentionally not returned.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Message id (from list_messages or search_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, idempotentHint, openWorldHint, and destructiveHint false EB, so the safety profile is covered. The description adds valuable behavioral context beyond annotations by explicitly stating that only metadata is returned and attachment bytes are intentionally omitted, which is a meaningful behavioral constraint an agent needs to know.
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 sentence with no filler. It front-loads the core action and resource, then immediately specifies the output scope and the intentional exclusion of bytes. Every word contributes to the agent's understanding.
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?
Given the tool is simple, has one well-documented parameter, strong annotations, and no output schema is present, the description provides all essential context: what is listed, what fields are returned, and what is not returned. 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%, and the schema already explains that 'id' is a message id from list_messages or search_messages. The tool description adds no additional parameter-level meaning beyond 'a message's attachments,' so the baseline of 3 is appropriate since the schema carries the burden.
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 uses a specific verb and resource: 'List a message's attachments as metadata only.' It also clarifies the tool returns metadata fields like id, name, contentType, size, and isInline, and explicitly excludes attachment bytes, which distinguishes it from any content-returning alternative. This is unambiguous and directly tied to the tool's name.
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 clearly implies the tool is used when a message's attachments are needed, and the schema reinforces the input comes from list_messages or search_messages. It does not explicitly state when not to use it or name alternatives among siblings, but none of the siblings provide attachment listing, so the context is sufficiently clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.