Attach a file to a specified Outlook email draft using message ID and Base64-encoded content.
Add an attachment to an email draft
| Name | Required | Description | Default |
|---|---|---|---|
| name | Yes | Name of the attachment file | |
| messageId | Yes | The ID of the email (draft) to add attachment to | |
| contentType | Yes | MIME type of the attachment | |
| contentBytes | Yes | Base64-encoded content of the attachment |
Changes observed during successful MCP inspections.
v2.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must disclose behavioral traits. It only says 'Add an attachment' but does not mention whether it appends, overwrites, or any side effects. The mutation is implied but lacks detail like required draft state.
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 a single, front-loaded sentence with no waste. It conveys the core purpose efficiently.
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?
Despite having 4 required parameters and no output schema, the description offers no context about return values, error conditions, or post-invocation behavior. It is too minimal for a state-modifying tool.
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 100% with clear parameter descriptions, so the description adds no additional meaning. Baseline of 3 is appropriate as the schema handles parameter semantics.
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 clearly states the verb 'add', the resource 'attachment', and the target context 'email draft'. It immediately distinguishes from sibling tools like outlook_download_attachment and outlook_list_attachments.
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 provides no guidance on when to use this tool versus alternatives (e.g., adding attachments during draft creation). It only states the action without context or prerequisites.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.