Pin or unpin an email in Fastmail to control its priority in your inbox, making important messages easier to find.
Pin or unpin an email
| Name | Required | Description | Default |
|---|---|---|---|
| pinned | No | true to pin, false to unpin | |
| emailId | Yes | ID of the email to pin/unpin |
Changes observed during successful MCP inspections.
v1.8.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations provided; description only states action without disclosing side effects (e.g., visual changes, reversibility) or behavioral traits beyond the basic 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?
Extremely concise (5 words) with no waste. Appropriate for a simple tool, though lacks structural elements like examples or bullet points.
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?
Adequate for a straightforward toggle operation, but missing details on return value or effect on email order/visibility. Could be more informative given no output schema.
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 covers all parameters with descriptions. The tool description adds no extra semantic value beyond the schema content.
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?
Clearly states action (pin/unpin) and resource (email). Distinguishes from sibling 'bulk_pin' by implication, but lacks explicit scope indication.
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?
No guidance on when to use this tool versus alternatives like bulk_pin or other email operations. No context on prerequisites or conditions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.