Add or remove IMAP email flags by UID to mark messages as read, flagged, or important. Specify a mailbox to manage message status in your inbox or other folders.
Adds or removes flags on an email message by UID
| Name | Required | Description | Default |
|---|---|---|---|
| uid | Yes | ||
| flags | Yes | ||
| action | Yes | ||
| mailbox | No | INBOX |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It says the tool mutates flags but discloses nothing about whether removals of absent flags error, whether flags are IMAP keywords (\Seen, \Flagged), required permissions, or reversibility.
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?
One tight sentence with the verb front-loaded and no filler. It is efficient, though its brevity reflects under-specification rather than disciplined economy.
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?
A mutation tool with no annotations, no output schema, and zero parameter documentation needs substantially more than one clause. Valid flag values, error behavior, and the mailbox default are all missing.
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 0%, so the description must compensate. It names UID and the add/remove action, but says nothing about valid flag string values (the least obvious parameter), nor that mailbox defaults to INBOX.
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?
States a specific verb pair (adds/removes) and resource (flags on an email message), plus the lookup key (UID). It reads clearly against siblings like move-email and read-email, though what a "flag" actually is remains undefined.
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 prefer this over siblings, no prerequisites, no note that mailbox defaults to INBOX or that flag operations are per-message. The agent must infer all usage context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.