mail_flags_updateUpdate email flags to mark messages as read or unread, star or unstar them, and set answered or draft status. Only specified flags change, leaving others intact.
Use this to mark a message read or unread, star or unstar it, or update answered and draft flags. Only explicitly provided fields change.
| Name | Required | Description | Default |
|---|---|---|---|
| read | No | ||
| draft | No | ||
| starred | No | ||
| answered | No | ||
| messageId | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate this is a write operation with no read-only, destructive, or idempotent guarantees. The description adds the useful detail that omitted fields are left unchanged, but it does not disclose return values, error behavior, or any side effects beyond flag updates.
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 concise, uses two short sentences, and front-loads the purpose before adding the partial-update caveat. Every word contributes meaning.
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 simple flag-update tool, the description is sufficient to know what the tool does and which fields matter. However, there is no output schema or mention of what the tool returns after a successful update, which leaves some ambiguity for an agent.
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 descriptions are absent (0% coverage), but the description maps the boolean flags (read/read, starred/star, answered/answered, draft/draft) and implies messageId identifies the target. This compensates for the missing schema descriptions.
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?
Description states the exact verbs and resources: mark a message read/unread, star/unstar, and update answered/draft flags. It clearly distinguishes this tool from sibling tools focused on moving, deleting, or drafting messages.
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 explains partial-update semantics ('Only explicitly provided fields change') but gives no explicit guidance on when to prefer this tool over sibling tools such as mail_draft_update or mail_move. No alternatives or conditions are mentioned.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.