Apple Mail

by yu2001-s

Overview Schema Source Related Servers Discussions Admin

flag-message

Flag a single email message by ID, optionally with a color from the Apple Mail palette. Returns confirmation of the flag and applied color.

Instructions

Use when: flagging a single message (by id), optionally with a color (red/orange/yellow/green/blue/purple/gray). Returns: a confirmation that the message was flagged (and the color, when applied). Do not use when: flagging several at once (use batch-flag-messages) or removing a flag (use unflag-message). Get the id from search-messages or list-messages first. Note: flag colors are a Mail.app feature applied via AppleScript; for an IMAP-routed id the flag is set but the color is not applied (IMAP flags are colorless).

Input Schema

TableJSON Schema

Name	Required	Description	Default
`id`	Yes
`color`	No	Optional flag color (Apple Mail palette: red, orange, yellow, green, blue, purple, gray — 'grey' accepted). Omit for Mail's default flag. Colors are applied via Mail.app (AppleScript); for an IMAP-routed message id the flag is set but the color is not applied (IMAP flags are colorless).

Output Schema

TableJSON Schema

Name	Required	Description	Default
`id`	No
`ok`	No
`color`	No
`colorApplied`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 28, 2026

TDQS

A4.5/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations provided, so description carries full burden. It discloses the color limitation for IMAP-routed messages and that flag colors are a Mail.app feature applied via AppleScript. Does not mention error handling or side effects, but overall adequate.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Concise and well-structured: two short paragraphs with bullet-like clarity. Every sentence adds value.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers use case, prerequisites, behavior, edge cases (IMAP color limitation), and return. Given output schema exists, return values are not needed. Sufficient for typical usage.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 50% (id lacks description). Description adds guidance to get id from search-messages/list-messages but doesn't explain the id format beyond the schema pattern. Color parameter is already well-documented in schema, so description adds little extra.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description explicitly states it flags a single message by id, optionally with a color, and distinguishes from batch-flag-messages and unflag-message. It also specifies the return value (confirmation and color).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides clear 'Use when' and 'Do not use when' conditions, names alternative tools, and instructs to get the id from search-messages or list-messages first.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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