Mailbox MCP

Flag emails

flag_email

Idempotent

Flag messages - the same star/flag marker Outlook and webmail show, and the state search_emails's flagged filter finds. Purely a marker for the user's own attention; it does not move, read, or otherwise change the messages. Pass the whole set in one call.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`uids`	Yes	The UIDs to act on, from list_emails or search_emails. Pass EVERY message you want changed in ONE call - this tool acts on the whole set in a single operation, and doing it that way costs the user one call instead of one per message. Up to 500 at a time. A single message is simply a one-element array.
`mailbox`	No	IMAP folder name. Defaults to INBOX.

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

First observedSep 5, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already indicate a mutating but idempotent, non-destructive operation. The description adds valuable behavioral context beyond that: it is purely a marker, it does not move/read/change messages, and the whole set should be passed in one call. This gives an agent a clear model of the side effect.

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?

Three concise sentences packed with the essential semantics: what the flag is, what it does not do, and how to invoke it. Front-loaded with the core purpose and free of filler.

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?

For a simple two-parameter tool with strong annotations and full schema coverage, this description covers everything needed: semantics, non-effects, search integration, batching, and single-message use. No meaningful gap remains.

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 description coverage is 100%, so the schema already fully documents both parameters and the batching expectation. The description reinforces the batch behavior by saying 'Pass the whole set in one call,' but it does not add substantial meaning beyond the schema details.

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?

The description identifies a specific verb and resource: `Flag messages` with the distinctive star/flag marker. It also differentiates this from sibling tools by explicitly stating it does not move, read, or otherwise change messages, making the operation unambiguous.

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

Usage Guidelines4/5

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

The description gives clear context for when to use the tool: it is purely a user-visible attention marker and is linked to search_emails's `flagged` filter. It implies when not to use it by excluding move/read/change behaviors, though it does not explicitly name sibling tools like mark_read or unflag_email as alternatives.

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

All Mailbox MCP tools Inspect

Try in Browser

RayrunBuild, deploy, and operate MCP servers without becoming an infrastructure team.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

TDQS

A4/5.0

Disambiguation4/5

Most tools target clearly distinct actions, but there are several close pairs that require careful reading: check_bounces vs check_receipts, list_emails vs search_emails, and the send/reply/forward vs draft_email/draft_reply/draft_forward families. The descriptions are strong enough that a careful agent can disambiguate, but the boundaries are not always obvious from the tool names alone.

Naming Consistency5/5

Every tool uses a consistent snake_case verb_noun convention, such as check_bounces, list_mailboxes, send_email, and update_draft. Related operations use parallel forms like mark_read/mark_unread and flag_email/unflag_email, making the naming predictable and coherent.

Tool Count2/5

With 28 tools, this exceeds the 25+ threshold where a tool set starts to feel too heavy. Email is a broad domain and many tools are individually justified, but the surface could be consolidated, especially the draft_forward/draft_reply/draft_email and send_email/reply_email/forward_email variants.

Completeness4/5

The core email lifecycle is thoroughly covered: send, read, search, move, delete, drafts, replies, forwards, folders, flags, attachments, upload links, contacts, identities, deliverability, bounces, and receipts. The main gap is that permanent deletion is referenced as a separate operation but no such tool is actually provided, and contact/identity management is effectively read-only.

Resources

Need Help?