Mailbox MCP

Check for delivery and read confirmations

check_receipts

Read-onlyIdempotent

Find the confirmations that came back for messages this mailbox sent. Two kinds arrive: a DELIVERY confirmation, meaning the recipient's SERVER accepted the message, and a READ receipt, meaning their mail program reported that the message was opened. Use it after sending something important, or when the user asks whether a message got there. Pass the messageId from a send result to ask about one specific message. WHAT A MISSING RECEIPT MEANS: NOTHING AT ALL, and you must say so rather than let the user read silence as "they ignored me". A read receipt only exists if the recipient's mail program offers one AND they agreed to send it - consumer Gmail never does, Google Workspace only if an administrator switched it on, and Apple Mail only if the person changed a setting that ships off. Most messages will never produce one even when they are read within minutes. A read receipt that DOES arrive means the message was opened, not that it was read or understood, and one reporting deleted means it was thrown away unopened. This finds a receipt only if the message ASKED for one: set requestReadReceipt on send_email when you send it. Nothing here can be requested retrospectively.

Input Schema

TableJSON Schema

Name	Required	Description
`days`	No	How far back to look, in days. Defaults to 7.
`mailboxes`	No	Folders to scan. Defaults to INBOX and Junk.
`messageId`	No	Only report confirmations for this message, using the `messageId` a send result gave you. Leave it out to see everything that came back.

Schema Changelog

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

First observedSep 5, 2026

TDQS

A4.7/5.0

Behavior5/5

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

The description goes far beyond the readOnly/openWorld/idempotent annotations by explaining that a missing receipt means nothing, the conditions under which read receipts exist, that a receipt only means opened not read, and that requests cannot be made retroactively. This is rich, honest behavioral disclosure that prevents serious misinterpretation.

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?

The description is long but every sentence carries essential information: tool purpose, receipt types, when to use, how to scope, and critical caveats about missing receipts. The most important scoping instruction is front-loaded, and the content is organized clearly rather than padded.

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 read-only query tool with no output schema, the description fully covers what the tool does, what the results mean, how to narrow results, and the critical prerequisite that a read receipt must have been requested at send time. Nothing essential is missing for an agent to select and invoke it correctly.

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

Parameters4/5

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

The schema already provides 100% coverage with descriptions for days, mailboxes, and messageId. The description adds meaningful value by explaining how to use messageId from a send result, the default behavior when omitted, and the meaning of receipt-related statuses. This goes beyond the baseline schema-only documentation.

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 opens with a specific verb and resource: finding confirmations for messages this mailbox sent. It clearly distinguishes the two kinds of confirmations (DELIVERY vs READ) and the exact meaning of each, making the tool's purpose unambiguous relative to sibling tools.

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?

It explicitly states when to use the tool: after sending something important or when the user asks whether a message arrived. It also explains how to scope by messageId and the prerequisite of requesting a receipt during send. It does not explicitly name alternatives like check_bounces, but the usage context is clear enough.

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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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

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