Source profileQuality 92/100

WYRE-AI/msp-claude-plugins/msp-claude-plugins/m365/m365/skills/mailboxes/SKILL.md

Microsoft 365 Mailboxes

Exchange Online mailboxes through Microsoft Graph: the four mailbox types and how they differ, message listing and search, inbox rules, out-of-office and forwarding, mailbox size and quota, shared-mailbox access management, and mail flow diagnostics.

Source repository stars: 42
Declared platforms: 0
Static risk flags: 0
Last source update: 2026-08-28
Source checked: 2026-08-28

Decision Compatibility Install Workflow Permissions Evidence Source FAQ

Decision brief

What it does: where it fits

Best for

Not for

Tasks that require unconfirmed production actions or broad system permissions.
Environments where the pinned source and install steps cannot be inspected.

Compatibility matrix

Platform support, with evidence labels

Platform	Status	Evidence	What to check
Codex	Not declared	No explicit evidence	Portability before use
Claude Code	Not declared	No explicit evidence	Portability before use
Cursor	Not declared	No explicit evidence	Portability before use
Gemini CLI	Not declared	No explicit evidence	Portability before use

Open the compatibility checker

Installation

Inspect first. Install second.

The source command is displayed only when detected. A safe inspection prompt is always available so your agent can explain every action before execution.

Source-detected install commandSource

npx skills add https://github.com/WYRE-AI/msp-claude-plugins --skill "msp-claude-plugins/m365/m365/skills/mailboxes"

Safe inspection promptEditorial

Inspect the Agent Skill "Microsoft 365 Mailboxes" from https://github.com/WYRE-AI/msp-claude-plugins/blob/5005f73ba2f52cd299f58aa6bb79f4e70ae87103/msp-claude-plugins/m365/m365/skills/mailboxes/SKILL.md at commit 5005f73ba2f52cd299f58aa6bb79f4e70ae87103. List every install step, command, network request, credential, file read/write, external action, and rollback step. Explain whether it fits my task. Do not install or execute anything until I approve.

Workflow

What the source asks the agent to do

01
Get Mailbox Usage / Size
For full mailbox statistics (requires Exchange admin permissions):
For full mailbox statistics (requires Exchange admin permissions):
02
Anti-triggers
"The email never arrived" — most often the message was
"The email never arrived" — most often the message wasMailbox permissions and forwarding across tenants — full-accessA suspicious forwarding rule as an active compromise — this skill
03
Mailbox Types
Review the “Mailbox Types” section in the pinned source before continuing.
Review and apply the “Mailbox Types” source section.
04
Graph API Patterns
Also supports KQL search operators: - $search="from:[email protected]" — by sender - $search="subject:urgent hasAttachments:true" — combined - $search="received=2024-01-01" — date range
$search="from:[email protected]" — by sender$search="subject:urgent hasAttachments:true" — combined$search="received=2024-01-01" — date range
05
List a User's Emails
Review the “List a User's Emails” section in the pinned source before continuing.
Review and apply the “List a User's Emails” source section.

Permission review

Static risk signals and limitations

No configured static risk pattern was detected

This is not proof of safety. Runtime behavior, indirect dependencies, and hidden external systems are outside the static scan.

Evidence record

Why each signal appears

EvidenceSourceComputedTestedEditorial

Signal	Value	Evidence type	Meaning
Quality score	92/100	Computed	Documentation, specificity, maintenance, and trust rules
Repository stars	42	Source	Repository attention, not individual Skill quality
Compatibility	0 platforms	Source	Declared in the catalog source record
Usage guide	automated source guide	Editorial	Generated or reviewed according to the visible evidence level

Pinned source

Provenance and original SKILL.md

Repository: WYRE-AI/msp-claude-plugins
Skill path: msp-claude-plugins/m365/m365/skills/mailboxes/SKILL.md
Commit: 5005f73ba2f52cd299f58aa6bb79f4e70ae87103
License: Apache-2.0
Collected: 2026-08-28
Default branch: main

View the original SKILL.md

Microsoft 365 Mailbox Management

Overview

Microsoft 365 mailboxes are managed through Exchange Online, accessible via Microsoft Graph. For MSPs, mailbox tasks range from diagnosing delivery failures and searching for lost emails to managing shared mailboxes and offboarding users. Graph provides a unified API across all mailbox types.

Anti-triggers

"The email never arrived" — most often the message was quarantined or blocked before Exchange, so nothing here will find it. Check the mail-security gateway first: mimecast, spamtitan, abnormal, ironscales, or the email-security pack. Come back here only once you know the message reached the tenant.
Mailbox permissions and forwarding across tenants — full-access delegation and forwarding rules are CIPP primitives with proper multi-tenant scope; use the cipp plugin (cipp-mailboxes).
A suspicious forwarding rule as an active compromise — this skill reads rules; interpreting them as an indicator, plus session revocation and the rest of the response, is m365-security.
Recovering a permanently deleted mailbox or item — past the retention window this is a backup restore, not a Graph read; use the backup-pack or kaseya/datto-saas-protection.

Mailbox Types

Type	Description	Common MSP Tasks
User Mailbox	Standard licensed user	Search, out-of-office, size, rules
Shared Mailbox	Team inbox, no license required	Access management, forwarding
Room/Equipment	Calendar resource booking	Availability, booking policies
Distribution Group	Email alias to multiple users	Membership, send-as

Graph API Patterns

List a User's Emails

GET /v1.0/users/{userId}/messages?$select=id,subject,from,receivedDateTime,isRead&$top=25&$orderby=receivedDateTime desc

Search for a Specific Email

GET /v1.0/users/{userId}/messages?$search="subject:invoice 2024"&$select=id,subject,from,receivedDateTime

Also supports KQL search operators:

$search="from:[email protected]" — by sender
$search="subject:urgent hasAttachments:true" — combined
$search="received>=2024-01-01" — date range

Get Message Details (with body)

GET /v1.0/users/{userId}/messages/{messageId}?$select=id,subject,from,body,receivedDateTime,attachments

Get Mailbox Settings (out-of-office, timezone)

GET /v1.0/users/{userId}/mailboxSettings

Response:

{
  "automaticRepliesSetting": {
    "status": "disabled",
    "internalReplyMessage": "",
    "externalReplyMessage": ""
  },
  "timeZone": "Eastern Standard Time",
  "language": { "locale": "en-US" }
}

Set Out-of-Office Reply

PATCH /v1.0/users/{userId}/mailboxSettings
Content-Type: application/json

{
  "automaticRepliesSetting": {
    "status": "alwaysEnabled",
    "internalReplyMessage": "<html>I'm out of office until Jan 15.</html>",
    "externalReplyMessage": "<html>I'm out of office. For urgent matters contact [email protected].</html>"
  }
}

Disable Out-of-Office Reply

PATCH /v1.0/users/{userId}/mailboxSettings
Content-Type: application/json

{
  "automaticRepliesSetting": { "status": "disabled" }
}

Get Mailbox Usage / Size

GET /v1.0/users/{userId}/mailFolders/inbox?$select=totalItemCount,sizeInBytes

For full mailbox statistics (requires Exchange admin permissions):

GET /v1.0/reports/getMailboxUsageDetail(period='D7')

Get Inbox Rules

GET /v1.0/users/{userId}/mailFolders/inbox/messageRules

Response shows rules that may affect mail delivery:

{
  "value": [
    {
      "id": "rule1",
      "displayName": "Move newsletters",
      "conditions": { "senderContains": ["newsletter"] },
      "actions": { "moveToFolder": "Newsletters" },
      "isEnabled": true
    }
  ]
}

Send an Email on Behalf of a User

POST /v1.0/users/{userId}/sendMail
Content-Type: application/json

{
  "message": {
    "subject": "Your IT support request has been resolved",
    "body": { "contentType": "HTML", "content": "<p>Your ticket #1234 is now closed.</p>" },
    "toRecipients": [{ "emailAddress": { "address": "[email protected]" } }]
  },
  "saveToSentItems": true
}

Shared Mailbox Management

Add User Access to Shared Mailbox

Shared mailbox access is managed via Microsoft 365 admin or Exchange PowerShell, not directly via Graph mailbox endpoints. Use Graph group membership or delegate access patterns.

List Users With Shared Mailbox Access

Access is represented as mailboxPermissions — check via admin APIs or Exchange PowerShell:

Get-MailboxPermission -Identity "[email protected]" | Where-Object { $_.AccessRights -eq "FullAccess" }

Mail Flow Diagnostics

Check Recent Delivery Failures

Look for NDRs (Non-Delivery Reports) in the user's inbox or sent items:

GET /v1.0/users/{userId}/messages?$filter=senderEmailAddress/address eq '[email protected]'&$select=subject,receivedDateTime,body

Common Delivery Failure Reasons

NDR Code	Meaning	Resolution
`5.1.1`	Recipient doesn't exist	Verify UPN / check aliases
`5.1.8`	Sender blocked (spam)	Review anti-spam policy
`5.2.2`	Mailbox full	Check quota, remove items
`5.7.1`	Unauthorized relay	SMTP auth settings
`5.7.606`	Sender IP blocked	Submit to Microsoft for delisting

Common MSP Workflows

Lost Email Investigation

Confirm exact sender address and approximate date
Search user's mailbox including Junk and Deleted folders
Check inbox rules that might divert messages
Review message trace in Microsoft 365 admin (requires admin access)
Check anti-spam quarantine if IT admin access available

Offboarding Mailbox Handling

Option A: Convert to shared mailbox (no license needed, data accessible)

Disable user account
Convert mailbox to shared via admin center or Graph
Grant departing user's manager full access

Option B: Forward and archive

Set auto-forward to manager
Export mailbox to PST/archive
Remove license after retention period

Option C: Auto-reply and close

Set out-of-office explaining user has left
Leave mailbox active during handover period
Remove license after business decides archival approach

Error Handling

Error	Cause	Resolution
`MailboxNotEnabledForRESTAPI`	User has no Exchange license	Assign Exchange/M365 license
`ErrorItemNotFound`	Message ID expired or moved	Search by subject/date instead
`AuthenticationError`	Token expired	Re-authenticate via OAuth flow
`TooManyRequests`	Graph throttling (429)	Retry with exponential backoff
`Forbidden (403)`	Missing Mail.Read permission	Check app registration

Permissions Required

Task	Microsoft Graph Permission
Read emails	`Mail.Read` or `Mail.ReadWrite`
Send email	`Mail.Send`
Mailbox settings	`MailboxSettings.ReadWrite`
All users' mail (admin)	`Mail.Read` (delegated + admin consent)

Related Skills

M365 Users - Account status, disable, license
M365 Calendar - Calendar and out-of-office coordination
M365 Security - Forwarding rule abuse, account compromise signs
M365 API Patterns - Auth, pagination, search syntax

Frequently asked questions

What to verify before installation and use

What does the Microsoft 365 Mailboxes source document cover?

How do I install Microsoft 365 Mailboxes?

The source record exposes this install command: npx skills add https://github.com/WYRE-AI/msp-claude-plugins --skill "msp-claude-plugins/m365/m365/skills/mailboxes". Inspect the command and pinned source before running it.

Alternatives

Compare before choosing

Computed 10045,960

coreyhaines31/marketingskills

ab-testing

When the user wants to plan, design, or implement an A/B test or experiment, or build a growth experimentation program. Also use when the user mentions "A/B test," "split test," "experiment," "test this change," "variant copy," "multivariate test," "hypothesis," "should I test this," "which version is better," "test two versions," "statistical significance," "how long should I run this test," "growth experiments," "experiment velocity," "experiment backlog," "ICE score," "experimentation program

Computed 10029,236

garrytan/gbrain

bulk-ingestion

End-to-end discipline for turning any large data source (audio libraries, email takeouts, document corpora, chat exports, API dumps) into brain pages at scale. The lifecycle spine: SCHEMA → ACCESS → TRIAL → EVALUATE → IMPROVE → CODIFY → TEST → SKILLIFY → BULK → MONITOR. State is tracked in a durable JSON manifest (see MANIFEST-PATTERN.md) so any crash, session boundary, or subagent fan-out resumes from ground truth instead of memory.

Computed 10025,136

alirezarezvani/claude-skills

app-store-optimization

App Store Optimization (ASO) toolkit for researching keywords, analyzing competitor rankings, generating metadata suggestions, and improving app visibility on Apple App Store and Google Play Store. Use when the user asks about ASO, app store rankings, app metadata, app titles and descriptions, app store listings, app visibility, or mobile app marketing on iOS or Android. Supports keyword research and scoring, competitor keyword analysis, metadata optimization, A/B test planning, launch checklist

Computed 1005,277

dotnet/skills

migrate-vstest-to-mtp

Migrates .NET test projects from VSTest to Microsoft.Testing.Platform (MTP). Use when user asks to "migrate to MTP", "switch from VSTest", "enable Microsoft.Testing.Platform", "use MTP runner", set OutputType=Exe only for test projects in Directory.Build.props, or mentions EnableMSTestRunner, EnableNUnitRunner, or UseMicrosoftTestingPlatformRunner. USE FOR: MTP behavioral differences vs VSTest (exit code 8, zero tests discovered, --ignore-exit-code, TESTINGPLATFORM_EXITCODE_IGNORE); centralizing