Mess MCP

MESS MCP Server

Overview

The MESS MCP Server provides Claude Desktop with tools to create and manage physical-world task requests. It syncs with GitHub (or local files) to store request threads.

Tools

mess - Send MESS Protocol Messages

Create new requests or update existing ones using free-form YAML.

Input: YAML-formatted MESS message

Why YAML? The mess tool accepts raw MESS protocol messages, allowing you to:

• Include any valid MESS protocol fields, not just common ones
• Add custom context, metadata, or instructions
• Construct complex multi-part messages
• Use the full expressiveness of the MESS protocol

The examples below show common patterns, but you can include any fields defined in the MESS protocol specification.

Creating a Request

- v: 1.0.0
- request:
    intent: Check if the garage door is closed
    context:
      - Getting ready for bed
      - Want to make sure house is secure
    priority: normal
    response_hint:
      - image
      - text

Response:

ref: "2026-02-01-001"
status: pending
message: "Request created: 2026-02-01-001"

Updating a Request

Send a status update:

- status:
    re: "2026-02-01-001"
    code: claimed

Cancel a request:

- cancel:
    re: "2026-02-01-001"
    reason: "No longer needed"

mess_status - Check Request Status

Query pending requests or get details on a specific thread.

List All Active Requests

ref: null

Response:

- ref: "2026-02-01-001"
  status: pending
  intent: Check if the garage door is closed
  requestor: claude-desktop
  executor: null
  priority: normal
  created: "2026-02-01T22:00:00Z"
  hasUpdates: true    # changed since last mess_status call

- ref: "2026-02-01-002"
  status: claimed
  intent: What's in the fridge?
  requestor: claude-desktop
  executor: teague-phone
  priority: normal
  hasUpdates: false   # no changes since last check

Note: The hasUpdates flag indicates whether the thread changed since your last mess_status call. New threads always have hasUpdates: true. Use mess_wait instead of polling if you want to wait for changes efficiently.

Get Specific Thread

ref: "2026-02-01-001"

Response (v2.1.0 format):

ref: "2026-02-01-001-garage-check"
status: completed
intent: Check if the garage door is closed
requestor: claude-desktop
executor: teague-phone
messages:
  - from: claude-desktop
    received: "2026-02-01T22:00:00Z"
    MESS:
      - v: "1.0.0"
      - request:
          id: garage-check
          intent: Check if the garage door is closed

  - from: teague-phone
    received: "2026-02-01T22:05:00Z"
    re: "2026-02-01-001-garage-check"      # message-level reference
    MESS:
      - status:
          code: completed
      - response:
          content:
            - image:
                resource: "content://2026-02-01-001-garage-check/att-002-image-door.jpg"
                mime: "image/jpeg"
                size: 245891
            - "All clear - garage door is closed and locked"

attachments:
  - name: att-002-image-door.jpg
    resource: "content://2026-02-01-001-garage-check/att-002-image-door.jpg"

Note: Images are returned as content:// resource URIs instead of inline base64 to keep responses lightweight. Use mess_fetch to fetch attachment content when needed.

Configuration

GitHub Mode (Recommended)

{
  "mcpServers": {
    "mess": {
      "command": "node",
      "args": ["/path/to/mcp/index.js"],
      "env": {
        "MESS_GITHUB_REPO": "username/mess-exchange",
        "MESS_GITHUB_TOKEN": "github_pat_xxxxx",
        "MESS_GITHUB_ONLY": "true",
        "MESS_AGENT_ID": "claude-desktop"
      }
    }
  }
}

Local Mode

{
  "mcpServers": {
    "mess": {
      "command": "node",
      "args": ["/path/to/mcp/index.js"],
      "env": {
        "MESS_DIR": "~/.mess",
        "MESS_AGENT_ID": "claude-desktop"
      }
    }
  }
}

Hybrid Mode (Local + GitHub Sync)

{
  "mcpServers": {
    "mess": {
      "command": "node",
      "args": ["/path/to/mcp/index.js"],
      "env": {
        "MESS_DIR": "~/.mess",
        "MESS_GITHUB_REPO": "username/mess-exchange",
        "MESS_GITHUB_TOKEN": "github_pat_xxxxx",
        "MESS_AGENT_ID": "claude-desktop"
      }
    }
  }
}

mess_capabilities - Discover Available Capabilities

List physical-world capabilities that executors in this exchange can perform.

Input: Optional tag filter

List All Capabilities

# No input needed

Response:

- id: camera
  description: Take and attach photos
  tags: [attachments]
- id: check-door
  description: Check if doors are locked or closed
  tags: [security, physical-access]
- id: hands
  description: Has human hands for physical manipulation
  tags: [physical-access]

Filter by Tag

tag: security

Response:

- id: check-door
  description: Check if doors are locked or closed
  tags: [security, physical-access]
- id: check-stove
  description: Verify stove/oven is turned off
  tags: [security, safety]

Use this to understand what kinds of tasks you can request. Capabilities are defined in capabilities/*.yaml in the exchange.

mess_request - Create Request (Simple)

A simpler alternative to the raw mess tool for creating requests.

Input:

intent: "Check if the garage door is closed"
context:
  - "Getting ready for bed"
priority: elevated
response_hints:
  - image

Response:

ref: "2026-02-01-001"
status: pending
message: "Request created"

mess_answer - Answer Question

Respond to an executor's question when status is needs_input.

Input:

ref: "2026-02-01-001"
answer: "The living room ceiling light, not the lamp"

mess_cancel - Cancel Request

Cancel a pending or in-progress request.

Input:

ref: "2026-02-01-001"
reason: "No longer needed"  # optional

mess_wait - Wait for Changes

Wait for changes to threads instead of polling mess_status repeatedly.

Input:

ref: "2026-02-01-001"  # optional: wait for specific thread
timeout: 60             # optional: seconds (default: 60, max: 43200 / 12 hours)

Response:

updated:
  - ref: "2026-02-01-001"
    status: claimed
    hasUpdates: true
waited: 5
timedOut: false

Adaptive polling: Poll frequency scales with timeout (~30 polls total):

• 60s timeout → polls every 2s
• 5 min → every 10s
• 1 hour → every 2 min
• 12 hours → every 24 min

When to use:

• After creating a request, call mess_wait to be notified when claimed/completed
• Returns immediately if thread changed since wait started
• Use for efficient long-running waits instead of polling

Example workflow:

# 1. Create a request
mess_request:
  intent: "Check if the garage door is closed"

# 2. Wait for it to be completed (up to 1 hour)
mess_wait:
  ref: "2026-02-01-001"
  timeout: 3600

# 3. Response returns when status changes or timeout

mess_fetch - Fetch Resource Content

This is how you retrieve images and attachments. When mess_status returns content:// URIs, use this tool to fetch the actual content.

Input:

uri: "content://2026-02-01-001/photo.jpg"

Supported URI schemes:

• content://{ref}/{filename} - Attachments (images, files)
• thread://{ref} - Full thread data (envelope + messages)
• thread://{ref}/envelope - Thread metadata only
• thread://{ref}/latest - Most recent message
• mess://help - This documentation

Response for images:

uri: "content://2026-02-01-001/photo.jpg"
mimeType: "image/jpeg"
encoding: "base64"
data: "/9j/4AAQSkZJRg..."

Response for thread data: Returns the thread content as YAML.

Example workflow:

# 1. Check status, see there's an image
mess_status:
  ref: "2026-02-01-001"
# Response includes: resource: "content://2026-02-01-001/photo.jpg"

# 2. Fetch the image
mess_fetch:
  uri: "content://2026-02-01-001/photo.jpg"
# Response includes base64 image data

Request Fields

Free-Form Extensions

The MESS protocol is extensible. Beyond the standard fields above, you can include:

- v: 1.0.0
- request:
    intent: Check the garden irrigation system
    context:
      - Haven't watered in 3 days
    priority: normal
    # Standard fields above, custom fields below:
    location: backyard
    equipment_needed:
      - hose access
      - manual valve knowledge
    safety_notes:
      - Watch for wasps near the shed
    deadline: before 6pm today

Custom fields are preserved in the thread and visible to executors. Use them for domain-specific context that doesn't fit the standard fields.

Status Codes

Common Patterns

Create and Wait

# 1. Create request
mess:
  - v: 1.0.0
  - request:
      intent: Is anyone home?

# 2. Periodically check status
mess_status:
  ref: "2026-02-01-001"

# 3. When completed, read the response

Urgent Request

- v: 1.0.0
- request:
    intent: Did I leave the stove on?
    context:
      - Just left the house
      - Can't remember if I turned it off
    priority: urgent
    response_hint:
      - image
      - text

Follow-up After needs_input

# Original request got needs_input status
# Executor asked: "Which light?"

# Send clarification (v2.1.0: answer block, message-level re: handled automatically)
- answer:
    id: light-clarification
    value: "The living room ceiling light, not the lamp"

Resources

The MCP server uses content:// and thread:// URIs for attachments and thread data.

Fetching Attachments

When mess_status returns a thread, images and files are referenced as resource URIs:

image:
  resource: "content://2026-02-01-001/att-002-image-door.jpg"
  mime: "image/jpeg"
  size: 245891

To fetch the actual image, use mess_fetch:

mess_fetch:
  uri: "content://2026-02-01-001/att-002-image-door.jpg"

This keeps status responses lightweight and avoids blowing up context with large base64 payloads.

Resource URI Format

content://{thread-ref}/{attachment-filename}

Examples:

• content://2026-02-01-001-garage-check/att-002-image-door.jpg
• content://2026-02-01-003-fridge/att-005-image-contents.jpg

Thread Resources

Read thread data with attachments automatically rewritten to content:// URIs:

thread://{ref}          # Full thread (envelope + messages)
thread://{ref}/envelope # Just metadata (status, executor, history)
thread://{ref}/latest   # Most recent message only

Example - Read full thread:

# Request: thread://2026-02-01-001

# Response:
envelope:
  ref: "2026-02-01-001"
  status: completed
  intent: Check the garage door
messages:
  - from: claude-desktop
    MESS:
      - request:
          intent: Check the garage door
  - from: teague-phone
    MESS:
      - response:
          content:
            - image:
                resource: "content://2026-02-01-001/att-001-door.jpg"
            - "Door is closed"

Example - Read just envelope:

# Request: thread://2026-02-01-001/envelope

# Response:
ref: "2026-02-01-001"
status: completed
executor: teague-phone
updated: "2026-02-01T22:05:00Z"

Error Handling

Thread not found:

error: "Thread 2026-02-01-999 not found"

Missing required field:

error: "Missing re: field"

GitHub API error:

error: "GitHub API error: 401"

File Locations

macOS

• Config: ~/Library/Application Support/Claude/claude_desktop_config.json
• Local MESS dir: ~/.mess/

Linux

• Config: ~/.config/claude/claude_desktop_config.json
• Local MESS dir: ~/.mess/

Windows

• Config: %APPDATA%\Claude\claude_desktop_config.json
• Local MESS dir: %USERPROFILE%\.mess\