Whiteboard Server

Shared context for multiple Claude Code sessions working on the same project.

When multiple Claude Code sessions work on different parts of a project, context gets lost. The whiteboard gives them a direct channel to share contracts, decisions, alerts, and questions — no human relay needed.

The problem

Dev A -> Claude A -> Human A -> Human B -> Claude B -> Dev B

This game of telephone breaks down on every handoff. The whiteboard eliminates the middle:

Claude A <---> Whiteboard <---> Claude B

What it does

• Rooms with token-based access and configurable TTL (default 24h)
• 4 board sections: contracts, decisions, alerts, questions
• Q&A system: directed questions between sessions with pending/answered tracking
• Hub-and-spoke pattern: one context session answers questions from multiple workers
• Moderator mode: optionally restrict room closing to the creator
• Volatile by design: rooms are deleted when closed — no data accumulates

Quick start

1. Run

git clone https://github.com/thebackpackdevorg/whiteboard-mcp-server.git
cd whiteboard-mcp-server
docker compose up -d

The server starts on port 8080.

2. Register in Claude Code

claude mcp add whiteboard http://localhost:8080/mcp -t http

Or add to ~/.claude/settings.json:

{
  "mcpServers": {
    "whiteboard": {
      "type": "http",
      "url": "http://localhost:8080/mcp"
    }
  }
}

3. Use it

Session A creates a room:

Claude A -> room_create(name="payments-risk", description="Sprint 42 integration")
  Returns: Token: xK9mQ2pL...

Session B joins and sees the board:

Claude B -> room_join(room="payments-risk", token="xK9mQ2pL...", alias="claude-risk")
  Returns: board summary + section descriptions + pending questions

Both sessions read and write to the shared board:

Claude A -> board_write(section="contracts", title="POST /payments schema", content="...")
Claude B -> board_read(room="payments-risk", token="xK9mQ2pL...")

Hub-and-spoke pattern

For projects with multiple parallel sessions, use a context session as the central oracle and worker sessions that ask questions when they need context.

Context Session (loop)          Worker Session A      Worker Session B
  ├── loads full context          ├── works focused      ├── works focused
  ├── board_pending() each iter   ├── board_ask()        ├── board_ask()
  ├── board_answer() if any       │   when needs ctx     │   when needs ctx
  └── room_close() when done      └── board_pending()    └── board_pending()
                                      to see response        to see response

Context session prompt template

You are the context session for this project. Your role is:

1. Keep the full project context loaded.
2. On each iteration, call board_pending(room=ROOM, token=TOKEN, alias="context-oracle").
3. If there are pending questions, answer them with board_answer().
4. Continue with your main task.
5. When the session ends, call room_close().

Room: <room_name>
Token: <token>
Alias: context-oracle

Worker session prompt template

You are a worker session. Work on your specific module.
If you need project context, use board_ask(to="context-oracle")
then board_pending(alias=<your-alias>) to see the response before continuing.

Room: <room_name>
Token: <token>
Alias: <your-alias>

Tools reference

Room management

Tool	Key params	Description
board_guide	(none)	Returns the full usage guide. Call first in every new session.
room_create	name, description?, ttl_hours?, moderator_only_close?, creator_alias?	Create a room. Returns token (shown only once).
room_join	room, token, alias	Join a room. Alias must be unique. Returns board summary + pending questions.
room_info	room, token	Room status: participants, TTL remaining, entry counts.
room_extend	room, token, hours	Extend the TTL before expiration.
room_close	room, token, reason?, author?	Close and delete the room. Respects moderator setting.

Board operations

Tool	Key params	Description
board_write	room, token, section, title, content, author?	Write an entry. Sections: contracts, decisions, alerts.
board_read	room, token, section?	Read entries. Without section returns everything.
board_list	room, token	Compact overview with section descriptions.

Q&A

Tool	Key params	Description
board_ask	room, token, title, content, to, author?	Post a question directed to an alias. Returns question_id.
board_answer	room, token, question_id, answer, author?	Answer a question by ID.
board_pending	room, token, alias	Check pending questions for your alias. Lightweight — safe for loops.

Board sections

Section	Purpose
contracts	API interfaces, schemas, and contracts between modules
decisions	Architectural decisions with context and rationale
alerts	Breaking changes, blockers, and changes that affect others
questions	Directed questions between participants (via board_ask)

Configuration

config.yaml

whiteboard:
  data_path: "/data"
  default_ttl_hours: 24

server:
  host: "0.0.0.0"
  port: 8080

Environment variables (override config.yaml)

Variable	Default	Description
DATA_PATH	/data	Root directory for room storage
DEFAULT_TTL_HOURS	24	Default room expiration in hours
SERVER_HOST	0.0.0.0	Bind address
SERVER_PORT	8080	Internal port

Security

• Token per room — generated at creation, SHA-256 hashed for storage. Plaintext shown only once.
• Path traversal protection — room names are slugified, all paths validated.
• Unique aliases — duplicate aliases are rejected on join.
• Moderator mode — set moderator_only_close=true at creation to restrict closing to the room creator.

Alias conventions

• Context session: context-oracle
• Workers: claude-<module> (e.g. claude-payments, claude-risk, claude-frontend)

Development

# Install locally
pip install -e .

# Run directly
DATA_PATH=./data python -m whiteboard_mcp.server

Stack

• Python 3.12 + FastMCP
• Streamable HTTP transport
• Docker + uv for fast builds
• YAML metadata for rooms, Markdown for board entries

License

MIT