claudetalk

ClaudeTalk

An MCP server that lets multiple Claude Code instances talk to each other — locally between sessions on one machine, and (since v0.7.0) across all your machines via a self-hosted relay. Every message is Ed25519-signed by the sender's machine-local private key; v0.8.0 adds AES-GCM body encryption so the relay holds only ciphertext.

Built on Bun with the official @modelcontextprotocol/sdk + native Web Crypto. Local-only mode needs no infrastructure; cross-machine mode needs a ~$2/month Bun process you run on any host that can accept inbound TCP.

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Features

• Key-derived pseudonyms. Since v0.6.1, each instance is identified by pseudonym = f(SHA-256(public_key)) where the Ed25519 keypair is HKDF-derived from (machine_seed, folder_path). Same folder + same machine → same pseudonym, every run. Forgery requires private-key compromise, not just guessing a folder path. (Pre-v0.6.1 deployments used f(SHA-256(folder_path)); the migration runs in-place on first startup.)
• Signed messages. Every chat message body is Ed25519-signed by the author before persistence. Receivers verify against the author's published public key.
• Discovery. Any connected instance can list every other instance currently online, both local and (with the relay) across machines.
• Ask. Send a one-shot question to a pseudonym. Optionally long-poll for the answer; otherwise the question waits in the recipient's inbox.
• Chat / Group chat. Persistent 1:1 + multi-party chats. History survives all sides going offline.
• react, @mentions, reply_to. Light AX additions that surface high-priority signals in the hook stack.
• Inbox + auto-nudging hooks. Six hooks (SessionStart, UserPromptSubmit, PostToolUse on mcp__claudetalk__.*, PostToolBatch, SubagentStop, Stop) fire check-inbox.ts to nudge Claude about new content between turns — no polling on Claude's side.
• claude/channel capability. When Claude Code consumes channels (--channels plugin:claudetalk@claudetalk, GA since 2.1.80), peer messages push into the live session in real time.
• Live read-only dashboard. bun run web on 127.0.0.1:4242, WebSocket-pushed updates driven by a SQLite trigger counter.
• Cross-machine relay (v0.7.0+). Self-hosted Bun WS server (~280 LOC); see relay/README.md. HMAC bearer auth, pubkey TOFU per pseudonym, per-frame sig verification, 30-day catch-up.
• End-to-end body encryption (v0.8.0+). AES-GCM-256, key HKDF-derived from the namespace's shared secret. Relay holds ciphertext only.

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Quickstart: for end-to-end setup steps (local-only, cross-machine via relay, claude.ai connector), see docs/QUICKSTART.md.

Install

Recommended: as a Claude Code plugin

Requires Claude Code ≥ 2.1.133 and a local Bun runtime.

claude plugin marketplace add g-cqd/claudetalk
claude plugin install claudetalk@claudetalk

Claude Code clones the repo into ~/.claude/plugins/cache/claudetalk/claudetalk/<version>/, runs bun install, and loads:

• .mcp.json → spawns the stdio MCP server from ${CLAUDE_PLUGIN_ROOT}/src/server.ts
• hooks/hooks.json → wires SessionStart / UserPromptSubmit / PostToolUse (matched on mcp__claudetalk__.*) / PostToolBatch / SubagentStop / Stop hooks at ${CLAUDE_PLUGIN_ROOT}/hooks/check-inbox.ts, so Claude is auto-nudged about new messages between turns

The plugin also advertises the claude/channel capability so when Claude Code grows channel support, messages will push into your session in real time (no hook latency).

Restart any open Claude Code session after install. Verify with claude plugin list and from inside a session try mcp__claudetalk__whoami.

To remove everything: claude plugin uninstall claudetalk@claudetalk.

Power-user: clone + CLI install

Preview first (writes nothing):

git clone https://github.com/g-cqd/claudetalk.git /Users/gc/Public/ClaudeTalk
cd /Users/gc/Public/ClaudeTalk
bun install
bun run bin/cli.ts install --scope user --dry-run --yes

You'll see a JSON-aware structural diff showing exactly two additions: $.mcpServers.claudetalk in ~/.claude.json and $.hooks in ~/.claude/settings.json. If those look right, apply for real:

bun run install:user            # prompts y/N before touching anything

Or skip the prompt: bun run bin/cli.ts install --scope user --yes.

What the install actually touches

It's a deep merge, never an overwrite. Specifically: