Sema: When the Hash Is the Word

Content-addressed semantics for multi-agent coordination.

Sema is a semantic commons that content-addresses meaning itself: the definition is the identifier. By deriving identifiers from the cryptographic hash of a pattern's definition, any divergence in meaning produces a distinct hash, guaranteeing that misaligned agents halt rather than fail silently.

Web: semahash.org

Install

Claude Code (zero-install via uvx)

The fastest way to add sema to Claude Code — no prior pip install needed:

claude mcp add sema -- uvx --from semahash sema mcp

This uses uv to download, install, and run sema in an isolated environment on first invocation, then caches it for subsequent calls. Same shape as npx -y in the Node ecosystem.

Permanent install (pip)

pip install semahash

For MCP server support (recommended for AI agents):

pip install "semahash[mcp]"

Then register with Claude Code:

claude mcp add sema -- sema mcp

Quick Start

Use with AI Agents (MCP)

Already covered above via the uvx or pip install paths. To add Sema to OpenClaw via mcporter:

npm install -g mcporter
mcporter config add sema --command sema --arg mcp --scope home

Or clone and install locally for development:

git clone https://github.com/emergent-wisdom/sema.git
pip install -e "./sema[mcp]"
claude mcp add sema -- sema mcp

Your agent now has access to sema_search, sema_lookup, sema_handshake, and 5 more tools. Any MCP-compatible framework works — Sema exposes a standard stdio server.

Verify it works — ask your agent: "Search sema for coordination patterns and handshake on StateLock"

Full integration guides: Claude Code | OpenClaw

Use via CLI

# Search the vocabulary
sema search "coordination"

# Look up a specific pattern
sema resolve StateLock

# Print a pattern's full definition
sema show StateLock

# Browse the graph structure
sema skeleton

# Start local API + web frontend (binds to 127.0.0.1 by default)
sema serve

Bring Your Own Vocabulary

Build a private registry from scratch — no PR or maintainer in the loop:

sema init ./mylib.db
export SEMA_DB_PATH=$(pwd)/mylib.db
sema apply --add path/to/MyPattern.json
sema search "..."

Subsequent sema commands (including sema mcp) read from your private registry. See CONTRIBUTING.md for the canonical contribution path and docs/versioning.md for the refinement and supersession policy.

Use in Python

from sema.core.actions import sema_handshake
import json

# Look up the canonical hash
result = json.loads(sema_handshake("StateLock"))
print(result["canonical_ref"])  # StateLock#7859

# Verify alignment
result = json.loads(sema_handshake("StateLock#7859"))
print(result["verdict"])  # PROCEED

Try the Protocol (No API Keys Needed)

python experiments/demos/local_handshake.py

See th

... View full README on GitHub