@arkheia/mcp-server
Advanced tools
Arkheia MCP Server — Fabrication detection for LLM outputs. Detect hallucination in any model's output with a single tool call.
Know when your AI is making things up.
Arkheia screens model responses for fabrication using behavioural fingerprinting. Works with Claude, GPT, Gemini, Grok, Llama, Mistral, and 30+ other models. One tool call. Real-time risk scoring.
Free tier: 1,500 detections/month. No credit card.
Requires:
- Node 18+
- Python 3.10–3.13 with working pyexpat
macOS note: Homebrew's current `brew install python` installs 3.14,
which has a broken pyexpat link. Use `brew install python@3.12` until
Homebrew ships a fix. Verify with:
python3.12 -c "import pyexpat, ensurepip"
npm install -g @arkheia/mcp-server
Get a free API key at arkheia.ai/mcp/account, or via the CLI:
curl -X POST https://arkheia-proxy-production.up.railway.app/v1/provision \
-H "Content-Type: application/json" \
-d '{"email": "you@example.com"}'
Set your key:
export ARKHEIA_API_KEY="ak_live_..."
Each AI CLI has a slightly different mcp add command. Use the one that matches your tool. All assume you've installed globally with npm install -g.
claude mcp add arkheia -s user \
-e ARKHEIA_API_KEY="$ARKHEIA_API_KEY" \
-- mcp-server
Config lands in: ~/.claude.json under mcpServers.arkheia
codex mcp add arkheia \
--env ARKHEIA_API_KEY="$ARKHEIA_API_KEY" \
-- mcp-server
Config lands in: ~/.codex/config.toml under [mcp_servers.arkheia.env]
Note: codex login --api-key is deprecated. Use printenv OPENAI_API_KEY | codex login --with-api-key instead.
gemini mcp add -s user \
-e ARKHEIA_API_KEY="$ARKHEIA_API_KEY" \
arkheia mcp-server
Config lands in: ~/.gemini/settings.json under mcpServers.arkheia
Gotcha: gemini mcp list only shows project-scope servers. If you registered with -s user, verify by reading ~/.gemini/settings.json directly.
Gotcha: Don't use npx -y @arkheia/mcp-server with Gemini — the -y flag gets eaten by Gemini's yargs parser as --yolo. Use the globally-installed mcp-server binary directly.
grok mcp add arkheia \
-t stdio \
-c mcp-server \
-e ARKHEIA_API_KEY="$ARKHEIA_API_KEY"
Config lands in: ~/.grok/settings.json under mcpServers.arkheia (note: env is nested under transport, unlike other CLIs)
# Claude Code — live connection test
claude mcp list
# Codex — shows 'enabled' (not a live check)
codex mcp list
# Grok — best: spawns the server and lists all 9 tools
grok mcp test arkheia
# Gemini — no built-in test; start a session and try the tool
Important: MCP registrations are not hot-reloaded. Restart your CLI session after running mcp add.
| Tool | Description |
|---|---|
arkheia_verify | Score any model response for fabrication risk (LOW/MEDIUM/HIGH) |
arkheia_audit_log | Review your detection history |
run_grok | Call Grok + screen for fabrication |
run_gemini | Call Gemini + screen for fabrication |
run_ollama | Call local Ollama model + screen |
run_together | Call Together AI (Kimi, DeepSeek) + screen |
memory_store | Persistent knowledge graph — upsert entity |
memory_retrieve | Knowledge graph lookup |
memory_relate | Create relationship between entities |
GPT-4o, GPT-5.4, Claude Opus/Sonnet/Haiku, Gemini 2.5/3.0, Grok 4, Llama, Mixtral, CodeLlama, Falcon, Phi4, Kimi K2.5, and more. If your model isn't listed, let us know.
| Plan | Price | Detections |
|---|---|---|
| Free | $0 | 1,500/month |
| Single Contributor | $99/month | Unlimited |
| Professional | $499/month | Unlimited |
| Team | $1,999/month | Unlimited |
Manage your account at arkheia.ai/mcp/account.
| CLI | Config file | Key location |
|---|---|---|
| Claude Code | ~/.claude.json | mcpServers.arkheia.env.ARKHEIA_API_KEY |
| Codex | ~/.codex/config.toml | [mcp_servers.arkheia.env] section |
| Gemini | ~/.gemini/settings.json | mcpServers.arkheia.env.ARKHEIA_API_KEY |
| Grok | ~/.grok/settings.json | mcpServers.arkheia.transport.env.ARKHEIA_API_KEY |
"Python 3.10+ is required but not found" — Install Python 3.12: brew install python@3.12 (macOS) or download from python.org.
"No module named pip" — Your Python installation has broken pip (common with Python 3.14 on macOS). Delete ~/.arkheia/venv and switch to Python 3.12: brew install python@3.12.
Server registered but tools not showing — Restart your CLI session. MCP registrations are not hot-reloaded.
API key rejected — Check for trailing whitespace or \r characters. If your env file was created on Windows, run dos2unix on it. The server will warn about this on startup.
See the GitHub repo for:
Every message is read by the founder.
FAQs
Arkheia MCP Server — Fabrication detection for LLM outputs. Detect hallucination in any model's output with a single tool call.
The npm package @arkheia/mcp-server receives a total of 25 weekly downloads. As such, @arkheia/mcp-server popularity was classified as not popular.
We found that @arkheia/mcp-server demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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