@yobekasbah/mcp-server

The trust layer for agentic AI — drop into Claude Desktop, Claude Code, Cursor, Cline, or any MCP-compatible host. Govern, sign, and verify every action your agent takes. Every decision gets a verdict + an Ed25519-signed receipt that's verifiable offline, forever.

https://kasbah-api.fly.dev · Get a free API key · Receipt Spec v2

Install

npx -y @yobekasbah/mcp-server

That's it. No global install needed.

1. Get a free API key

https://kasbah-api.fly.dev/v1/auth/signup

You get a key (ksk_…), a workspace, and a generous free tier. The key is required for the governance tools (kasbah_attest, kasbah_check_compliance, kasbah_trace_intent, kasbah_cost_guard).

2. Configure your host

Add to ~/.claude/mcp.json (or mcp.json for Cursor / Cline / your host):

{
  "mcpServers": {
    "kasbah": {
      "command": "npx",
      "args": ["-y", "@yobekasbah/mcp-server"],
      "env": {
        "KASBAH_API":     "https://kasbah-api.fly.dev",
        "KASBAH_API_KEY": "ksk_your_key_here",
        "KASBAH_AGENT":   "my-agent"
      }
    }
  }
}

Local dev? Point KASBAH_API at your own engine instead:

git clone https://github.com/Al-Adnane/Kasbah-Core
cd Kasbah-Core
node packages/api-server/server.js
# → engine on http://127.0.0.1:8788, kid 029e59…

What you get

Seven tools, three jobs.

Trust layer — kasbah_attest · kasbah_verify · kasbah_status · kasbah_export_audit Governance moats — kasbah_check_compliance · kasbah_trace_intent · kasbah_cost_guard

kasbah_attest

Call this before any side-effecting action — file write, shell exec, HTTP request, payment, tool call. Returns a verdict and a signed receipt.

const r = await mcp.call('kasbah_attest', {
  action: 'shell_exec',
  input: 'rm -rf /var/db',
  context: 'cleanup script',
  surface: 'claude-code'
});
// → { verdict: 'DENY', receipt: 'kasbah_receipt:v2:ed25519:…',
//     guidance: 'STOP. Kasbah denied this action. Do not proceed.' }

When verdict === 'DENY', stop. Kasbah caught something the agent shouldn't do. The receipt is your proof.

kasbah_status

Show what Kasbah has done for you. Running totals: $ saved, decisions blocked, PII redactions, top token sinks, latest receipt + verify link, dashboard URLs. Call this anytime to see real value-for-money.

const r = await mcp.call('kasbah_status');
// → {
//     headline: "1,247 decisions signed · 47 blocked · $34.21 saved this session",
//     money:   { saved_this_session_usd: 34.21, top_models_by_cost: [...] },
//     safety:  { blocked: 47, warned: 12, threats_detected: 8, top_sink: {...} },
//     receipts:{ signing_key_id: "029e59…", verify_latest_offline_url: "..." },
//     dashboards: { live_stream: "...", verify_any_receipt: "..." },
//     feedback: "mailto:[email protected]?…"
//   }

kasbah_export_audit

Export a compliance bundle (last N signed decisions) as a tamper-evident JSON archive. Each entry includes its Ed25519 signature + the public key fingerprint. Hand this to your SOC 2 / EU AI Act auditor — they verify it offline, no Kasbah account needed.

const bundle = await mcp.call('kasbah_export_audit', { limit: 1000, verdict: 'DENY' });
// → { bundle_format_version: "kasbah-audit-bundle-v1",
//     signing_public_key: { kid: "029e59…", x: "...", pem: "..." },
//     entries: [{ timestamp, verdict, receipt, receipt_payload, ... }],
//     how_to_verify: "..."
//   }

kasbah_verify

Verify any Kasbah receipt cryptographically. Works offline — only needs the cached public key.

const v = await mcp.call('kasbah_verify', { receipt, payload });
// → { verified: true, keyId: '029e59…', decoded: { … } }

kasbah_check_compliance

Evaluate an action against HIPAA / GDPR / SOC 2 / PCI-DSS rule packs before it runs. Returns a decision with the cited rule.

const c = await mcp.call('kasbah_check_compliance', {
  verb: 'EXPORT', target: 'patient_records', content: 'SSN 123-45-6789'
});
// → { decision: 'DENY', summary: 'DENIED by H-002: SSN/DOB in agent output requires redaction',
//     guidance: 'Blocked by compliance policy — do not proceed.' }

kasbah_trace_intent

Catch distributed, multi-step attacks invisible to single-step scanners — exfiltration pipelines, privilege-escalation chains, cost bombs. Pass the recent steps, one VERB target per line.

const t = await mcp.call('kasbah_trace_intent', {
  steps: 'READ patient_db\nAGGREGATE records\nENCODE base64\nSEND external.evil.com'
});
// → { verdict: 'CRITICAL', summary: 'Data Exfiltration Pipeline (critical) — 100% confidence',
//     guidance: 'Multi-step attack trajectory detected — halt the agent and alert the user.' }

kasbah_cost_guard

Runaway-loop and spend governor. Recommends ALLOW / THROTTLE / BLOCK before an expensive or repeated call.

const g = await mcp.call('kasbah_cost_guard', { agent: 'orchestrator', tool: 'web_search', calls: 8 });
// → { action: 'BLOCK', reason: 'runaway_loop_detected',
//     usage: { band: 'mid', costPerHour: 0.32, tokensPerMin: ... },
//     guidance: 'Stop — runaway loop or budget breach. Do not make this call.' }

Configuration · environment variables

| Var | Default | What it controls | |---|---|---| | KASBAH_API | http://127.0.0.1:8788 | Engine endpoint (use https://kasbah-api.fly.dev for hosted) | | KASBAH_API_KEY | (none) | Required for governance tools. Free key at get a free key | | KASBAH_AGENT | mcp-agent | Identifier in audit receipts | | KASBAH_VERIFY_BASE | https://kasbah-api.fly.dev/demo/verify | Public verifier URL stamped into receipts | | KASBAH_NO_TELEMETRY | (unset) | Set to 1 to opt out of the anonymous boot-count ping to /_pulse. We collect zero prompts, payloads, or PII — only that the MCP started. |

Got feedback? Found a bug?

Email [email protected] · Issues: github.com/Al-Adnane/Kasbah-Core/issues

Every kasbah_status response includes a one-click feedback mailto: so you can tell us what's working and what isn't, right from your IDE.

Verify it works

node -e "
const { spawn } = require('child_process');
const p = spawn('npx', ['@yobekasbah/mcp-server'], { stdio: ['pipe', 'pipe', 'inherit'] });
p.stdin.write(JSON.stringify({ jsonrpc:'2.0', id:1, method:'initialize', params:{} }) + '\n');
p.stdout.on('data', d => { console.log(d.toString()); p.kill(); });
"
# → { jsonrpc:'2.0', id:1, result: { protocolVersion:'2024-11-05',
#     capabilities:{tools:{}}, serverInfo:{name:'kasbah', version:'3.0.0'} } }

The receipt format

Every receipt this server returns is Ed25519-signed by the engine following Receipt Spec v2. Anyone with the engine's public key can verify it offline:

curl https://kasbah-api.fly.dev/.well-known/kasbah-keys.json
# → { "keys": [{ "kid": "029e59…", "alg": "EdDSA", "crv": "Ed25519", "x": "…" }] }

The format is open, the verifier is open (standalone WebCrypto, 200 lines), and your receipts will verify as long as the spec lives — even if Kasbah ceased to exist tomorrow.

Production Notes

Signing Key Persistence

The engine generates an Ed25519 signing key on first boot (data/engine-key.priv.pem). This key is the root of trust for all receipts. If the container is recreated without a volume mount, old receipts become unverifiable.

For production deployments, mount a persistent volume:

# Docker
docker run -v kasbah-data:/app/packages/api-server/data ...

# Fly.io
fly volumes create kasbah_data --size 1

Engine Availability

The governance tools call the Kasbah engine at the configured KASBAH_API URL. If the engine is unreachable, kasbah_attest still signs the action but marks it governed: false (fail-open on availability, never on a real DENY). The other governance tools surface a clear error. For production, use the hosted endpoint https://kasbah-api.fly.dev or run the engine on a high-availability host.

License

MIT.