npm install mcp-trust-guard

import express from 'express';
import { McpGuard } from 'mcp-trust-guard';

const guard = new McpGuard({
  rules: [
    { minTrust: 0,  tools: ['get_*', 'list_*', 'search_*'] },
    { minTrust: 30, tools: ['create_*', 'update_*'] },
    { minTrust: 60, tools: ['delete_*', 'admin_*'] },
  ],
  rateLimit: { window: 60, max: 30 },
  audit: true,
});

const app = express();
app.use(express.json());
app.use('/mcp', guard.middleware());
// ... your MCP server handler

                                    ┌──────────────┐
Request ──→ Extract Identity ──→ Rate Limit ──→ │  Trust Check │ ──→ Rule Match ──→ Allow/Deny
             (header)            (per caller)    │ (AgentScore) │    (tool pattern)
                                                 └──────────────┘

const guard = new McpGuard({
  rules: [
    { minTrust: 0,  tools: ['read_*'] },      // Public — anyone can read
    { minTrust: 20, tools: ['query_*'] },      // Low bar — basic queries
    { minTrust: 40, tools: ['write_*'] },      // Verified agents only
    { minTrust: 70, tools: ['transfer_*'] },   // High trust — financial ops
  ],
  defaultMinTrust: 10, // Tools not matching any rule require score >= 10
});

{ minTrust: 30, tools: ['create_*', 'update_*'] }    // Matches create_user, update_record
{ minTrust: 60, tools: ['admin_*'] }                   // Matches admin_delete, admin_config
{ minTrust: 0,  tools: ['get_status'] }                // Exact match only
{ minTrust: 50, tools: ['*'] }                         // Catch-all

const guard = new McpGuard({
  rateLimit: {
    window: 60,  // 60-second window
    max: 30,     // 30 requests per window per caller
  },
});

const guard = new McpGuard({ audit: true });
// [mcp-guard] ALLOW EmberFoundry → get_status (score: 42, band: MODERATE TRUST) score 42 >= 0 required for get_status
// [mcp-guard] DENY  untrusted-bot → admin_delete (score: 3, band: UNVERIFIED) score 3 < 60 required for admin_delete

const guard = new McpGuard({
  audit: (entry) => {
    db.insert('audit_log', entry);
    if (!entry.allowed) alerting.notify(`Blocked ${entry.caller} from ${entry.tool}`);
  },
});

const guard = new McpGuard();

const decision = await guard.check('EmberFoundry', 'transfer_funds');
// { allowed: false, reason: 'score 14 < 70 required for transfer_funds', caller: 'EmberFoundry', trustScore: 14, trustBand: 'UNVERIFIED' }

import { McpGuard, TrustProvider, TrustResult } from 'mcp-trust-guard';

const myProvider: TrustProvider = {
  async check(name: string): Promise<TrustResult> {
    const score = await myDatabase.getAgentScore(name);
    return { score, band: score > 50 ? 'TRUSTED' : 'UNTRUSTED', name };
  },
};

const guard = new McpGuard({ provider: myProvider });

const protectedHandler = guard.wrap(mcpHandler);
http.createServer(protectedHandler).listen(3000);

curl -X POST http://localhost:3000/mcp \
  -H "Content-Type: application/json" \
  -H "x-agent-name: MyAgent" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"get_data"}}'

const guard = new McpGuard({ identityHeader: 'authorization' });

const guard = new McpGuard({
  abuseCheck: true,                // Enable abuse database checks
  abuseBlockLevel: 'CAUTION',      // Block at MONITOR, CAUTION, or BLOCK level
  rules: [
    { minTrust: 0, tools: ['get_*'] },
    { minTrust: 30, tools: ['write_*'] },
  ],
  audit: true,
});

[mcp-guard] DENY bad-agent → write_file (score: -1, band: ABUSE_REPORTED)
  agent reported in KYA abuse database: prompt_injection (1 reports, severity: high)