feat(ts-sdk): add trust score persistence

packages/agent-mesh/sdks/typescript/src/trust.ts

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
+import * as fs from 'fs';
 import { AgentIdentity } from './identity';
 import {
   TrustConfig,
@@ -27,15 +28,20 @@ interface AgentTrustState {
  * with configurable decay.
  */
 export class TrustManager {
-  private readonly config: Required<TrustConfig>;
+  private readonly config: Required<Omit<TrustConfig, 'persistPath'>>;
   private readonly agents: Map<string, AgentTrustState> = new Map();
+  private readonly persistPath?: string;
 
   constructor(config?: TrustConfig) {
     this.config = {
       initialScore: config?.initialScore ?? 0.5,
       decayFactor: config?.decayFactor ?? 0.95,
       thresholds: { ...DEFAULT_THRESHOLDS, ...config?.thresholds },
     };
+    this.persistPath = config?.persistPath;
+    if (this.persistPath) {
+      this.loadFromDisk();
+    }
   }
 
   /** Verify a peer agent's identity and return a trust result. */
@@ -83,6 +89,7 @@ export class TrustManager {
     state.successes += 1;
     state.score = Math.min(1, state.score + reward);
     state.lastUpdate = Date.now();
+    this.saveToDisk();
   }
 
   /** Record a failed interaction with an agent. */
@@ -92,6 +99,7 @@ export class TrustManager {
     state.failures += 1;
     state.score = Math.max(0, state.score - penalty);
     state.lastUpdate = Date.now();
+    this.saveToDisk();
   }
 
   // ── Private helpers ──
@@ -133,4 +141,30 @@ export class TrustManager {
     if (total === 0) return this.config.initialScore;
     return Math.round((state.successes / total) * 1000) / 1000;
   }
+
+  private saveToDisk(): void {
+    if (!this.persistPath) return;
+    try {
+      const data: Record<string, AgentTrustState> = {};
+      for (const [key, value] of this.agents) {
+        data[key] = value;
+      }
+      fs.writeFileSync(this.persistPath, JSON.stringify(data), 'utf-8');
+    } catch {
+      // best-effort: ignore write errors
+    }
+  }
+
+  private loadFromDisk(): void {
+    if (!this.persistPath) return;
+    try {
+      const raw = fs.readFileSync(this.persistPath, 'utf-8');
+      const data = JSON.parse(raw) as Record<string, AgentTrustState>;
+      for (const [key, value] of Object.entries(data)) {
+        this.agents.set(key, value);
+      }
+    } catch {
+      // best-effort: ignore missing or corrupt files
+    }
+  }
 }

packages/agent-mesh/sdks/typescript/src/types.ts

@@ -36,6 +36,8 @@ export interface TrustConfig {
     trusted: number;
     verified: number;
   };
+  /** Optional file path for persisting trust scores across restarts */
+  persistPath?: string;
 }
 
 export type TrustTier = 'Untrusted' | 'Provisional' | 'Trusted' | 'Verified';

packages/agent-mesh/sdks/typescript/tests/trust-persistence.test.ts

@@ -0,0 +1,61 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import * as crypto from 'crypto';
+import { TrustManager } from '../src/trust';
+
+function tempFilePath(): string {
+  return path.join(os.tmpdir(), `trust-${crypto.randomUUID()}.json`);
+}
+
+afterEach(() => {
+  // cleanup is best-effort; individual tests also clean up
+});
+
+describe('TrustManager persistence', () => {
+  it('persists scores across instances', () => {
+    const file = tempFilePath();
+    try {
+      const tm1 = new TrustManager({ initialScore: 0.5, persistPath: file });
+      tm1.recordSuccess('agent-a', 0.1);
+      tm1.recordFailure('agent-b', 0.2);
+
+      // Second instance should load persisted state
+      const tm2 = new TrustManager({ initialScore: 0.5, persistPath: file });
+      expect(tm2.getTrustScore('agent-a').overall).toBeGreaterThan(0.5);
+      expect(tm2.getTrustScore('agent-b').overall).toBeLessThan(0.5);
+    } finally {
+      try { fs.unlinkSync(file); } catch { /* ignore */ }
+    }
+  });
+
+  it('handles missing file gracefully', () => {
+    const file = tempFilePath(); // does not exist
+    expect(() => {
+      const tm = new TrustManager({ initialScore: 0.5, persistPath: file });
+      expect(tm.getTrustScore('agent-x').overall).toBe(0.5);
+    }).not.toThrow();
+  });
+
+  it('handles corrupt file gracefully', () => {
+    const file = tempFilePath();
+    try {
+      fs.writeFileSync(file, '<<<not json>>>', 'utf-8');
+      expect(() => {
+        const tm = new TrustManager({ initialScore: 0.5, persistPath: file });
+        expect(tm.getTrustScore('agent-x').overall).toBe(0.5);
+      }).not.toThrow();
+    } finally {
+      try { fs.unlinkSync(file); } catch { /* ignore */ }
+    }
+  });
+
+  it('does not persist when persistPath is not set', () => {
+    const tm = new TrustManager({ initialScore: 0.5 });
+    tm.recordSuccess('agent-a', 0.1);
+    // No error, no file created — just verifying the code path works
+    expect(tm.getTrustScore('agent-a').overall).toBeGreaterThan(0.5);
+  });
+});