diff --git a/src/runtime/evidence/runtime-evidence.service.ts b/src/runtime/evidence/runtime-evidence.service.ts
new file mode 100644
index 0000000..a02ce74
--- /dev/null
+++ b/src/runtime/evidence/runtime-evidence.service.ts
@@ -0,0 +1,75 @@
+import { Injectable } from '@nestjs/common';
+import {
+  RuntimeEvidenceCleanupResult,
+  RuntimeEvidenceInput,
+  RuntimeEvidenceRecord,
+} from './runtime-evidence.types';
+
+const REDACTED_VALUE = '<redacted>';
+const SENSITIVE_KEY_PATTERN =
+  /password|secret|token|authorization|cookie|privateKey|sshKey|ticket|randstr|replyText/i;
+
+@Injectable()
+export class RuntimeEvidenceService {
+  createRecord(input: RuntimeEvidenceInput): RuntimeEvidenceRecord {
+    const startedAt = input.startedAt ?? new Date();
+    const endedAt = input.endedAt ?? new Date();
+
+    return {
+      ...input,
+      startedAt,
+      endedAt,
+      durationMs: Math.max(0, endedAt.getTime() - startedAt.getTime()),
+      schemaVersion: 1,
+      details: this.sanitizeRecord(input.details),
+      cleanup: this.sanitizeCleanup(input.cleanup),
+    };
+  }
+
+  private sanitizeCleanup(
+    cleanup?: RuntimeEvidenceCleanupResult,
+  ): RuntimeEvidenceCleanupResult | undefined {
+    if (!cleanup) return undefined;
+
+    return {
+      ...cleanup,
+      details: this.sanitizeRecord(cleanup.details),
+    };
+  }
+
+  private sanitizeRecord(
+    value?: Record<string, unknown>,
+  ): Record<string, unknown> | undefined {
+    if (!value) return undefined;
+    return this.sanitizeValue(value) as Record<string, unknown>;
+  }
+
+  private sanitizeValue(value: unknown): unknown {
+    if (value instanceof Date) return value;
+    if (Array.isArray(value)) {
+      return value.map((item) => this.sanitizeValue(item));
+    }
+    if (this.isPlainRecord(value)) {
+      return Object.fromEntries(
+        Object.entries(value).map(([key, entry]) => [
+          key,
+          this.isSensitiveKey(key) ? REDACTED_VALUE : this.sanitizeValue(entry),
+        ]),
+      );
+    }
+    return value;
+  }
+
+  private isPlainRecord(value: unknown): value is Record<string, unknown> {
+    return (
+      typeof value === 'object' &&
+      value !== null &&
+      !Array.isArray(value) &&
+      !(value instanceof Date)
+    );
+  }
+
+  private isSensitiveKey(key: string) {
+    return SENSITIVE_KEY_PATTERN.test(key);
+  }
+}
diff --git a/src/runtime/evidence/runtime-evidence.types.ts b/src/runtime/evidence/runtime-evidence.types.ts
new file mode 100644
index 0000000..e248a88
--- /dev/null
+++ b/src/runtime/evidence/runtime-evidence.types.ts
@@ -0,0 +1,42 @@
+import type { RuntimeClassifiedError } from '../errors/runtime-error.types';
+
+export type RuntimeEvidenceStatus =
+  | 'passed'
+  | 'failed'
+  | 'blocked'
+  | 'skipped';
+
+export interface RuntimeEvidenceCleanupResult {
+  status: RuntimeEvidenceStatus;
+  message: string;
+  details?: Record<string, unknown>;
+}
+
+export interface RuntimeEvidenceAssertion {
+  name: string;
+  passed: boolean;
+  message: string;
+}
+
+export interface RuntimeEvidenceInput {
+  title: string;
+  taskType: string;
+  project: string;
+  environment: string;
+  operation: string;
+  target?: string;
+  status: RuntimeEvidenceStatus;
+  startedAt?: Date;
+  endedAt?: Date;
+  details?: Record<string, unknown>;
+  assertions?: RuntimeEvidenceAssertion[];
+  cleanup?: RuntimeEvidenceCleanupResult;
+  error?: RuntimeClassifiedError;
+}
+
+export interface RuntimeEvidenceRecord extends RuntimeEvidenceInput {
+  startedAt: Date;
+  endedAt: Date;
+  durationMs: number;
+  schemaVersion: 1;
+}
diff --git a/test/runtime/runtime-evidence.service.spec.ts b/test/runtime/runtime-evidence.service.spec.ts
new file mode 100644
index 0000000..0ab9dd7
--- /dev/null
+++ b/test/runtime/runtime-evidence.service.spec.ts
@@ -0,0 +1,112 @@
+import { RuntimeEvidenceService } from '../../src/runtime/evidence/runtime-evidence.service';
+
+describe('RuntimeEvidenceService', () => {
+  it('creates records with explicit timing, duration, and schema version', () => {
+    const service = new RuntimeEvidenceService();
+    const startedAt = new Date('2026-06-13T00:00:00.000Z');
+    const endedAt = new Date('2026-06-13T00:00:01.250Z');
+
+    const record = service.createRecord({
+      title: 'runtime config smoke',
+      taskType: 'backend',
+      project: 'kt-template-online-api',
+      environment: 'local',
+      operation: 'runtime-config',
+      status: 'passed',
+      startedAt,
+      endedAt,
+    });
+
+    expect(record.startedAt).toBe(startedAt);
+    expect(record.endedAt).toBe(endedAt);
+    expect(record.durationMs).toBe(1250);
+    expect(record.schemaVersion).toBe(1);
+  });
+
+  it('redacts nested sensitive fields in details and cleanup details', () => {
+    const service = new RuntimeEvidenceService();
+
+    const record = service.createRecord({
+      title: 'qqbot captcha smoke',
+      taskType: 'api',
+      project: 'kt-template-online-api',
+      environment: 'local',
+      operation: 'qqbot-login',
+      target: 'account:2637330537',
+      status: 'blocked',
+      details: {
+        username: 'kept-user',
+        password: 1,
+        nested: {
+          token: true,
+          message: 'kept-message',
+          replyText: 'raw-reply-text',
+        },
+      },
+      cleanup: {
+        status: 'failed',
+        message: 'cleanup failed',
+        details: {
+          ticket: 'raw-ticket',
+          randstr: 'raw-randstr',
+          removed: false,
+        },
+      },
+    });
+
+    expect(record.details).toEqual({
+      username: 'kept-user',
+      password: '<redacted>',
+      nested: {
+        token: '<redacted>',
+        message: 'kept-message',
+        replyText: '<redacted>',
+      },
+    });
+    expect(record.cleanup?.details).toEqual({
+      ticket: '<redacted>',
+      randstr: '<redacted>',
+      removed: false,
+    });
+  });
+
+  it('sanitizes arrays and case-insensitive sensitive keys while preserving dates', () => {
+    const service = new RuntimeEvidenceService();
+    const createdAt = new Date('2026-06-13T00:00:00.000Z');
+
+    const record = service.createRecord({
+      title: 'array evidence',
+      taskType: 'backend',
+      project: 'kt-template-online-api',
+      environment: 'local',
+      operation: 'runtime-evidence',
+      status: 'failed',
+      details: {
+        events: [
+          { Authorization: 'Bearer raw', name: 'kept' },
+          { nested: { Cookie: 'session=raw', count: 2 } },
+        ],
+        createdAt,
+      },
+    });
+
+    const details = record.details as {
+      events: Array<Record<string, unknown>>;
+      createdAt: Date;
+    };
+
+    expect(details.createdAt).toBe(createdAt);
+    expect(details.createdAt).toBeInstanceOf(Date);
+    expect(details.events).toHaveLength(2);
+    expect(details.events[0]).toEqual({
+      Authorization: '<redacted>',
+      name: 'kept',
+    });
+    expect(details.events[1]).toEqual({
+      nested: {
+        Cookie: '<redacted>',
+        count: 2,
+      },
+    });
+  });
+});