diff --git a/tests/unit/mitm-manager-bypass-json.test.ts b/tests/unit/mitm-manager-bypass-json.test.ts
new file mode 100644
index 0000000000..47dca8a683
--- /dev/null
+++ b/tests/unit/mitm-manager-bypass-json.test.ts
@@ -0,0 +1,104 @@
+/**
+ * Tests for `writeBypassJson()` in src/mitm/manager.ts.
+ *
+ * The function persists user bypass patterns to `<DATA_DIR>/mitm/bypass.json`
+ * which is read by `src/mitm/server.cjs` at boot to drive the CONNECT
+ * handler's bypass routing decision.
+ *
+ * Plan reference: 11-agent-bridge.plan.md §4.6 + master-plan-group-A.md §3.5.
+ */
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const TEST_DATA_DIR = fs.mkdtempSync(
+  path.join(os.tmpdir(), "omniroute-mitm-bypass-json-")
+);
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const core = await import("../../src/lib/db/core.ts");
+const bypassDb = await import("../../src/lib/db/agentBridgeBypass.ts");
+const manager = await import("../../src/mitm/manager.ts");
+
+async function resetStorage() {
+  core.resetDbInstance();
+  for (let attempt = 0; attempt < 10; attempt++) {
+    try {
+      if (fs.existsSync(TEST_DATA_DIR)) {
+        fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+      }
+      break;
+    } catch (error: unknown) {
+      const code = (error as { code?: string } | null)?.code;
+      if ((code === "EBUSY" || code === "EPERM") && attempt < 9) {
+        await new Promise((resolve) => setTimeout(resolve, 50 * (attempt + 1)));
+      } else {
+        throw error;
+      }
+    }
+  }
+  fs.mkdirSync(TEST_DATA_DIR, { recursive: true });
+}
+
+test.beforeEach(async () => {
+  await resetStorage();
+});
+
+test.after(async () => {
+  core.resetDbInstance();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+});
+
+test("writeBypassJson — creates mitm/ dir and writes JSON file", () => {
+  manager.writeBypassJson(["custom.example.com"]);
+  const file = path.join(TEST_DATA_DIR, "mitm", "bypass.json");
+  assert.ok(fs.existsSync(file), "bypass.json must exist after write");
+  const payload = JSON.parse(fs.readFileSync(file, "utf-8"));
+  assert.equal(payload.version, 1);
+  assert.ok(typeof payload.generatedAt === "string");
+  assert.deepEqual(payload.patterns, ["custom.example.com"]);
+});
+
+test("writeBypassJson — empty array writes empty patterns", () => {
+  manager.writeBypassJson([]);
+  const file = path.join(TEST_DATA_DIR, "mitm", "bypass.json");
+  const payload = JSON.parse(fs.readFileSync(file, "utf-8"));
+  assert.deepEqual(payload.patterns, []);
+});
+
+test("writeBypassJson — pulls from DB when no patterns argument passed", () => {
+  // Seed user patterns via the DB module.
+  bypassDb.replaceUserBypassPatterns(["*.from-db.example.com", "literal.com"]);
+  manager.writeBypassJson();
+  const file = path.join(TEST_DATA_DIR, "mitm", "bypass.json");
+  const payload = JSON.parse(fs.readFileSync(file, "utf-8"));
+  assert.deepEqual(
+    payload.patterns.sort(),
+    ["*.from-db.example.com", "literal.com"].sort()
+  );
+});
+
+test("writeBypassJson — does NOT write default patterns (those live in server.cjs)", () => {
+  // Seed defaults via the DB module — these should NOT appear in the JSON.
+  bypassDb.seedDefaultBypassPatterns([
+    "*.bank.test",
+    "*.gov.test",
+    "okta.com",
+    "auth0.com",
+  ]);
+  manager.writeBypassJson();
+  const file = path.join(TEST_DATA_DIR, "mitm", "bypass.json");
+  const payload = JSON.parse(fs.readFileSync(file, "utf-8"));
+  // No user patterns were set → user-only output is empty.
+  assert.deepEqual(payload.patterns, []);
+});
+
+test("writeBypassJson — JSON is well-formed and overwrites previous file", () => {
+  manager.writeBypassJson(["first.com"]);
+  manager.writeBypassJson(["second.com", "third.com"]);
+  const file = path.join(TEST_DATA_DIR, "mitm", "bypass.json");
+  const payload = JSON.parse(fs.readFileSync(file, "utf-8"));
+  assert.deepEqual(payload.patterns, ["second.com", "third.com"]);
+});
diff --git a/tests/unit/mitm-server-connect.test.ts b/tests/unit/mitm-server-connect.test.ts
new file mode 100644
index 0000000000..bf3307ff2d
--- /dev/null
+++ b/tests/unit/mitm-server-connect.test.ts
@@ -0,0 +1,275 @@
+/**
+ * Tests for the bypass / passthrough / target routing primitives used by
+ * the CJS proxy in `src/mitm/server.cjs`.
+ *
+ * The CJS proxy itself cannot be required in tests (it spawns a TLS server
+ * and exits when ROUTER_API_KEY is missing). Instead, we exercise the
+ * `_internal/bypass.cjs` shim that `server.cjs` depends on. That shim
+ * carries all the routing logic — `server.cjs` is now a thin wiring layer
+ * around it.
+ *
+ * Plan reference:
+ *   - 11-agent-bridge.plan.md §4.6
+ *   - master-plan-group-A.md §3.5 / §12 #16
+ */
+import test from "node:test";
+import assert from "node:assert/strict";
+import { createRequire } from "node:module";
+
+const requireCjs = createRequire(import.meta.url);
+const shim = requireCjs("../../src/mitm/_internal/bypass.cjs") as {
+  DEFAULT_BYPASS_PATTERNS: RegExp[];
+  bypassGlobMatch: (h: string, p: string) => boolean;
+  routeBypass: (
+    h: string,
+    targetHosts: Set<string> | string[] | undefined,
+    userPatterns: string[]
+  ) => "bypass" | "target" | "passthrough";
+  parseBypassJson: (raw: string) => string[];
+};
+
+const TARGETS = new Set([
+  "daily-cloudcode-pa.googleapis.com",
+  "api.githubcopilot.com",
+]);
+
+test("DEFAULT_BYPASS_PATTERNS — at least the 4 mandatory regexes", () => {
+  assert.ok(shim.DEFAULT_BYPASS_PATTERNS.length >= 4);
+  for (const re of shim.DEFAULT_BYPASS_PATTERNS) {
+    assert.ok(re instanceof RegExp);
+  }
+});
+
+test("routeBypass — default bank pattern → bypass", () => {
+  assert.equal(shim.routeBypass("my.bank.example", TARGETS, []), "bypass");
+  assert.equal(shim.routeBypass("secure.bank.com", TARGETS, []), "bypass");
+});
+
+test("routeBypass — default gov pattern → bypass", () => {
+  assert.equal(shim.routeBypass("portal.gov.br", TARGETS, []), "bypass");
+  assert.equal(shim.routeBypass("tax.gov", TARGETS, []), "bypass");
+});
+
+test("routeBypass — default okta pattern → bypass", () => {
+  assert.equal(shim.routeBypass("mycorp.okta.com", TARGETS, []), "bypass");
+  assert.equal(shim.routeBypass("okta.com", TARGETS, []), "bypass");
+});
+
+test("routeBypass — default auth0 pattern → bypass", () => {
+  assert.equal(shim.routeBypass("myapp.auth0.com", TARGETS, []), "bypass");
+});
+
+test("routeBypass — bypass beats target match (precedence)", () => {
+  // Hypothetical: user has an okta-hosted Copilot account. Bypass wins.
+  const targets = new Set(["my.okta.com"]);
+  assert.equal(shim.routeBypass("my.okta.com", targets, []), "bypass");
+});
+
+test("routeBypass — known target hostname → target", () => {
+  assert.equal(
+    shim.routeBypass("daily-cloudcode-pa.googleapis.com", TARGETS, []),
+    "target"
+  );
+  assert.equal(shim.routeBypass("api.githubcopilot.com", TARGETS, []), "target");
+});
+
+test("routeBypass — unknown hostname → passthrough", () => {
+  assert.equal(shim.routeBypass("example.com", TARGETS, []), "passthrough");
+  assert.equal(shim.routeBypass("api.openai.com", TARGETS, []), "passthrough");
+});
+
+test("routeBypass — user glob pattern → bypass", () => {
+  const userPatterns = ["*.internal.example.com"];
+  assert.equal(
+    shim.routeBypass("admin.internal.example.com", TARGETS, userPatterns),
+    "bypass"
+  );
+  assert.equal(
+    shim.routeBypass("external.example.com", TARGETS, userPatterns),
+    "passthrough"
+  );
+});
+
+test("routeBypass — empty hostname → passthrough", () => {
+  assert.equal(shim.routeBypass("", TARGETS, []), "passthrough");
+  assert.equal(
+    shim.routeBypass(undefined as unknown as string, TARGETS, []),
+    "passthrough"
+  );
+});
+
+test("routeBypass — targetHosts may be an array (not just Set)", () => {
+  const targetsArr = [
+    "daily-cloudcode-pa.googleapis.com",
+    "api.githubcopilot.com",
+  ];
+  assert.equal(
+    shim.routeBypass("api.githubcopilot.com", targetsArr, []),
+    "target"
+  );
+  assert.equal(shim.routeBypass("example.com", targetsArr, []), "passthrough");
+});
+
+test("routeBypass — case-insensitive on hostname", () => {
+  assert.equal(shim.routeBypass("MyApp.Okta.COM", TARGETS, []), "bypass");
+  assert.equal(
+    shim.routeBypass(
+      "DAILY-cloudcode-pa.googleapis.com".toLowerCase(),
+      TARGETS,
+      []
+    ),
+    "target"
+  );
+});
+
+test("bypassGlobMatch — exact match (no wildcard)", () => {
+  assert.ok(shim.bypassGlobMatch("api.openai.com", "api.openai.com"));
+  assert.ok(!shim.bypassGlobMatch("api.openai.com", "api.anthropic.com"));
+});
+
+test("bypassGlobMatch — single wildcard at start", () => {
+  assert.ok(shim.bypassGlobMatch("foo.example.com", "*.example.com"));
+  assert.ok(shim.bypassGlobMatch("bar.example.com", "*.example.com"));
+  assert.ok(!shim.bypassGlobMatch("example.org", "*.example.com"));
+});
+
+test("bypassGlobMatch — wildcard at end", () => {
+  assert.ok(shim.bypassGlobMatch("api.example.com", "api.*"));
+  assert.ok(!shim.bypassGlobMatch("svc.example.com", "api.*"));
+});
+
+test("bypassGlobMatch — too many wildcards → rejected", () => {
+  // 10 wildcards → segments.length === 11, exceeds the cap.
+  const pat = "a*b*c*d*e*f*g*h*i*j*k";
+  assert.equal(shim.bypassGlobMatch("abcdefghijk", pat), false);
+});
+
+test("bypassGlobMatch — case-insensitive", () => {
+  assert.ok(shim.bypassGlobMatch("FOO.EXAMPLE.COM", "*.example.com"));
+});
+
+test("bypassGlobMatch — does not throw on regex-special chars in pattern", () => {
+  // No regex compilation happens — the helper is a linear string walk.
+  assert.doesNotThrow(() => shim.bypassGlobMatch("test.com", "(invalid["));
+});
+
+test("parseBypassJson — valid JSON with patterns array", () => {
+  const raw = JSON.stringify({
+    version: 1,
+    patterns: ["*.internal.example.com", "Custom.Host.COM"],
+  });
+  const parsed = shim.parseBypassJson(raw);
+  assert.deepEqual(parsed, ["*.internal.example.com", "custom.host.com"]);
+});
+
+test("parseBypassJson — empty input → []", () => {
+  assert.deepEqual(shim.parseBypassJson(""), []);
+});
+
+test("parseBypassJson — malformed JSON → []", () => {
+  assert.deepEqual(shim.parseBypassJson("not json"), []);
+});
+
+test("parseBypassJson — missing patterns property → []", () => {
+  assert.deepEqual(shim.parseBypassJson(JSON.stringify({ version: 1 })), []);
+});
+
+test("parseBypassJson — patterns not an array → []", () => {
+  assert.deepEqual(
+    shim.parseBypassJson(JSON.stringify({ patterns: "foo" })),
+    []
+  );
+});
+
+test("parseBypassJson — filters out non-string and empty entries", () => {
+  const raw = JSON.stringify({
+    patterns: ["valid.com", "", null, 42, "Another.COM"],
+  });
+  const parsed = shim.parseBypassJson(raw);
+  assert.deepEqual(parsed, ["valid.com", "another.com"]);
+});
+
+test("C2 header contract — server.cjs intercept must inject x-omniroute-source and x-omniroute-agent", async () => {
+  // This is a documentation/spec assertion: the exact header names that
+  // server.cjs::intercept must inject per master plan §3.5. If anyone
+  // edits server.cjs to remove or rename them, this test fails and
+  // flags the regression.
+  const fs = await import("node:fs");
+  const path = await import("node:path");
+  const url = await import("node:url");
+  const here = path.dirname(url.fileURLToPath(import.meta.url));
+  const serverPath = path.resolve(here, "../../src/mitm/server.cjs");
+  const src = fs.readFileSync(serverPath, "utf-8");
+  assert.match(
+    src,
+    /"x-omniroute-source":\s*"agent-bridge"/,
+    'server.cjs must inject "x-omniroute-source: agent-bridge"'
+  );
+  assert.match(
+    src,
+    /"x-omniroute-agent":\s*agentId/,
+    'server.cjs must inject "x-omniroute-agent: <id>" from the host→agent map'
+  );
+  // Antigravity non-regression: the historical host must still resolve to
+  // the antigravity agent id, so the existing flow continues to work.
+  assert.match(
+    src,
+    /TARGET_HOST_AGENT\.set\(lower,\s*id\)/,
+    "server.cjs must populate TARGET_HOST_AGENT from targets.json"
+  );
+  assert.match(
+    src,
+    /TARGET_HOST_AGENT\.set\(h,\s*"antigravity"\)/,
+    "server.cjs must seed antigravity baseline in TARGET_HOST_AGENT"
+  );
+});
+
+test("Hard Rule #12 — server.cjs intercept error path uses sanitizeErrorMessage", async () => {
+  // Spec assertion: error responses must NOT leak raw err.message.
+  const fs = await import("node:fs");
+  const path = await import("node:path");
+  const url = await import("node:url");
+  const here = path.dirname(url.fileURLToPath(import.meta.url));
+  const serverPath = path.resolve(here, "../../src/mitm/server.cjs");
+  const src = fs.readFileSync(serverPath, "utf-8");
+  // sanitizeErrorMessage must wrap the error body.
+  assert.match(
+    src,
+    /sanitizeErrorMessage\(error\s*&&\s*error\.message\)/,
+    "intercept() error path must route through sanitizeErrorMessage()"
+  );
+  // The historical raw-leak pattern must be gone from the error body literal.
+  const errorBodyRegion = src.match(
+    /res\.end\(\s*JSON\.stringify\(\{\s*error[\s\S]*?type:\s*"mitm_error"[\s\S]*?\}\)\s*\)/
+  );
+  assert.ok(errorBodyRegion, "intercept() must build a JSON error body");
+  assert.doesNotMatch(
+    errorBodyRegion[0],
+    /message:\s*error\.message[^a-zA-Z_]/,
+    "intercept() error body must not contain raw error.message"
+  );
+});
+
+test("C1 contract — server.cjs registers a CONNECT handler", async () => {
+  const fs = await import("node:fs");
+  const path = await import("node:path");
+  const url = await import("node:url");
+  const here = path.dirname(url.fileURLToPath(import.meta.url));
+  const serverPath = path.resolve(here, "../../src/mitm/server.cjs");
+  const src = fs.readFileSync(serverPath, "utf-8");
+  assert.match(
+    src,
+    /server\.on\(\s*"connect"/,
+    "server.cjs must register a CONNECT handler"
+  );
+  assert.match(
+    src,
+    /net\.connect\(/,
+    "server.cjs must dial upstream via net.connect for bypass/passthrough"
+  );
+  assert.match(
+    src,
+    /HTTP\/1\.1\s+200\s+Connection Established/,
+    "server.cjs CONNECT path must reply with 200 Connection Established"
+  );
+});