diff --git a/.github/workflows/typescript.yml b/.github/workflows/typescript.yml
new file mode 100644
index 0000000..5ffffa7
--- /dev/null
+++ b/.github/workflows/typescript.yml
@@ -0,0 +1,35 @@
+name: typescript
+on:
+  push:
+    branches: [main]
+  pull_request:
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    env:
+      FSC_SKIP_DOCKER_TESTS: "1"
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0 # the co-change coupling tests read the repository's own git history
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+      - name: git identity (tests create commits)
+        run: |
+          git config --global user.name ci
+          git config --global user.email ci@example.com
+          git config --global init.defaultBranch main
+      # The tree-sitter native build (node-gyp) fails on current Node, locally and on the runner,
+      # and nothing under src/ or test/ imports it.
+      - run: bun install --frozen-lockfile --ignore-scripts
+      - name: typecheck
+        run: bun run typecheck
+      - name: tests
+        working-directory: packages/core
+        run: bun run test
+      - name: golden fixtures are in sync with the TypeScript reference
+        run: |
+          bun script/gen-golden.ts
+          bun script/gen-merge-golden.ts
+          git diff --exit-code -- crates/*/tests/golden
diff --git a/packages/core/test/codeCommitterReportVisualization.test.ts b/packages/core/test/codeCommitterReportVisualization.test.ts
index cec7220..eaec92b 100644
--- a/packages/core/test/codeCommitterReportVisualization.test.ts
+++ b/packages/core/test/codeCommitterReportVisualization.test.ts
@@ -1,8 +1,16 @@
-import { describe, it, expect, mock, beforeEach, afterEach } from "bun:test";
+import { describe, it, expect, mock, beforeEach, afterEach, afterAll } from "bun:test";
+import * as realChildProcess from "child_process";
 import { CodeCommitter } from "../src/codeCommitter";
 import type { TaskResult } from "../src/task";
 import { TaskStatus } from "../src/task";
 
+// mock.module() replaces the module for the whole process and is not undone by mock.restore().
+// Without this, every test file that runs after this one sees execSync() === 'abc123def456'.
+const originalChildProcess = { ...realChildProcess };
+afterAll(() => {
+    mock.module('child_process', () => originalChildProcess);
+});
+
 describe('CodeCommitter Beautiful Report Visualization Demo', () => {
     let mockTaskResults: TaskResult[];
 
diff --git a/packages/core/test/copyFilesToContainer.test.ts b/packages/core/test/copyFilesToContainer.test.ts
index 6fe8386..deeffb9 100644
--- a/packages/core/test/copyFilesToContainer.test.ts
+++ b/packages/core/test/copyFilesToContainer.test.ts
@@ -3,12 +3,7 @@ import { spawnSync } from "bun";
 import { DockerInstance } from "../src/dockerInstance";
 import { RunStatus } from "../src/taskExecutor";
 
-const dockerAvailable = (() => {
-  try {
-    const r = spawnSync({ cmd: ["docker", "info"], timeout: 5000 });
-    return r.exitCode === 0;
-  } catch { return false; }
-})();
+import { dockerAvailable } from "./helpers/docker";
 
 const testDocker = test.skipIf(!dockerAvailable);
 
diff --git a/packages/core/test/dockerInstance.test.ts b/packages/core/test/dockerInstance.test.ts
index a3ebcee..87288b8 100644
--- a/packages/core/test/dockerInstance.test.ts
+++ b/packages/core/test/dockerInstance.test.ts
@@ -2,12 +2,7 @@ import { expect, test, describe } from "bun:test";
 import { spawnSync } from "bun";
 import { DockerInstance, DockerRunStatus } from "../src/dockerInstance";
 
-const dockerAvailable = (() => {
-  try {
-    const r = spawnSync({ cmd: ["docker", "info"], timeout: 5000 });
-    return r.exitCode === 0;
-  } catch { return false; }
-})();
+import { dockerAvailable } from "./helpers/docker";
 
 const testDocker = test.skipIf(!dockerAvailable);
 
diff --git a/packages/core/test/dockerInstanceFileRead.test.ts b/packages/core/test/dockerInstanceFileRead.test.ts
index cebe925..6017f2a 100644
--- a/packages/core/test/dockerInstanceFileRead.test.ts
+++ b/packages/core/test/dockerInstanceFileRead.test.ts
@@ -2,12 +2,7 @@ import { expect, test, describe } from "bun:test";
 import { spawnSync } from "bun";
 import { DockerInstance } from "../src/dockerInstance";
 
-const dockerAvailable = (() => {
-  try {
-    const r = spawnSync({ cmd: ["docker", "info"], timeout: 5000 });
-    return r.exitCode === 0;
-  } catch { return false; }
-})();
+import { dockerAvailable } from "./helpers/docker";
 
 const testDocker = test.skipIf(!dockerAvailable);
 
diff --git a/packages/core/test/helpers/docker.ts b/packages/core/test/helpers/docker.ts
new file mode 100644
index 0000000..f02216a
--- /dev/null
+++ b/packages/core/test/helpers/docker.ts
@@ -0,0 +1,14 @@
+import { spawnSync } from "bun";
+
+/**
+ * True when Docker integration tests can run. Set FSC_SKIP_DOCKER_TESTS=1 to skip them even if
+ * Docker is installed (CI does this: the native pipeline does not need Docker).
+ */
+export const dockerAvailable: boolean = (() => {
+  if (process.env.FSC_SKIP_DOCKER_TESTS === "1") return false;
+  try {
+    return spawnSync({ cmd: ["docker", "info"], timeout: 5000 }).exitCode === 0;
+  } catch {
+    return false;
+  }
+})();
diff --git a/packages/core/test/runCommandAsync.test.ts b/packages/core/test/runCommandAsync.test.ts
index 8dd153f..17dc9d7 100644
--- a/packages/core/test/runCommandAsync.test.ts
+++ b/packages/core/test/runCommandAsync.test.ts
@@ -2,12 +2,7 @@ import { expect, test, describe, beforeAll, afterAll, jest } from 'bun:test';
 import { spawnSync } from "bun";
 import { DockerInstance, DockerRunStatus } from "../src/dockerInstance";
 
-const dockerAvailable = (() => {
-  try {
-    const r = spawnSync({ cmd: ["docker", "info"], timeout: 5000 });
-    return r.exitCode === 0;
-  } catch { return false; }
-})();
+import { dockerAvailable } from "./helpers/docker";
 
 const describeDocker = dockerAvailable ? describe : describe.skip;
 
diff --git a/packages/core/test/salacia/coupling.test.ts b/packages/core/test/salacia/coupling.test.ts
index 34909c5..e180580 100644
--- a/packages/core/test/salacia/coupling.test.ts
+++ b/packages/core/test/salacia/coupling.test.ts
@@ -1,7 +1,10 @@
 import { describe, test, expect } from "bun:test";
 import { getCoChangedFiles, expandWithCoupling } from "../../src/salacia/coupling";
 
-const REPO = "D:/projects/full-self-coding";
+import { resolve } from "path";
+
+// The repository this test file lives in (test/salacia -> packages/core -> packages -> repo root).
+const REPO = resolve(import.meta.dir, "..", "..", "..", "..");
 
 describe("getCoChangedFiles", () => {
   test("returns co-changed files for scheduler.ts", () => {
diff --git a/packages/core/test/salacia/replay-real-commits.test.ts b/packages/core/test/salacia/replay-real-commits.test.ts
index 5e1f3c7..f40c909 100644
--- a/packages/core/test/salacia/replay-real-commits.test.ts
+++ b/packages/core/test/salacia/replay-real-commits.test.ts
@@ -1,10 +1,12 @@
 import { describe, test, expect } from "bun:test";
+import { resolve } from "path";
 import { gitExec } from "../../src/execution/gitExec";
 import { generateContract } from "../../src/salacia/contract";
 import { detectDrift, isFatalDrift, exceedsThreshold } from "../../src/salacia/drift";
 import type { Task } from "../../src/task";
 
-const REPO = "D:/projects/full-self-coding";
+// The repository this test file lives in (test/salacia -> packages/core -> packages -> repo root).
+const REPO = resolve(import.meta.dir, "..", "..", "..", "..");
 
 function getRecentCommits(n: number): Array<{ hash: string; message: string; files: string[] }> {
   const log = gitExec(["log", "--oneline", `-${n}`], REPO);
diff --git a/packages/core/test/taskSolverClaudeCode.test.ts b/packages/core/test/taskSolverClaudeCode.test.ts
index 78a6d27..3d002cf 100644
--- a/packages/core/test/taskSolverClaudeCode.test.ts
+++ b/packages/core/test/taskSolverClaudeCode.test.ts
@@ -8,12 +8,7 @@ import { WorkStyle } from "../src/workStyle";
 import {CLAUDE_CODE_API_KEY, CLAUDE_CODE_API_URL} from "./apiKeySetup";
 import { spawnSync } from "bun";
 
-const dockerAvailable = (() => {
-  try {
-    const r = spawnSync({ cmd: ["docker", "info"], timeout: 5000 });
-    return r.exitCode === 0;
-  } catch { return false; }
-})();
+import { dockerAvailable } from "./helpers/docker";
 
 const testDocker = test.skipIf(!dockerAvailable || !process.env.ANTHROPIC_API_KEY);
 
diff --git a/packages/core/test/taskSolverGemini.test.ts b/packages/core/test/taskSolverGemini.test.ts
index b4ec37f..c66aa97 100644
--- a/packages/core/test/taskSolverGemini.test.ts
+++ b/packages/core/test/taskSolverGemini.test.ts
@@ -8,12 +8,7 @@ import { WorkStyle } from "../src/workStyle";
 import {GEMINI_API_KEY} from "./apiKeySetup";
 import { spawnSync } from "bun";
 
-const dockerAvailable = (() => {
-  try {
-    const r = spawnSync({ cmd: ["docker", "info"], timeout: 5000 });
-    return r.exitCode === 0;
-  } catch { return false; }
-})();
+import { dockerAvailable } from "./helpers/docker";
 
 const testDocker = test.skipIf(!dockerAvailable || !process.env.GEMINI_API_KEY);