diff --git a/codecov.yml b/codecov.yml
index 76dd25a4b..05ee97141 100644
--- a/codecov.yml
+++ b/codecov.yml
@@ -29,8 +29,9 @@ comment:
   layout: "condensed_header, diff, flags, files"
   require_changes: false
 
-# Coverage is collected by vitest (v8) over src/**; mirror its exclusions so the
-# Codecov total matches the local report.
+# Coverage is collected by vitest (v8) over src/**, packages/gittensory-engine/src/**,
+# and packages/gittensory-miner/lib/**; mirror its exclusions so the Codecov total
+# matches the local report.
 ignore:
   - "src/env.d.ts"
   - "apps/**"
diff --git a/test/unit/codecov-policy.test.ts b/test/unit/codecov-policy.test.ts
index 373817946..cd464e092 100644
--- a/test/unit/codecov-policy.test.ts
+++ b/test/unit/codecov-policy.test.ts
@@ -75,6 +75,16 @@ describe("Codecov policy", () => {
     expect(testResultsUploadWith.fail_ci_if_error).toBe(false);
   });
 
+  it("measures miner lib changes for codecov patch coverage (#4864)", () => {
+    const vitestConfig = readFileSync("vitest.config.ts", "utf8");
+    expect(vitestConfig).toMatch(/packages\/gittensory-miner\/lib\/\*\*\/\*\.js/);
+
+    const config = readYaml("codecov.yml");
+    const ignore = config.ignore;
+    if (!Array.isArray(ignore)) throw new Error("codecov.yml ignore must be an array");
+    expect(ignore.some((entry) => typeof entry === "string" && entry.includes("gittensory-miner"))).toBe(false);
+  });
+
   it("uploads fork PR coverage tokenlessly instead of silently skipping it", () => {
     // Fork PRs cannot read secrets.CODECOV_TOKEN. Previously the token-gated upload steps simply
     // excluded forks with no replacement, so codecov/patch had no report to compare against and fell
diff --git a/vitest.config.ts b/vitest.config.ts
index 2df10ca8f..87d6acfa1 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -26,7 +26,12 @@ export default defineConfig({
     ...(junitPath ? { outputFile: { junit: junitPath } } : {}),
     coverage: {
       provider: "v8",
-      include: ["src/**/*.ts", "packages/gittensory-engine/src/**/*.ts", "review-enrichment/src/analyzers/codeowners.ts"],
+      include: [
+        "src/**/*.ts",
+        "packages/gittensory-engine/src/**/*.ts",
+        "packages/gittensory-miner/lib/**/*.js",
+        "review-enrichment/src/analyzers/codeowners.ts",
+      ],
       exclude: ["src/env.d.ts", "apps/**"],
       // Emit lcov for Codecov to compute patch (changed-lines) coverage.
       reporter: ["text", "lcov"],