diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0062701..13c6b04 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -35,6 +35,15 @@
   boolean aliases (`--json`/`--csv`/`--md`/`--xml`/`--files`) still work but are
   no longer in `--help`; prefer `--format`.
 
+### Fixes
+
+- Launcher: source-mode runner selection now prefers Node + tsx over Bun when
+  both `package-lock.json` and `bun.lock` are present in the package root,
+  mirroring the dist-mode "npm priority" rule. Fixes pnpm-global installs that
+  copy the entire working tree (including `.git` and `bun.lock`) into the
+  install dir and previously routed through Bun, causing ABI mismatches with
+  the Node-built `better-sqlite3` / `sqlite-vec` native modules.
+
 ### Docs
 
 - qmd skill: emphasize reading line ranges with `get`'s built-in
diff --git a/bin/qmd b/bin/qmd
index a5d583f..b76d20e 100755
--- a/bin/qmd
+++ b/bin/qmd
@@ -43,22 +43,52 @@ function hasBun() {
 // dist/ is often ignored and can be stale after git reset or branch switches.
 // Prefer source mode only for checkouts so ./bin/qmd reflects the checked-out
 // source without changing packaged/runtime behavior.
+//
+// Critical: source-mode detection must NOT trigger when a package manager
+// installed us. `pnpm install -g .` (and `npm install -g .`) copy the entire
+// working tree — including .git/, bun.lock, package-lock.json, src/, and even
+// node_modules/ — into <prefix>/node_modules/@tobilu/qmd/, so .git and a
+// lockfile being present is not a reliable "this is a working tree" signal.
+// What IS reliable: a package-manager install always lands the package
+// directory inside a `node_modules/` segment; a bare working-tree checkout
+// (with `bun link` or a direct path invocation) does not. Gate source mode
+// on that. Allow QMD_SOURCE_MODE=1 / =0 as an explicit override for the
+// rare case where the heuristic disagrees with the user.
+const sourceOverride = process.env.QMD_SOURCE_MODE;
+const looksInstalled = pkgDir.split("/").includes("node_modules");
+const sourceAllowed = sourceOverride === "1"
+  || (sourceOverride !== "0" && !looksInstalled);
+
 let useSourceMode = false;
 let sourceRunner = null;
 let sourceArgs = [];
 
-if (existsSync(resolve(pkgDir, ".git")) && existsSync(tsEntry)) {
-  if (existsSync(resolve(pkgDir, "bun.lock")) || existsSync(resolve(pkgDir, "bun.lockb"))) {
-    if (hasBun()) {
-      useSourceMode = true;
-      sourceRunner = "bun";
-      sourceArgs = [tsEntry, ...process.argv.slice(2)];
-    }
-  }
-  if (!useSourceMode && existsSync(resolve(pkgDir, "node_modules/tsx/dist/cli.mjs"))) {
+if (sourceAllowed && existsSync(resolve(pkgDir, ".git")) && existsSync(tsEntry)) {
+  // Lockfile-driven runner selection — mirror the dist-mode logic below so
+  // source mode picks the same runtime the user's deps were installed for.
+  // package-lock.json wins over bun.lock when both are present: pnpm/npm
+  // installs ship the Node-ABI native modules (better-sqlite3, sqlite-vec),
+  // and running Bun against them produces ABI mismatches. This also fixes
+  // pnpm-global installs, which copy the whole working tree — including .git
+  // and bun.lock — into the install dir and used to route through Bun even
+  // when the user installed via npm/pnpm.
+  const hasNpmLock = existsSync(resolve(pkgDir, "package-lock.json"));
+  const hasBunLock = existsSync(resolve(pkgDir, "bun.lock")) || existsSync(resolve(pkgDir, "bun.lockb"));
+  const tsxEntry = resolve(pkgDir, "node_modules/tsx/dist/cli.mjs");
+  const tsxAvailable = existsSync(tsxEntry);
+
+  if (hasNpmLock && tsxAvailable) {
     useSourceMode = true;
     sourceRunner = "node";
-    sourceArgs = [resolve(pkgDir, "node_modules/tsx/dist/cli.mjs"), tsEntry, ...process.argv.slice(2)];
+    sourceArgs = [tsxEntry, tsEntry, ...process.argv.slice(2)];
+  } else if (hasBunLock && hasBun()) {
+    useSourceMode = true;
+    sourceRunner = "bun";
+    sourceArgs = [tsEntry, ...process.argv.slice(2)];
+  } else if (tsxAvailable) {
+    useSourceMode = true;
+    sourceRunner = "node";
+    sourceArgs = [tsxEntry, tsEntry, ...process.argv.slice(2)];
   }
 }
 
diff --git a/test/bin-wrapper.test.ts b/test/bin-wrapper.test.ts
index f3c508f..4e7eef8 100644
--- a/test/bin-wrapper.test.ts
+++ b/test/bin-wrapper.test.ts
@@ -226,6 +226,21 @@ describe("bin/qmd package wrapper", () => {
     expect(result.args).toEqual([realpathSync(join(packageRoot, "src", "cli", "qmd.ts")), "--version"]);
   });
 
+  test("source checkout with both bun.lock and package-lock.json prefers node+tsx", () => {
+    // Mirrors the dist-mode "npm priority" rule: a working tree that has both
+    // lockfiles (because the user ran `npm install` against a repo that also
+    // ships bun.lock) installed native modules for Node's ABI, so source mode
+    // must route through tsx to avoid better-sqlite3 / sqlite-vec mismatches.
+    const { root, runtimeBin, capturePath } = makeTempFixture();
+    const packageRoot = makePackage(root, "qmd", ["bun.lock", "package-lock.json"], { source: true, tsx: true, git: true });
+
+    const result = runWrapper(join(packageRoot, "bin", "qmd"), runtimeBin, capturePath);
+
+    expect(result.runtime).toBe("node");
+    expect(result.scriptPath).toBe(realpathSync(join(packageRoot, "node_modules", "tsx", "dist", "cli.mjs")));
+    expect(result.args).toEqual([realpathSync(join(packageRoot, "src", "cli", "qmd.ts")), "--version"]);
+  });
+
   test("explains how to build when dist is missing and source cannot run", () => {
     const { root, runtimeBin } = makeTempFixture();
     const packageRoot = makePackage(root, "qmd", [], { dist: false });