diff --git a/.agents/pm/history/pm-linear-lonp.jsonl b/.agents/pm/history/pm-linear-lonp.jsonl
new file mode 100644
index 00000000..82efd8c8
--- /dev/null
+++ b/.agents/pm/history/pm-linear-lonp.jsonl
@@ -0,0 +1,5 @@
+{"ts":"2026-08-10T06:06:04.494Z","author":"claude","author_source":"asserted","agent_harness":"claude-code","agent_instance":"507208966ab0dc1f88c5707f","agent_provenance":{"model":null,"effort":{"value":"xhigh","source":"environment"},"role":{"value":"1","source":"environment"},"topic":null},"op":"create","patch":[{"op":"add","path":"/metadata/id","value":"pm-linear-lonp"},{"op":"add","path":"/metadata/title","value":"The shared script launcher skipped every gate it guarded when a path could not be resolved"},{"op":"add","path":"/metadata/description","value":"isMainInvocation caught a realpathSync failure and returned false, which makes runIfMain treat a direct invocation as a library import and skip main, so a required release check exits zero having done nothing."},{"op":"add","path":"/metadata/type","value":"Issue"},{"op":"add","path":"/metadata/status","value":"open"},{"op":"add","path":"/metadata/priority","value":1},{"op":"add","path":"/metadata/tags","value":["docstrings","gate","release"]},{"op":"add","path":"/metadata/created_at","value":"2026-08-10T06:06:04.494Z"},{"op":"add","path":"/metadata/updated_at","value":"2026-08-10T06:06:04.494Z"},{"op":"add","path":"/metadata/author","value":"claude"}],"before_hash":"3cc22dff72be7b14824654a7a64ea62b04799939b2fee54c1b5f52ca60bf6df0","after_hash":"d83717695cfc3e5beee8945caa3001eba99fd9b60321e3405be40bed8bf0ee79","message":""}
+{"ts":"2026-08-10T06:06:30.695Z","author":"claude","author_source":"asserted","agent_harness":"claude-code","agent_instance":"507208966ab0dc1f88c5707f","agent_provenance":{"model":null,"effort":{"value":"xhigh","source":"environment"},"role":{"value":"1","source":"environment"},"topic":null},"op":"note_add","patch":[{"op":"replace","path":"/metadata/updated_at","value":"2026-08-10T06:06:30.695Z"},{"op":"add","path":"/metadata/notes","value":[{"created_at":"2026-08-10T06:06:30.695Z","author":"claude","text":"The refactor into script-launcher.ts is why the fleet-wide sweep missed this repo. A survey that grepped scripts/docstring-gate.ts for realpathSync found nothing here, because the guard had moved into the shared launcher and the gate merely re-exports it. Factoring a defect out of the file people search makes it invisible to the search."}]}],"before_hash":"d83717695cfc3e5beee8945caa3001eba99fd9b60321e3405be40bed8bf0ee79","after_hash":"69e2367d836822c37b6d425dca48518d104dc428db5b088e2fe9be69291699d6"}
+{"ts":"2026-08-10T06:06:31.150Z","author":"claude","author_source":"asserted","agent_harness":"claude-code","agent_instance":"507208966ab0dc1f88c5707f","agent_provenance":{"model":null,"effort":{"value":"xhigh","source":"environment"},"role":{"value":"1","source":"environment"},"topic":null},"op":"note_add","patch":[{"op":"add","path":"/metadata/notes/1","value":{"created_at":"2026-08-10T06:06:31.150Z","author":"claude","text":"Unlike the copies in other repositories this variant resolves both sides through realpathSync, deliberately, to normalise Windows drive-letter casing. That reasoning is sound and was kept. Only the catch was removed, so the fix does not reintroduce the casing bug the both-sides comparison exists to prevent."}},{"op":"replace","path":"/metadata/updated_at","value":"2026-08-10T06:06:31.150Z"}],"before_hash":"69e2367d836822c37b6d425dca48518d104dc428db5b088e2fe9be69291699d6","after_hash":"a62c0754a976597f2880898e12b929880832dc3e8247a7cf2cb1421f85a48181"}
+{"ts":"2026-08-10T06:07:08.993Z","author":"claude","author_source":"asserted","agent_harness":"claude-code","agent_instance":"507208966ab0dc1f88c5707f","agent_provenance":{"model":null,"effort":{"value":"xhigh","source":"environment"},"role":{"value":"1","source":"environment"},"topic":null},"op":"note_add","patch":[{"op":"add","path":"/metadata/notes/2","value":{"created_at":"2026-08-10T06:07:08.993Z","author":"claude","text":"The refactor into script-launcher.ts is why the fleet-wide sweep missed this repo. A survey that grepped scripts/docstring-gate.ts for realpathSync found nothing here, because the guard had moved into the shared launcher and the gate merely re-exports it."}},{"op":"replace","path":"/metadata/updated_at","value":"2026-08-10T06:07:08.993Z"}],"before_hash":"a62c0754a976597f2880898e12b929880832dc3e8247a7cf2cb1421f85a48181","after_hash":"f1f7cbf733fa48cd8a34ebf3a2635acf19818a5ea19b53a7de198b12cdecdd1e"}
+{"ts":"2026-08-10T06:07:28.390Z","author":"claude","author_source":"asserted","agent_harness":"claude-code","agent_instance":"507208966ab0dc1f88c5707f","agent_provenance":{"model":null,"effort":{"value":"xhigh","source":"environment"},"role":{"value":"1","source":"environment"},"topic":null},"op":"note_delete","patch":[{"op":"remove","path":"/metadata/notes/2"},{"op":"replace","path":"/metadata/updated_at","value":"2026-08-10T06:07:28.390Z"}],"before_hash":"f1f7cbf733fa48cd8a34ebf3a2635acf19818a5ea19b53a7de198b12cdecdd1e","after_hash":"0aa88d05f28c9081abb025c0d8a9a2b5cdc69e92fb7ac4388b325cc71c3fd18e"}
diff --git a/.agents/pm/issues/pm-linear-lonp.toon b/.agents/pm/issues/pm-linear-lonp.toon
new file mode 100644
index 00000000..5574a571
--- /dev/null
+++ b/.agents/pm/issues/pm-linear-lonp.toon
@@ -0,0 +1,14 @@
+id: pm-linear-lonp
+title: The shared script launcher skipped every gate it guarded when a path could not be resolved
+description: "isMainInvocation caught a realpathSync failure and returned false, which makes runIfMain treat a direct invocation as a library import and skip main, so a required release check exits zero having done nothing."
+type: Issue
+status: open
+priority: 1
+tags[3]: docstrings,gate,release
+created_at: "2026-08-10T06:06:04.494Z"
+updated_at: "2026-08-10T06:07:28.390Z"
+author: claude
+notes[2]{created_at,author,text}:
+  "2026-08-10T06:06:30.695Z",claude,"The refactor into script-launcher.ts is why the fleet-wide sweep missed this repo. A survey that grepped scripts/docstring-gate.ts for realpathSync found nothing here, because the guard had moved into the shared launcher and the gate merely re-exports it. Factoring a defect out of the file people search makes it invisible to the search."
+  "2026-08-10T06:06:31.150Z",claude,"Unlike the copies in other repositories this variant resolves both sides through realpathSync, deliberately, to normalise Windows drive-letter casing. That reasoning is sound and was kept. Only the catch was removed, so the fix does not reintroduce the casing bug the both-sides comparison exists to prevent."
+body: ""
diff --git a/scripts/script-launcher.ts b/scripts/script-launcher.ts
index 1932a144..aa580c5c 100644
--- a/scripts/script-launcher.ts
+++ b/scripts/script-launcher.ts
@@ -22,22 +22,30 @@ import { fileURLToPath } from "node:url";
  * return a different drive-letter casing than the URL form, so an exact href
  * comparison would treat a direct invocation as a library import and silently
  * skip `main`. Resolving both sides through `realpathSync` after converting the
- * URL back to a path removes that casing and symlink ambiguity. A release
- * script that no-ops without erroring is worse than one that throws, so fail
- * closed if either path cannot be resolved.
+ * URL back to a path removes that casing and symlink ambiguity.
+ *
+ * An unresolvable path **propagates** rather than returning false. The two
+ * outcomes are not equally safe: returning false makes the caller treat the
+ * script as a library import and skip `main`, so a required release check
+ * exits 0 having done nothing — the one failure these gates exist to prevent.
+ * Letting `realpathSync` throw turns that into a loud non-zero exit. Either
+ * path failing to resolve after Node has already loaded the module means the
+ * environment is broken, and a broken environment must not silently satisfy a
+ * gate.
+ *
+ * A genuinely different entry path still returns false, which is how a test
+ * importing a script declines to run it.
  *
  * @param argv - The process argv slice to inspect.
  * @param moduleUrl - The `import.meta.url` of the module that might be main.
- * @returns True when `argv[1]` resolves to this module's own real path.
+ * @returns True when `argv[1]` resolves to this module's own real path, false
+ *          when it resolves to a different one.
+ * @throws Whatever `realpathSync` throws when either path cannot be resolved.
  */
 export function isMainInvocation(argv: readonly string[], moduleUrl: string): boolean {
   const entry = argv[1];
   if (entry === undefined) return false;
-  try {
-    return realpathSync(entry) === realpathSync(fileURLToPath(moduleUrl));
-  } catch {
-    return false;
-  }
+  return realpathSync(entry) === realpathSync(fileURLToPath(moduleUrl));
 }
 
 /**
diff --git a/test/docstring-gate.test.ts b/test/docstring-gate.test.ts
index af91752d..da81ada5 100644
--- a/test/docstring-gate.test.ts
+++ b/test/docstring-gate.test.ts
@@ -138,3 +138,22 @@ test("docstring gate main writes a success line to stdout and exits 0", () => {
   assert.equal(observedExitCode, 0);
   assert.match(stdout, /docstring-gate:.*documented\.\n$/);
 });
+
+test("docstring gate isMainInvocation throws rather than skipping the gate when a path cannot be resolved", () => {
+  const root = mkdtempSync(join(tmpdir(), "pm-linear-docstring-unresolvable-"));
+  try {
+    const script = join(root, "docstring-gate.ts");
+    writeFileSync(script, "");
+    const url = pathToFileURL(script).href;
+    // Returning false here would make the caller treat the script as a library
+    // import and skip main, so a required release check exits 0 having done
+    // nothing. Crashing is the safe outcome, so assert it is what happens.
+    assert.throws(
+      () => isMainInvocation([process.execPath, join(root, "does-not-exist.ts")], url),
+      /ENOENT/,
+      "an unresolvable entry must propagate, not silently decline to run the gate",
+    );
+  } finally {
+    rmSync(root, { recursive: true, force: true });
+  }
+});