diff --git a/src/runner/LightRunClient.ts b/src/runner/LightRunClient.ts
index 0ffc892..95870cf 100644
--- a/src/runner/LightRunClient.ts
+++ b/src/runner/LightRunClient.ts
@@ -25,6 +25,16 @@ export interface RunState {
 
 const POLL_INTERVAL_MS = 500;
 
+/*
+ * Safety net for a wedged run. A bounded node (timeout > 0) is killed by
+ * light-runner at its timeout and turns terminal shortly after; if polling
+ * still sees `running` past timeout + this grace (image pull, extraction and
+ * teardown all happen outside the container's own timeout window), the run is
+ * stuck - fail loudly instead of looping forever. Nodes with timeout 0 opt out
+ * of any limit and keep polling indefinitely.
+ */
+const POLL_GRACE_MS = 300_000;
+
 let seq = 0;
 
 function sleep(ms: number): Promise<void> {
@@ -122,7 +132,7 @@ export class LightRunClient {
 
       const accepted = (await res.json()) as { id: string };
       onRunId(accepted.id);
-      const state = await this.pollUntilDone(accepted.id, onLog);
+      const state = await this.pollUntilDone(accepted.id, onLog, node.timeout);
 
       let output: Record<string, unknown> = {};
       const artifactName = OUTPUT_FILE;
@@ -174,8 +184,9 @@ export class LightRunClient {
     }
   }
 
-  private async pollUntilDone(runId: string, onLog?: (line: string) => void): Promise<RunState> {
+  private async pollUntilDone(runId: string, onLog?: (line: string) => void, timeoutMs = 0): Promise<RunState> {
     let printed = 0;
+    const deadline = timeoutMs > 0 ? Date.now() + timeoutMs + POLL_GRACE_MS : 0;
     while (true) {
       const res = await fetch(`${this.url}/runs/${runId}`, { headers: this.headers() });
       if (!res.ok) {
@@ -189,6 +200,13 @@ export class LightRunClient {
         printed = state.logs.length;
       }
       if (state.status !== 'running') return state;
+      if (deadline > 0 && Date.now() > deadline) {
+        throw new Error(
+          `light-run run ${runId} still running after ${Math.round(
+            (timeoutMs + POLL_GRACE_MS) / 1000,
+          )}s; treating it as wedged`,
+        );
+      }
       await sleep(POLL_INTERVAL_MS);
     }
   }