diff --git a/src/server/execute.ts b/src/server/execute.ts
index 7b9ba36..cbdfb41 100644
--- a/src/server/execute.ts
+++ b/src/server/execute.ts
@@ -544,8 +544,11 @@ async function streamAndAwaitJob(
         await new Promise<void>((resolve) => setTimeout(resolve, KEEPALIVE_INTERVAL_MS));
         if (logStopSignal.stopped || cancelSignal.cancelled) break;
         try {
+          // Prefer PAPERCLIP_DEV_API_KEY if set (allows dev instance key to be
+          // distinct from the main-instance run JWT in PAPERCLIP_API_KEY).
+          const apiKey = process.env.PAPERCLIP_DEV_API_KEY ?? process.env.PAPERCLIP_API_KEY ?? "";
           const resp = await fetch(`${apiUrl}/api/issues/${issueId}`, {
-            headers: { Authorization: `Bearer ${process.env.PAPERCLIP_API_KEY ?? ""}` },
+            headers: { Authorization: `Bearer ${apiKey}` },
           });
           if (resp.ok) {
             const data = await resp.json() as { status?: string };
diff --git a/src/server/job-manifest.ts b/src/server/job-manifest.ts
index c74fb6c..2e31dac 100644
--- a/src/server/job-manifest.ts
+++ b/src/server/job-manifest.ts
@@ -173,6 +173,12 @@ function buildEnvVars(
   if (selfPod.inheritedEnv.PAPERCLIP_API_URL) {
     paperclipEnv.PAPERCLIP_API_URL = selfPod.inheritedEnv.PAPERCLIP_API_URL;
   }
+  // Inherit PAPERCLIP_DEV_API_KEY if set (dev-instance key, distinct from the
+  // main-instance run JWT in PAPERCLIP_API_KEY). Used by the external cancel
+  // polling in execute.ts to authenticate against the dev Paperclip instance.
+  if (selfPod.inheritedEnv.PAPERCLIP_DEV_API_KEY) {
+    paperclipEnv.PAPERCLIP_DEV_API_KEY = selfPod.inheritedEnv.PAPERCLIP_DEV_API_KEY;
+  }
 
   // Layer 3: Inherited from Deployment (Bedrock, API keys, etc.)
   const merged: Record<string, string> = {