diff --git a/deploy/mainnet/docker-compose.chatmock.yml b/deploy/mainnet/docker-compose.chatmock.yml
index bf80ef3..11678c2 100644
--- a/deploy/mainnet/docker-compose.chatmock.yml
+++ b/deploy/mainnet/docker-compose.chatmock.yml
@@ -45,7 +45,12 @@ services:
   chatmock:
     image: storagetime/chatmock:v1.36
     container_name: marketplace-mainnet-chatmock
-    command: ["serve"]
+    # --reasoning-effort low + --reasoning-summary none cap GPT-5 thinking
+    # tokens so a normal request returns well inside the supplier's
+    # OPENAI_TIMEOUT_MS budget. Default `medium`/`auto` produced 3-min
+    # timeouts in early mainnet testing (jobs bcc973bd / c85eaeec /
+    # 7e87afe6 on 2026-05-19).
+    command: ["serve", "--reasoning-effort", "low", "--reasoning-summary", "none"]
     restart: unless-stopped
     environment:
       CHATGPT_LOCAL_HOME: /data
diff --git a/deploy/mainnet/docker-compose.supplier-gpt.yml b/deploy/mainnet/docker-compose.supplier-gpt.yml
index 9ac888a..f3fb446 100644
--- a/deploy/mainnet/docker-compose.supplier-gpt.yml
+++ b/deploy/mainnet/docker-compose.supplier-gpt.yml
@@ -36,7 +36,7 @@ services:
     environment:
       LLM_BACKEND: openai
       OPENAI_BASE_URL: http://marketplace-mainnet-chatmock:8000
-      OPENAI_TIMEOUT_MS: "180000"
+      OPENAI_TIMEOUT_MS: "300000"
       PORT: "8080"
       # Enable LiveOgmiosProvider so submitTx/awaitTx actually broadcast.
       # Mirrors the testnet supplier compose; without this the supplier
diff --git a/supplier/src/jobRunner.ts b/supplier/src/jobRunner.ts
index c3b5faf..530ad77 100644
--- a/supplier/src/jobRunner.ts
+++ b/supplier/src/jobRunner.ts
@@ -112,6 +112,9 @@ export async function runChatJob(params: RunChatJobParams): Promise<void> {
         rawReason === "ollama_timeout" ? "ollama_failure"
           : rawReason === "openai_timeout" ? "openai_failure"
             : rawReason;
+      console.warn(
+        `[job_failed] jobId=${jobId} reason=${rawReason} httpStatus=502 msg=${message}`,
+      );
       deps.jobs.fail(jobId, {
         httpStatus: 502,
         reason: collapsedReason,
@@ -148,6 +151,9 @@ export async function runChatJob(params: RunChatJobParams): Promise<void> {
       });
     } catch (err) {
       const message = err instanceof Error ? err.message : String(err);
+      console.warn(
+        `[job_failed] jobId=${jobId} reason=submit_failed httpStatus=502 msg=${message}`,
+      );
       deps.jobs.fail(jobId, {
         httpStatus: 502,
         reason: "submit_failed",
@@ -161,6 +167,9 @@ export async function runChatJob(params: RunChatJobParams): Promise<void> {
       await deps.chain.awaitTx(buildResult.expectedTxHash, 60_000);
     } catch (err) {
       const msg = err instanceof Error ? err.message : String(err);
+      console.warn(
+        `[job_failed] jobId=${jobId} reason=submit_timeout httpStatus=502 msg=${msg}`,
+      );
       deps.jobs.fail(jobId, {
         httpStatus: 502,
         reason: "submit_timeout",
@@ -250,6 +259,9 @@ export async function runTtsJob(params: RunTtsJobParams): Promise<void> {
     } catch (err) {
       const reason = (err as piper.PiperError)?.reason ?? "piper_failure";
       const message = err instanceof Error ? err.message : String(err);
+      console.warn(
+        `[job_failed] jobId=${jobId} reason=${reason} httpStatus=502 msg=${message}`,
+      );
       deps.jobs.fail(jobId, {
         httpStatus: 502,
         reason: reason === "piper_timeout" ? "piper_failure" : reason,
@@ -288,6 +300,9 @@ export async function runTtsJob(params: RunTtsJobParams): Promise<void> {
       });
     } catch (err) {
       const message = err instanceof Error ? err.message : String(err);
+      console.warn(
+        `[job_failed] jobId=${jobId} reason=submit_failed httpStatus=502 msg=${message}`,
+      );
       deps.jobs.fail(jobId, {
         httpStatus: 502,
         reason: "submit_failed",
@@ -301,6 +316,9 @@ export async function runTtsJob(params: RunTtsJobParams): Promise<void> {
       await deps.chain.awaitTx(buildResult.expectedTxHash, 60_000);
     } catch (err) {
       const msg = err instanceof Error ? err.message : String(err);
+      console.warn(
+        `[job_failed] jobId=${jobId} reason=submit_timeout httpStatus=502 msg=${msg}`,
+      );
       deps.jobs.fail(jobId, {
         httpStatus: 502,
         reason: "submit_timeout",