diff --git a/src/gateway/openai-http.ts b/src/gateway/openai-http.ts
index e85e0aac961..2b9df17cdfe 100644
--- a/src/gateway/openai-http.ts
+++ b/src/gateway/openai-http.ts
@@ -5,6 +5,7 @@ import { buildHistoryContextFromEntries, type HistoryEntry } from "../auto-reply
 import { createDefaultDeps } from "../cli/deps.js";
 import { agentCommand } from "../commands/agent.js";
 import { emitAgentEvent, onAgentEvent } from "../infra/agent-events.js";
+import { logWarn } from "../logger.js";
 import { defaultRuntime } from "../runtime.js";
 import { authorizeGatewayConnect, type ResolvedGatewayAuth } from "./auth.js";
 import {
@@ -264,8 +265,9 @@ export async function handleOpenAiHttpRequest(
         usage: { prompt_tokens: 0, completion_tokens: 0, total_tokens: 0 },
       });
     } catch (err) {
+      logWarn(`openai-compat: chat completion failed: ${String(err)}`);
       sendJson(res, 500, {
-        error: { message: String(err), type: "api_error" },
+        error: { message: "internal error", type: "api_error" },
       });
     }
     return true;
@@ -394,6 +396,7 @@ export async function handleOpenAiHttpRequest(
         });
       }
     } catch (err) {
+      logWarn(`openai-compat: streaming chat completion failed: ${String(err)}`);
       if (closed) {
         return;
       }
@@ -405,7 +408,7 @@ export async function handleOpenAiHttpRequest(
         choices: [
           {
             index: 0,
-            delta: { content: `Error: ${String(err)}` },
+            delta: { content: "Error: internal error" },
             finish_reason: "stop",
           },
         ],
diff --git a/src/gateway/openresponses-http.ts b/src/gateway/openresponses-http.ts
index dae20ac51d6..c4d8b9bef19 100644
--- a/src/gateway/openresponses-http.ts
+++ b/src/gateway/openresponses-http.ts
@@ -16,6 +16,7 @@ import { buildHistoryContextFromEntries, type HistoryEntry } from "../auto-reply
 import { createDefaultDeps } from "../cli/deps.js";
 import { agentCommand } from "../commands/agent.js";
 import { emitAgentEvent, onAgentEvent } from "../infra/agent-events.js";
+import { logWarn } from "../logger.js";
 import {
   DEFAULT_INPUT_FILE_MAX_BYTES,
   DEFAULT_INPUT_FILE_MAX_CHARS,
@@ -485,8 +486,9 @@ export async function handleOpenResponsesHttpRequest(
       }
     }
   } catch (err) {
+    logWarn(`openresponses: request parsing failed: ${String(err)}`);
     sendJson(res, 400, {
-      error: { message: String(err), type: "invalid_request_error" },
+      error: { message: "invalid request", type: "invalid_request_error" },
     });
     return true;
   }
@@ -502,8 +504,9 @@ export async function handleOpenResponsesHttpRequest(
     resolvedClientTools = toolChoiceResult.tools;
     toolChoicePrompt = toolChoiceResult.extraSystemPrompt;
   } catch (err) {
+    logWarn(`openresponses: tool configuration failed: ${String(err)}`);
     sendJson(res, 400, {
-      error: { message: String(err), type: "invalid_request_error" },
+      error: { message: "invalid tool configuration", type: "invalid_request_error" },
     });
     return true;
   }
@@ -617,12 +620,13 @@ export async function handleOpenResponsesHttpRequest(
 
       sendJson(res, 200, response);
     } catch (err) {
+      logWarn(`openresponses: non-stream response failed: ${String(err)}`);
       const response = createResponseResource({
         id: responseId,
         model,
         status: "failed",
         output: [],
-        error: { code: "api_error", message: String(err) },
+        error: { code: "api_error", message: "internal error" },
       });
       sendJson(res, 500, response);
     }
@@ -912,6 +916,7 @@ export async function handleOpenResponsesHttpRequest(
         });
       }
     } catch (err) {
+      logWarn(`openresponses: streaming response failed: ${String(err)}`);
       if (closed) {
         return;
       }
@@ -922,7 +927,7 @@ export async function handleOpenResponsesHttpRequest(
         model,
         status: "failed",
         output: [],
-        error: { code: "api_error", message: String(err) },
+        error: { code: "api_error", message: "internal error" },
         usage: finalUsage,
       });
 
diff --git a/src/gateway/tools-invoke-http.ts b/src/gateway/tools-invoke-http.ts
index 813d122f787..24e91754cd2 100644
--- a/src/gateway/tools-invoke-http.ts
+++ b/src/gateway/tools-invoke-http.ts
@@ -348,9 +348,10 @@ export async function handleToolsInvokeHttpRequest(
     const result = await (tool as any).execute?.(`http-${Date.now()}`, toolArgs);
     sendJson(res, 200, { ok: true, result });
   } catch (err) {
+    logWarn(`tools-invoke: tool execution failed: ${String(err)}`);
     sendJson(res, 400, {
       ok: false,
-      error: { type: "tool_error", message: err instanceof Error ? err.message : String(err) },
+      error: { type: "tool_error", message: "tool execution failed" },
     });
   }