abi/screenshot-to-code · error · Error

data.detail || "Request failed"

Error message

data.detail || "Request failed"

What it means

Client-side fallback error thrown by the eval sessions UI when POST ${HTTP_BACKEND_URL}/eval-sessions returns a non-2xx status. It surfaces whatever the FastAPI backend put in the response body's `detail` field, or the generic string 'Request failed' when the body has no detail (e.g. empty body or non-JSON error page). The error is then shown via toast.error(String(error)), so the user sees 'Error: <detail>'.

Source

Thrown at frontend/src/components/evals/EvalSessionsPage.tsx:325

      toast.error("Failed to activate session.");
    }
  };

  const handleCreate = async () => {
    if (!newSessionSet) return;
    setIsCreating(true);
    try {
      const response = await fetch(`${HTTP_BACKEND_URL}/eval-sessions`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          eval_set: newSessionSet,
          name: newSessionName.trim() || null,
        }),
      });
      if (!response.ok) {
        const data = await response.json();
        throw new Error(data.detail || "Request failed");
      }
      const created: EvalSession = await response.json();
      setNewSessionName("");
      toast.success(`Session "${created.name}" started.`);
      await fetchSessions();
      loadMatrix(created.session_id);
    } catch (error) {
      console.error("Error creating session", error);
      toast.error(String(error));
    } finally {
      setIsCreating(false);
    }
  };

  const openRun = (runId: string) => {
    navigate(`/evals/agent-runs?run=${encodeURIComponent(runId)}`);
  };

View on GitHub (pinned to d026163f58)

Solutions

1. Open browser devtools Network tab and inspect the actual response status and body to see the backend's detail message.
2. Verify the backend is running and HTTP_BACKEND_URL points at it (default port 7001).
3. If the detail mentions the set name, fix or create the eval set before starting a session.
4. Make response parsing defensive: check content-type before .json() so an HTML error page does not mask the real status code.

Example fix

// before
if (!response.ok) {
  const data = await response.json();
  throw new Error(data.detail || "Request failed");
}

// after
if (!response.ok) {
  let detail = `Request failed (${response.status})`;
  try {
    const data = await response.json();
    if (data?.detail) detail = String(data.detail);
  } catch { /* non-JSON body */ }
  throw new Error(detail);
}

const ok = typeof newSessionSet === "string" && /^[A-Za-z0-9][A-Za-z0-9._ -]*$/.test(newSessionSet);
if (!ok) { toast.error("Invalid set name"); return; }

try {
  const res = await fetch(url, opts);
  if (!res.ok) {
    const body = await res.json().catch(() => null);
    throw new Error(body?.detail ?? `Request failed (${res.status})`);
  }
  return await res.json();
} catch (e) {
  toast.error(e instanceof Error ? e.message : String(e));
} finally {
  setIsCreating(false);
}

When it happens

Trigger: Clicking 'start session' in EvalSessionsPage with a set name that fails server-side validation (invalid characters, unknown set), backend returning 422/500, or the backend being unreachable/proxy returning an HTML error page so response.json() itself rejects and jumps to the generic catch.

Common situations: Backend not running on the configured HTTP port, CORS/proxy intercepting the request, creating a session for an eval set that was deleted on disk, or FastAPI raising HTTPException with a detail message the UI just echoes.

Related errors

• An unexpected error occurred: {exc}
• Anthropic API key not found
• Gemini API key not found
• OpenAI API key not found
• No stack was provided

AI-assisted analysis of abi/screenshot-to-code@d026163f58 (2026-08-14). Data as JSON: /api/errors/45fdd3c7ae6ba689. Report an issue: GitHub.