affaan-m/ECC · warning · Error

HTTP ${res.status}

Error message

HTTP ${res.status}

What it means

Thrown inside the plan-canvas browser UI's send() function when the POST to /api/session/{key}/feedback returns a non-2xx HTTP status. The fetch promise resolves but res.ok is false, so the client throws to surface the status code. The catch handler then shows a 'Send failed' message to the reviewer.

Source

Thrown at scripts/lib/plan-canvas/ui.js:385

    if (ended || sending) return;
    const items = queue.slice();
    if (extraItems) items.push(...extraItems);
    const text = input.value.trim();
    if (text) items.push({ kind: 'chat', text });
    if (!items.length) {
      statusEl.textContent = 'Nothing to send yet - annotate the plan or type a message.';
      return;
    }
    sending = true;
    sendBtn.disabled = true;
    statusEl.textContent = 'Sending\\u2026';
    try {
      const res = await fetch('/api/session/' + key + '/feedback', {
        method: 'POST',
        headers: { 'content-type': 'application/json' },
        body: JSON.stringify({ items })
      });
      if (!res.ok) throw new Error('HTTP ' + res.status);
      const body = await res.json().catch(() => ({}));
      queue = [];
      persistQueue();
      renderQueue();
      input.value = '';
      // Say what actually happened: a parked agent takes the batch on the
      // spot, otherwise it sits in the queue until the agent checks in.
      statusEl.textContent = body.presence === 'thinking' || body.presence === 'typing'
        ? 'Delivered. Your agent has it.'
        : 'Queued. Your agent picks this up the moment it checks in.';
      if (body.presence) applyPresence(body.presence);
    } catch (err) {
      statusEl.textContent = 'Send failed (' + err.message + ') - is the canvas server still running?';
    } finally {
      sending = false;
      sendBtn.disabled = ended;
    }
  }

View on GitHub (pinned to 01e15490f0)

Solutions

1. Check the plan-canvas server is still running and the session key is still valid.
2. Reload the canvas page to obtain a fresh session key from the server boot payload.
3. Inspect the server logs for the non-2xx cause; retry the send once the server is healthy.
4. If the session ended, start a new review session rather than retrying the dead one.

Example fix

// before (client side)
if (!res.ok) throw new Error('HTTP ' + res.status); // bare status, no body

// after (client side) — include server detail for diagnostics
if (!res.ok) {
  const detail = await res.text().catch(() => '');
  throw new Error(`HTTP ${res.status}: ${detail || res.statusText}`);
}

// Browser-side preflight: confirm session is live before sending.
const probe = await fetch('/api/session/' + key).catch(() => null);
if (!probe || !probe.ok) {
  statusEl.textContent = 'Session unavailable. Reload to get a new key.';
  return;
}
// then proceed with the POST

try {
  const res = await fetch('/api/session/' + key + '/feedback', {...});
  if (!res.ok) throw new Error('HTTP ' + res.status);
  // ...
} catch (err) {
  statusEl.textContent = 'Send failed (' + err.message + ') - is the canvas server still running?';
  // offer a reload; do not infinite-retry a dead session
}

When it happens

Trigger: The plan-canvas server returns 400 (malformed items), 404 (unknown session key), 409 (session ended), or 500 (server error); the server process restarted and lost in-memory session state; a proxy/gateway between browser and server returns a 502/503.

Common situations: The agent ended the session server-side but the browser tab was still open; the canvas server was killed and relaunched; a long-idle review tab whose session expired; the feedback payload shape changed across versions and the server rejects it.

Related errors

• open failed (HTTP ${res.statusCode})
• invalid plan-canvas server port: ${port}
• plan-canvas request path must be root-relative
• plan-canvas request path must stay on the loopback server
• unsupported plan-canvas request path: ${url.pathname}

AI-assisted analysis of affaan-m/ECC@01e15490f0 (2026-08-13). Data as JSON: /api/errors/67acbbfaf319868d. Report an issue: GitHub.