After runtime transcript — sanitized allowlisted extraction
Revision: ebc9dbbd003f0c0bc2f4b09f506512b31d9dc95d
Environment: Linux x64; existing vp run dev with isolated worktree .t3; real T3 MCP -> broker -> server-browser Chromium (environment supplied by lead).
Target: localhost HTTP response delayed 20 seconds; fresh-tab preview_open, reuseExistingTab:false.
No new runtime or browser started for evidence extraction.
Provider source: .t3/userdata/logs/provider/events.*.log
Server source: .t3/userdata/logs/server.trace.ndjson
Only operation arguments, timestamps, durations, diagnostic and cause retained; no credentials, customer history or customer paths.

Stable AFTER tool record:
{
  "sourceLine": 148,
  "timestamp": "2026-10-24T10:05:34.202Z",
  "tool": "preview_open",
  "arguments": {
    "url": "http://127.0.0.1:1337/",
    "reuseExistingTab": false
  },
  "durationMs": 15696,
  "message": "Preview automation open timed out after 15000ms."
}
Agent-reported elapsed wall time: 15.702 seconds (provider source line 153).
MCP result structuredContent: null; timeoutMs is not separately exposed in this tool response.
Server corroboration:
{
  "sourceLine": 16973,
  "name": "PreviewAutomationBroker.invoke",
  "durationMs": 15660.010637,
  "diagnostic": "PreviewAutomationTimeoutError: Preview automation open timed out after 15000ms.",
  "cause": "page.goto: Timeout 15000ms exceeded."
}

Attempt log (chronological):

BEFORE baseline, accepted
{
  "sourceLine": 33,
  "timestamp": "2026-10-24T09:59:16.356Z",
  "tool": "preview_open",
  "arguments": {
    "url": "http://127.0.0.1:1337/",
    "reuseExistingTab": false
  },
  "durationMs": 21769,
  "message": "Preview automation open timed out after 660000ms."
}

AFTER discarded infrastructure interruption during dev reload; not bug evidence
{
  "sourceLine": 72,
  "timestamp": "2026-10-24T10:03:27.218Z",
  "tool": "preview_open",
  "arguments": {
    "url": "http://127.0.0.1:1337/",
    "reuseExistingTab": false
  },
  "durationMs": 14854,
  "message": "tool call error: tool call failed for `t3-code/preview_open`\n\nCaused by:\n    Transport send error: Transport [codex_rmcp_client::event_notification_transport::EventNotificationTransport<rmcp::transport::worker::WorkerTransport<rmcp::transport::streamable_http_client::StreamableHttpClientWorker<codex_rmcp_client::http_client_adapter::StreamableHttpClientAdapter>>>] error: unexpected server response: HTTP 503: "
}

AFTER discarded infrastructure interruption during dev reload; not bug evidence
{
  "sourceLine": 110,
  "timestamp": "2026-10-24T10:04:17.041Z",
  "tool": "preview_open",
  "arguments": {
    "url": "http://127.0.0.1:1337/",
    "reuseExistingTab": false
  },
  "durationMs": 5136,
  "message": "tool call error: tool call failed for `t3-code/preview_open`\n\nCaused by:\n    Transport send error: Transport [codex_rmcp_client::event_notification_transport::EventNotificationTransport<rmcp::transport::worker::WorkerTransport<rmcp::transport::streamable_http_client::StreamableHttpClientWorker<codex_rmcp_client::http_client_adapter::StreamableHttpClientAdapter>>>] error: unexpected server response: HTTP 503: "
}

AFTER stable, accepted
{
  "sourceLine": 148,
  "timestamp": "2026-10-24T10:05:34.202Z",
  "tool": "preview_open",
  "arguments": {
    "url": "http://127.0.0.1:1337/",
    "reuseExistingTab": false
  },
  "durationMs": 15696,
  "message": "Preview automation open timed out after 15000ms."
}