Claude Opus 5.5 (effort default (no --effort flag) · thinking on) on Animate rain running down a window over blurred city lights in one self-contained HTML file

AClaude Opus 5.5default · thinking on · Claude Code 2.1.299 (headless -p) · cloud · 2026-10-22 · by @bobsiopener

Trust 80%Fully autonomoussuccess · first tryCompare

Estimated cost: $0.22
Wall time: 5m
Human step-ins: 0
Outcome: Pass

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Exact prompt

# Animate rain running down a window over blurred city lights in one self-contained HTML file Make a small animated scene: a rainy window. Write one file, `out/scene.html`, that works opened straight from disk with no network access. `spec.json` gives the page title, the stage size and the scene parameters. **Looks are not scored**: the page is opened in a headless browser (800x600 window, UTC time zone, network blocked) and checked by objective tests only. ## Scene contract - Draw the scene on one `<canvas>` or `<svg>` stage of `width` x `height` CSS pixels (spec.json), visible on load, with `<title>` containing spec.json `title`. - Animate continuously from load (`requestAnimationFrame` or timers); no click is needed unless stated below. - Expose `window.sceneState()`, returning the scene's current state in stage pixel coordinates (origin top-left of the stage): `{drops: [{x, y}, ...], lights: [{x, y}, ...]}`. Extra fields are fine. It must describe what is actually drawn. - Drops may restart at the top; keep each drop at the same array index. - The page must log no errors and throw no exceptions. Keep the file at most 200,000 bytes; no external scripts, fonts, images or URLs (inline everything). ## Checks (partial credit = share passed) 1. `self_contained`: `out/scene.html` exists, is at most 200,000 bytes, references no http(s) or protocol-relative URL, and requests nothing from the network when opened. 2. `has_canvas_or_svg`: a visible `<canvas>` or `<svg>` of at least 300x200 CSS pixels is on the page. 3. `frames_change`: over 3 s, some later screenshot differs from the first in at least 0.1% of pixels, and at least 3 of 30 screenshots differ. 4. `rain_runs_down`: `sceneState().drops` has at least `min_drops` entries and at least 60% of them move down (y increases by more than 1 px) between samples 1.5 s apart. 5. `city_lights`: `sceneState().lights` has exactly spec.json `lights` entries, all at distinct positions inside the stage. 6. `no_console_errors`: no uncaught exception, `console.error` or browser error is logged during the run. ## How this run works - Work on your own: nobody will answer questions in this task, and writing to `ask/` counts against the run. - Write only under `out/`. Create `out/` if it is missing. Inputs are synthetic; don't fetch anything from the network. - Scoring is partial credit: each listed check is pass/fail, and the score is the share passed. Numbers are compared to within 0.005 unless the task says otherwise.

Make a rainy window animation as one self-contained HTML file. A headless browser checks objective facts only: the file is offline and small, a canvas or SVG stage is drawn, frames change over time, the scene behaves as specified (rain runs down; city lights) and nothing errors. A poster PNG and a short MP4 are captured for the gallery. Looks are not scored. Original benchmark task written for usecaserank.com (not based on a specific public post). Headless, offline run on a reproducible fixture. Each run's notes say how its cost was measured (estimates are marked).

Success criteria: self_contained has_canvas_or_svg frames_change rain_runs_down city_lights no_console_errors

Setup notes: Batch 28 case d05-rain-on-window-city-lights (offline, synthetic inputs, seed 1721426854). Autonomous case: no stand-in user and no step-ins expected; any file the solver wrote to ask/ is counted as a measured intervention (0) and blocks a pass. Prompt = TASK.md verbatim. Hidden key kept outside the solver's work dir. Scored with the case's scorer (python3 score.py WORKDIR KEYDIR, absolute paths); pass = every check true and no ask/ files. Tools: Read/Write/Edit/Glob/Grep/Bash, web disabled. Single run, no retries. 1-min load average at scoring 1.40 (8 cores). Creative case: looks are not scored; objective checks run in headless google-chrome (800x600, UTC, network blocked, Date mocked). Gallery media (3 s capture: poster.png + clip.mp4) written by the scorer to a fresh MEDIA_DIR per run (media/<run>/), SHA-256 in evidence.media; a single failed scene check is rescored once (both recorded in rescore). Time-zone results depend on the system time-zone database: tzdata 2026c-0+deb13u1 (Python zoneinfo). Claude Code's own reported cost for claude-opus-5.5: $0.223319. Score: 6/6. Cost is an ESTIMATE: measured tokens x pricing.json list price (Claude Pro subscription, nothing billed); input_tokens include cache reads and writes. Single run.

Estimated cost List-price estimate; not actually billed.

Output

Metrics

Estimated cost: $0.22
Wall time: 5m
Human step-ins: 0
Turns: 8

Model usage
Model	Input tok	Output tok	Cost
AClaude Opus 5.5anthropic/claude-opus-5.5effort default (no --effort flag) · thinking on	175,562	5,269	$0.22

Reproduce this run

Use the use case prompt on the use case page.
Same setup: Claude Opus 5.5 (anthropic/claude-opus-5.5, effort default (no --effort flag) · thinking on) via Claude Code 2.1.299 (headless -p), cloud.
It counts as a success only if it meets every success criterion: self_contained has_canvas_or_svg frames_change rain_runs_down city_lights no_console_errors
Log model, tokens, wall time, human step-ins and the evidence log, then submit it as a reproduction. A different model? Submit a head-to-head rerun.

How runs are scored: Methodology.

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Automated checks

Trust 80% comes from these checks (how Trust % works).

Run date is not in the future : passed
Model is in the dated pricing table : passed
Cost recomputed from tokens matches : passed
Cached tokens are consistent : passed
Output throughput is plausible : passed
Autonomy matches step-ins : passed
Step-ins do not exceed turns : passed
Retries agree with first-try result : passed
Evidence log SHA-256 matches : passed
Evidence log is substantial : passed

Evidence log

[
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  "stop_reason": "end_turn",
  "session_id": "[REDACTED]",
  "total_cost_usd": 0.22331900000000002,
  "usage": {
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   "cache_creation_input_tokens": 10611,
   "cache_read_input_tokens": 164935,
   "output_tokens": 5269,
   "output_tokens_details": {
    "thinking_tokens": 798
   },
   "server_tool_use": {
    "web_search_requests": 0,
    "web_fetch_requests": 0
   },
   "service_tier": "standard",
   "cache_creation": {
    "ephemeral_1h_input_tokens": 10611,
    "ephemeral_5m_input_tokens": 0
   },
   "inference_geo": "global",
   "iterations": [
    {
     "input_tokens": 2,
     "output_tokens": 513,
     "cache_read_input_tokens": 24218,
     "cache_creation_input_tokens": 957,
     "cache_creation": {
      "ephemeral_5m_input_tokens": 0,
      "ephemeral_1h_input_tokens": 957
     },
     "type": "message"
    }
   ],
   "speed": "standard",
   "fallback_credit": null
  },
  "modelUsage": {
   "claude-opus-5-5": {
    "inputTokens": 16,
    "outputTokens": 5269,
    "cacheReadInputTokens": 164935,
    "cacheCreationInputTokens": 10611,
    "webSearchRequests": 0,
    "costUSD": 0.22331900000000002,
    "contextWindow": 1000000,
    "maxOutputTokens": 128000,
    "thinkingTokens": 798,
    "canonicalModel": "claude-opus-5-5",
    "provider": "firstParty",
    "costBasis": "list"
   }
  },
  "permission_denials": [],
  "terminal_reason": "completed",
  "fast_mode_state": "off",
  "fast_mode_disabled_reason": "sdk_opt_in_required",
  "subagent_stats": {
   "spawned": 0,
   "requested": {
    "background": 0,
    "foreground": 0,
    "unset": 0
   },
   "started_in_background": 0,
   "max_depth": 0,
   "spawned_by_subagents": 0,
   "completed": 0,
   "failed": 0,
   "killed": {
    "parent": 0,
    "user": 0,
    "system": 0
   },
   "refused": {
    "depth_limit": 0,
    "concurrency_limit": 0,
    "budget": 0
   },
   "by_type": {}
  },
  "safety_stops": 0,
  "is_error": false,
  "num_turns": 8,
  "subtype": "success",
  "api_error_status": null,
  "result": "I've written `out/scene.html`. I tested it in headless Chrome (800x600 window), but not with the real grader.\n\n- **Drops:** there are 40 (the spec asks for at least 24). In a check 1.5 s apart, 35 of the 40 moved down, which is 87.5% against the 60% needed. The few that fail are drops that restarted at the top during the gap. Each drop keeps its array index when it restarts.\n- **Lights:** there are exactly 11 blurred city lights at distinct positions, all inside the stage. They flicker gently, but they don't move.\n- **Page:** it's a 720x480 canvas titled \"Rainy Window 718\". The file is about 4 KB and contains no URLs. I added an empty inline favicon so the browser doesn't request one.\n- **Errors:** the headless run showed no page errors. The only log messages were Chrome's own system (dbus) warnings, which come from the test machine rather than the page.\n\nOne fix came out of testing. In the first headless run the drops didn't move at all, because animation callbacks (`requestAnimationFrame`) weren't firing. The scene now moves by elapsed real time instead. It updates on each animation frame, on a 50 ms timer as a backup, and whenever `sceneState()` is called, so the reported positions always match what's drawn.\n\nNot checked: I didn't take screenshots to confirm the 3-second frame-change check, and I didn't watch network traffic directly.",
  "ttft_ms": 1847,
  "type": "result",
  "duration_ms": 256073,
  "uuid": "[REDACTED]",
  "ttft_stream_ms": 819,
  "time_to_request_ms": 268,
  "first_content_frame_ms": 820,
  "queued_turn_count": 0,
  "result_index": 0
 }
]