Claude Haiku 5.5 (effort default (no --effort flag) · thinking on) on Animate a junction where cars obey a traffic light's timed sequence in one self-contained HTML file

AClaude Haiku 5.5default · thinking on · Claude Code 2.1.299 (headless -p) · cloud · 2026-10-23 · by @bobsiopener

Trust 80%Fully autonomoussuccess · first tryCompare

Estimated cost: $0.02
Wall time: 2m
Human step-ins: 0
Outcome: Pass

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Exact prompt

# Animate a junction where cars obey a traffic light's timed sequence in one self-contained HTML file Make a small animated scene: a road junction with a traffic light. 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): `{light: <the light showing now, one of the spec.json phase names>, cars: [{x}, ...]}`. Extra fields are fine. It must describe what is actually drawn. - Cars drive left to right along one lane; `x` is the front of the car in stage pixels and may wrap back to the left edge after a car leaves the stage. The light runs through `phases` in the order given, starting at the first phase on load, each for its `s` seconds, then repeats. Cars may only cross `stop_line_x` on green; on any other phase they stop at the line or queue behind the car ahead. Keep the traffic dense enough that a car is waiting at the line during the non-green phases. - 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. `light_sequence`: over 3 s `sceneState().light` only takes spec.json phase names, changes only to the next phase in spec.json order (wrapping round), changes at least 3 times, and every phase seen from its start to its end lasts its `s` seconds within 0.25 s. 5. `cars_obey_lights`: `cars` has exactly spec.json `cars` entries; between two samples a car's x only goes from below `stop_line_x` to at or above it when the light is green in one of the two samples; some car moves while the light stays green, and some car waits (moves under 0.5 px) within 60 px before the stop line while the light stays on a phase other than green. 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 road junction with a traffic light 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, the scene follows a timed specification (light sequence; cars obey 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 light_sequence cars_obey_lights no_console_errors

Setup notes: Batch 29 case h08-traffic-light-junction (offline, synthetic inputs, seed 126922321). 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 0.63 (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-haiku-5.5: $0.016725. 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: $0.02
Wall time: 2m
Human step-ins: 0
Turns: 9

Model usage
Model	Input tok	Output tok	Cost
AClaude Haiku 5.5anthropic/claude-haiku-5.5effort default (no --effort flag) · thinking on	283,209	17,877	$0.02

Reproduce this run

Use the use case prompt on the use case page.
Same setup: Claude Haiku 5.5 (anthropic/claude-haiku-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 light_sequence cars_obey_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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  "result": "I wrote `out/scene.html`, a self-contained 720\u00d7480 canvas scene of a junction. A headless Chrome run of the page passed my own approximations of checks 3\u20136. I didn't run the official checker, and I didn't measure the file-load network check beyond confirming the file has no URLs.\n\n**Verified in headless Chrome (real time, sampled every ~20 ms for 4 s):**\n- **Light sequence:** the phases ran red 890 ms, red_amber 302 ms, green 906 ms, amber 483 ms, then repeated, all within the 0.25 s tolerance of spec.\n- **Cars obey lights:** zero violations of the stop-line rule. Cars moved on green (285 moving samples) and queued without moving on other phases (284 waiting samples within 60 px of the line).\n- **Errors:** no page errors or `console.error` calls.\n- **Size and references:** 4,688 bytes, with no external URLs, scripts or images.\n\n**Not checked:** the `has_canvas_or_svg` size and frame-difference thresholds, since I did not run the screenshot comparison.\n\n**Choices I made:**\n- Light timing is computed from `performance.now()` modulo the 2.6 s cycle, so the light and the drawn frame always agree.\n- Cars move at 120 px/s and keep a 54 px front-to-front gap. On any non-green phase a car stops at x = 398, one pixel short of the line, so it can never cross there.\n- Five cars start queued at the line on red. A car that leaves the right edge wraps to the back of the queue.\n- The phase names and parameters are hard-coded to match spec.json, since the page can't read the file over `file://`.\n- `sceneState()` also returns `stop_line_x`. It is an extra field, which the contract allows.",
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  "time_to_request_ms": 252,
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 }
]