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Claude Sonnet 5.5 (effort default (no --effort flag) · thinking on) on Build a leg model from a PDF datasheet that keeps to its real dimensions, servo limits and kinematics

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

Trust 80%Fully autonomoussuccess · first try
Estimated cost
$0.06
Wall time
20s
Human step-ins
0
Outcome
Pass

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Summary

Exact prompt

# Build a leg model from a PDF datasheet that keeps to its real dimensions and limits Inputs: `datasheet.pdf` (a synthetic datasheet for a mock hexapod leg module; `pdftotext -layout datasheet.pdf -` reads it), `poses.json` (servo commands) and `targets.json` (foot targets in the body frame, mm). The datasheet is the record, including any errata it contains. Rules: - Link lengths come from the datasheet in mm (convert inches at 25.4 mm per inch); an erratum replaces the value it corrects. - Joint angles: coxa yaw θ1 = coxa servo − its centre; femur pitch θ2 = femur servo − its horizontal reading, negated if the datasheet says increasing the servo lowers the femur; knee bend k = 180 − tibia servo. Joint limits are the servo stops mapped this way, each written as [low, high]. - Foot position in the leg frame: r = coxa + femur·cos θ2 + tibia·cos(θ2 − k), z = femur·sin θ2 + tibia·sin(θ2 − k), x = r·cos θ1, y = r·sin θ1. The leg frame's origin is the coxa joint, which sits at the datasheet's mount offset in the body frame (body = leg + offset, same axes). - For each target, solve for the unique servo commands with the knee bent (k between 0 and 180) that put the foot there, or mark it "unreachable" if it is out of reach or any servo would pass a stop. - Report servo angles in degrees rounded to 0.01 and positions in mm rounded to 0.01 (servo angles are compared to within 0.02). - Write `out/leg.json`: `{"links_mm": {"coxa": <mm>, "femur": <mm>, "tibia": <mm>}, "joint_limits_deg": {"coxa": [lo, hi], "femur": [lo, hi], "knee": [lo, hi]}, "poses": {"<pose id>": [x, y, z], ...} (foot in the body frame), "ik": {"<target id>": {"coxa": <servo>, "femur": <servo>, "tibia": <servo>} or "unreachable", ...}}`. ## 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.

Read a synthetic PDF datasheet for a mock hexapod leg and turn it into a working model: link lengths (one in inches, one corrected by an erratum on the second page), joint limits mapped from servo stops with a centre offset, a horizontal reading and a direction note, forward kinematics for given servo poses in the body frame with a mount offset, and inverse kinematics for foot targets including one out of reach and one that would pass a servo stop. 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: links joint_limits forward_kinematics ik_reachable ik_unreachable

Setup notes: Batch 32 case te03-datasheet-leg-model (offline, synthetic inputs, seed 2137623773). 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 0.66 (8 cores). Time-zone results depend on the system time-zone database: tzdata 2026c-0+deb13u1 (Python zoneinfo). Claude Code's own reported cost for claude-sonnet-5.5: $0.059093. Score: 5/5. 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.

Metrics

Estimated cost
$0.06
Wall time
20s
Human step-ins
0
Turns
3
Model usage
ModelInput tokOutput tokCost
AClaude Sonnet 5.5anthropic/claude-sonnet-5.5effort default (no --effort flag) · thinking on59,5641,891$0.06

Reproduce this run

  1. Use the use case prompt on the use case page.
  2. Same setup: Claude Sonnet 5.5 (anthropic/claude-sonnet-5.5, effort default (no --effort flag) · thinking on) via Claude Code 2.1.299 (headless -p), cloud.
  3. It counts as a success only if it meets every success criterion: links joint_limits forward_kinematics ik_reachable ik_unreachable
  4. 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

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Evidence log
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    "canonicalModel": "claude-sonnet-5-5",
    "provider": "firstParty",
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  },
  "permission_denials": [],
  "terminal_reason": "completed",
  "fast_mode_state": "off",
  "fast_mode_disabled_reason": "sdk_opt_in_required",
  "subagent_stats": {
   "spawned": 0,
   "requested": {
    "background": 0,
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   "started_in_background": 0,
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   "completed": 0,
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   "killed": {
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   "refused": {
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  "safety_stops": 0,
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  "subtype": "success",
  "api_error_status": null,
  "result": "I wrote `out/leg.json`. The IK results look like clean round servo angles, which suggests the targets were generated from the same model. I didn't run an independent check of the file beyond that.\n\n**Link lengths (mm):**\n- **Coxa:** 48.\n- **Femur:** 78.00, from 3.0709 in.\n- **Tibia:** 141, because the Rev B erratum replaces the Rev A value of 137.\n\n**Joint limits (deg):**\n- **Coxa:** [-37, 36].\n- **Femur:** [-81, 70]. The datasheet says increasing the femur servo raises the femur, so no negation applies.\n- **Knee:** [15, 151].\n\n**Foot positions in the body frame (mm):**\n\n| Pose | x | y | z |\n|---|---|---|---|\n| P1 | 90.22 | -4.79 | -205.23 |\n| P2 | 291.00 | -16.15 | 95.33 |\n| P3 | 34.83 | 10.69 | -87.13 |\n\n**Servo commands (deg):**\n\n| Target | Coxa | Femur | Tibia |\n|---|---|---|---|\n| T1 | 84.00 | 96.01 | 149.98 |\n| T2 | 114.03 | 31.03 | 139.96 |\n| T3 | 99.01 | 138.03 | 81.99 |\n\n- **T4** is unreachable. It is at the full-stretch limit, where the knee would have to be straight.\n- **T5** is unreachable. The solution needs a coxa yaw of about -43\u00b0, which is past the coxa stop.",
  "ttft_ms": 6874,
  "type": "result",
  "duration_ms": 19511,
  "uuid": "[REDACTED]",
  "ttft_stream_ms": 6350,
  "time_to_request_ms": 341,
  "first_content_frame_ms": 6351,
  "queued_turn_count": 0,
  "result_index": 0
 }
]

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