Claude Sonnet 5.5 (effort default (no --effort flag) · thinking on) on Add HTTP byte-range support to a stdlib file server (single, suffix, multipart, 416, If-Range, HEAD)
AClaude Sonnet 5.5default · thinking on · Claude Code 2.1.299 (headless -p) · cloud · 2026-10-19 · by @bobsiopener
- Estimated cost
- $0.07
- Wall time
- 18s
- Human step-ins
- 0
- Outcome
- Pass
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Summary
Exact prompt
# Task: add byte-range support to the file server `server.py` serves the files under `public/` but ignores the `Range` and `If-Range` request headers, so downloads cannot resume and media players cannot seek. Change `server.py` so it implements `RANGES.md` exactly. Everything it already does correctly (paths, 404s, content types) must keep working. Do not change anything under `public/` (the grader checks those files are byte-identical to the originals). Python standard library only. Keep the command line: `python3 server.py [port]`, port also from env `G02_PORT`, default 18702, bind 127.0.0.1. No network beyond localhost. The grader starts your server, sends requests with `http.client`, compares status codes, the headers named in RANGES.md and the exact body bytes, then stops the server.
Exact status/header/body checks for clamping, suffix ranges, unsatisfiable vs malformed headers (416 vs ignore), un-merged multipart bodies with a fixed boundary, ETag-gated If-Range and HEAD parity. 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: 1. public_files_unchanged: files under public/ are byte-identical. 2. full_response_headers: 200 carries Accept-Ranges and the SHA-256-prefix ETag. 3. single_ranges: first-last, first-, -suffix, clamped last, oversize suffix, spaces, correct Content-Type. 4. unsatisfiable_416: 416 with bytes */size for 5 unsatisfiable headers incl. empty file. 5. malformed_range_ignored: 8 malformed headers give a plain 200. 6. multipart_byteranges: exact multipart body, order kept, overlaps not merged, unsatisfiable parts dropped, single survivor gives a single-part 206. 7. if_range: matching ETag honours Range, mismatching/unquoted gives 200, If-Range alone changes nothing. 8. head_requests: HEAD mirrors GET status/headers without body. 9. errors_unaffected: missing files still 404.
Setup notes: Use Case Scout batch 7 case g02-http-range-requests (offline fixture). Prepared with batch7/prepare.sh; hidden key/tests kept outside the agent's work dir. Prompt = TASK.md verbatim. Scored with the scout's scorer: `python score.py WORKDIR KEYDIR`. Tools: Read/Write/Edit/Glob/Grep/Bash, web disabled. Single run, no retries. 1-min load average at scoring: 1.57. Claude Code's own reported cost for claude-sonnet-5.5: $0.072271. Score: 9/9 checks. 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
- $0.07
- Wall time
- 18s
- Human step-ins
- 0
- Turns
- 5
| Model | Input tok | Output tok | Cost |
|---|---|---|---|
| AClaude Sonnet 5.5anthropic/claude-sonnet-5.5effort default (no --effort flag) · thinking on | 62,146 | 2,396 | $0.07 |
Reproduce this run
- Use the use case prompt on the use case page.
- 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. - It counts as a success only if it meets every success criterion: 1. public_files_unchanged: files under public/ are byte-identical. 2. full_response_headers: 200 carries Accept-Ranges and the SHA-256-prefix ETag. 3. single_ranges: first-last, first-, -suffix, clamped last, oversize suffix, spaces, correct Content-Type. 4. unsatisfiable_416: 416 with bytes */size for 5 unsatisfiable headers incl. empty file. 5. malformed_range_ignored: 8 malformed headers give a plain 200. 6. multipart_byteranges: exact multipart body, order kept, overlaps not merged, unsatisfiable parts dropped, single survivor gives a single-part 206. 7. if_range: matching ETag honours Range, mismatching/unquoted gives 200, If-Range alone changes nothing. 8. head_requests: HEAD mirrors GET status/headers without body. 9. errors_unaffected: missing files still 404.
- 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
[
{
"duration_api_ms": 15844,
"stop_reason": "end_turn",
"session_id": "[REDACTED]",
"total_cost_usd": 0.0722709,
"usage": {
"input_tokens": 6,
"cache_creation_input_tokens": 10791,
"cache_read_input_tokens": 51349,
"output_tokens": 2396,
"output_tokens_details": {
"thinking_tokens": 230
},
"server_tool_use": {
"web_search_requests": 0,
"web_fetch_requests": 0
},
"service_tier": "standard",
"cache_creation": {
"ephemeral_1h_input_tokens": 10791,
"ephemeral_5m_input_tokens": 0
},
"inference_geo": "global",
"iterations": [
{
"input_tokens": 2,
"output_tokens": 393,
"cache_read_input_tokens": 20705,
"cache_creation_input_tokens": 2625,
"cache_creation": {
"ephemeral_5m_input_tokens": 0,
"ephemeral_1h_input_tokens": 2625
},
"type": "message"
}
],
"speed": "standard",
"fallback_credit": null
},
"modelUsage": {
"claude-sonnet-5-5": {
"inputTokens": 6,
"outputTokens": 2396,
"cacheReadInputTokens": 51349,
"cacheCreationInputTokens": 10791,
"webSearchRequests": 0,
"costUSD": 0.0722709,
"contextWindow": 1000000,
"maxOutputTokens": 128000,
"thinkingTokens": 230,
"canonicalModel": "claude-sonnet-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": 5,
"subtype": "success",
"api_error_status": null,
"result": "`server.py` now handles `Range` and `If-Range` as `RANGES.md` describes. I only spot-checked it on `hello.txt` with five requests, and every response matched the spec:\n\n- **Single range:** `bytes=0-4` returned 206 with `Content-Range: bytes 0-4/37`.\n- **Several ranges:** `bytes= -3 , 5-6` returned a multipart 206 with the `G02BOUNDARY` body.\n- **Unsatisfiable range:** `bytes=99-` returned 416 with `Content-Range: bytes */37`.\n- **Malformed range:** `bytes=2-1` on a `HEAD` request returned 200 with the full `Content-Length` and no body.\n- **Stale validator:** a `Range` request with a wrong `If-Range` returned 200 with the full file.\n\nI didn't test `data.bin`, `empty.txt`, `sub/page.html`, a 404, or a correct `If-Range`. I also didn't run the earlier 200 and 404 paths separately, though that code is unchanged apart from the new headers.\n\nNothing under `public/` was touched, and the command line, port handling and localhost binding are as before.",
"ttft_ms": 1362,
"type": "result",
"duration_ms": 17436,
"uuid": "[REDACTED]",
"ttft_stream_ms": 1028,
"time_to_request_ms": 456,
"first_content_frame_ms": 1028,
"queued_turn_count": 0,
"result_index": 0
}
]