| --- |
| license: mit |
| language: |
| - en |
| pretty_name: fixture-entropy |
| size_categories: |
| - 1K<n<10K |
| task_categories: |
| - text-generation |
| tags: |
| - llm-evaluation |
| - test-data |
| - diversity |
| - claude |
| - synthetic |
| configs: |
| - config_name: calls |
| data_files: |
| - split: train |
| path: out/calls.jsonl |
| --- |
| |
| # fixture-entropy |
|
|
| Author: Dmitriy Semenkevich (dimhold) |
|
|
| This dataset measures how often 2 independent test fixture sets generated by a Claude model share a value, for 7 value types across 7 Anthropic models, against Faker and true random baselines. |
|
|
| Headline, from the repository README: "Ask a Claude model twice for 30 test person names and the 2 lists share at least 1 name in 64 to 98% of pairs, depending on the model. Faker at the same size: 1.29%." |
|
|
| This is a mirror. The canonical home is the Zenodo record and the GitHub repository; the registration, prior work, limitations and full tables live there. |
|
|
| - Paper: https://dimhold.by/papers/fixture-entropy/ |
| - Code and full write up: https://github.com/dimhold/fixture-entropy |
| - DOI: https://doi.org/10.5281/zenodo.23545744 |
|
|
| ## Files |
|
|
| | path | what it is | |
| |---|---| |
| | `out/calls.jsonl` | every call: prompt, full reply, usage, timing (1366 rows: 1274 main, 66 n100, 26 failed and retried) | |
| | `out/baseline.json` | Faker, `uuid4` and `random` baseline values used in all tables | |
| | `out/summary-main.json` | per cell statistics from `report.py` | |
| | `out/report-main.md` | the same as tables | |
| | `out/extra-main.txt` | pooled rates, valid UUID recount, frequency lists, n100 pilot (`extra_stats.py`) | |
| | `out/logs/` | run logs | |
| | `context-check.json` | what the CLI could load from the environment | |
|
|
| The names, emails, usernames, companies and addresses in the replies are invented by the models; they are the measured data, not real people. |
|
|
| ## How it was produced |
|
|
| 1274 calls through Claude Code CLI 2.1.302 between 19 and 20 October 2026, each a separate process with no history, from an empty directory with tools, MCP servers and user settings disabled. 7 types, 3 arms (`plain`, `json`, `diverse`), 7 models. The model reported in `modelUsage` matched the one requested in all 1274. Rows with `"ok": false` are failed attempts that were retried. The n100 phase is incomplete and excluded from every conclusion. For publication the local user directory, the clean room path, the account email and a city in 1 reply were replaced with placeholders; nothing else in the journal was changed. Scripts that reproduce every number are in the GitHub repository. |
|
|
| ## Licence |
|
|
| MIT, code and data alike. |
|
|
| ## Citation |
|
|
| ```bibtex |
| @misc{semenkevich2026fixtureentropy, |
| author = {Semenkevich, Dmitriy}, |
| title = {fixture-entropy: how often 2 LLM generated test fixtures collide}, |
| year = {2026}, |
| doi = {10.5281/zenodo.23545744}, |
| url = {https://doi.org/10.5281/zenodo.23545744} |
| } |
| ``` |
|
|
