The Model Spec specifies desired behavior for the models underlying OpenAI's products, including our APIs (see https://github.com/openai/model_spec). The Model Spec Evals is an evaluation suite consisting of:

• a collection of evaluation prompts that measure a candidate model's adherence to the full Model Spec
• code to run the evaluations using the Inspect AI framework.

This repo expects the prompt dataset from the companion repo: Model Spec Eval Dataset. Please check out that repo and point dataset_dir at its dataset/ directory when running evals.

• Prerequisites: Python 3.10+ and an OpenAI API key available via the OPENAI_API_KEY environment variable.
• Create a virtual environment
  • macOS/Linux: python3 -m venv .venv
  • Windows (PowerShell): py -3 -m venv .venv
• Activate the environment:
  • macOS/Linux: source .venv/bin/activate
  • Windows (PowerShell): .venv\Scripts\Activate.ps1
• Install dependencies: python -m pip install --upgrade pip && pip install -r requirements.txt

To run the full suite, run the following command from this directory (replace /path/to/model_spec_dataset/dataset with your local path):

inspect eval src/model_spec_evals/tasks.py --model openai/gpt-4o-mini --display rich -T dataset_dir=/path/to/model_spec_dataset/dataset

If Inspect still reports that it cannot find any tasks, double-check that the editable install completed successfully (pip install -r requirements.txt) and that you are running inside the activated virtual environment. Note: without --display rich, the default is --display full and the TUI is known to crash when there are too many samples. You will see output after the run like this:

╭────────────────────────────────────────────────────────────────────────────────────╮
│ model_spec_evals (587 samples): openai/gpt-4o-mini                                 │
╰────────────────────────────────────────────────────────────────────────────────────╯
dataset_dir: ~/code/model_spec_dataset/dataset
total time: 0:39:58
openai/gpt-4o-mini 258,737 tokens [I: 49,788, CW: 0, CR: 0, O: 208,949, R: 0]
openai/gpt-5 33,338,551 tokens [I: 32,778,942, CW: 0, CR: 0, O: 559,609, R: 450,304]

model_graded_spec_section_compliance
style 0.703
chain_of_command 0.667
best_work 0.393
seek_truth 0.667
stay_in_bounds 0.611
all 0.622

Log: logs/2026-02-03T13-11-08-05-00_model-spec-evals_eKyMRnoVdZJYKKxx29eCjQ.eval

This reports the compliance rate for each top-level section, as well as all which is the compliance rate over the entire spec. It also reports token usage for both the candidate model (--model, here openai/gpt-4o-mini) and the grader model (-T grader_model, default openai/gpt-5), which is why both model names appear.

By default, this only runs a single epoch (sample per candidate model) and a single grader sample. Increase the number of samples from the candidate model with e.g., --epochs 10, which are averaged over. Increase the number of grader samples (from which we take the median) with e.g., -T num_grader_samples=5. One can also specify a different model to use for the grader, e.g. -T grader_model=openai/gpt-5.

You can additionally filter on sections (-T section_filter=chain_of_command,avoid_errors) and focus ids (-T focus_filter=8ep1,adau). The standard Inspect CLI argument can be used to filter by prompt id, i.e., --sample-id 46b7a94e-feb9-440f-bea1-537c474a914f,d7b36bdd-339a-47dd-8999-263acddd61ad,dd9afa72-c9cf-4944-8fe6-3f6e3970c01f,9e9cb7b8-6b1c-4735-95c0-1a87cc8d1937.

The results reported in our blog post were obtained by sampling the target model 20 times on each prompt, and for each target model sample we sample the grader model 5 times and take the median. Note that the results may not be fully reproducible because some prompts are skipped because the OpenAI API only supports developer messages for newer models. However, while the absolute scores may not be reproducible, directionality between models should roughly be reproducible. To reproduce the blog-post setting, use --epochs 20 and -T num_grader_samples=5. For example, running with openai/gpt-5:

inspect eval src/model_spec_evals/tasks.py \
  --model openai/gpt-5 \
  --display rich \
  --epochs 20 \
  -T dataset_dir=/path/to/model_spec_dataset/dataset \
  -T num_grader_samples=5 \
  -T grader_model=openai/gpt-5

To launch the Inspect log viewer for local results:

inspect view start

The command output will print a URL; open that URL in your browser.