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agentix.cassette

cassette

Record/replay cassettes for deterministic real-model tests.

Hitting a live model in tests is slow, costly, and flaky. :class:CassetteModel wraps any model: the first run records each model call's response to a JSON file; later runs replay from the file with no network. Same idea as VCR — record once, replay forever (delete the file to re-record).

model = CassetteModel("tests/cassettes/weather.json", model=AnthropicModel())
agent = Agent(model=model, system_prompt="...", tools=[...])
outcome = await agent.run("...")
model.save()   # writes the cassette in record mode (no-op when replaying)

With mode="auto" (the default) it records when the file is missing and replays when it exists. Replay is sequential: responses are returned in the order they were recorded, matching a deterministic loop.

CassetteModel 

CassetteModel(
    path: str,
    model: ModelFn | None = None,
    *,
    mode: Mode = "auto",
)

A :class:~agentix.model.ModelFn that records/replays model responses.

mode: "auto" (record if the file is missing, else replay), "record" (wrap model and capture), or "replay" (read from the file; no model needed). Call :meth:save after a recording run to write the file.

save 

save() -> None

Write the recorded interactions (no-op in replay mode).