# Can I test a self-hosted decision model against Tessary's frustration classifier before switching?

Yes. Tessary can run a second, self-hosted decision model in shadow beside whichever provider is already scoring frustration, sending it the same turns and storing both verdicts side by side, with nothing a user sees changing. Every turn the live provider scores gets re-sent to the shadow exactly as the provider saw it, and the comparison is a straight count: how often the shadow's flag agrees with the provider's on the same turns.

The shadow doesn't need to be up all the time either. A connection failure or server error on its end just leaves that turn's comparison for the next pass, and an outright refusal from the shadow is recorded as a refusal rather than resent forever, so a server that sleeps most of the day doesn't pile up retries.

That's the harness for answering whether [a self-hosted System One model](/answers/system-one-models/what-is-a-system-one-model) is ready to take over from a hosted provider, on your own traffic, before anything about production actually changes.

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Sources:
- Tessary self-hosting configuration docs, "Frustration shadow model": https://docs.tessary.ai/self-hosting/configuration (fetched 2026-10-06)

Source: https://tessary.ai/answers/tessary-frustration/can-i-shadow-test-a-self-hosted-model-against-frustration
More on Tessary frustration: https://tessary.ai/answers/tessary-frustration
From Tessary, agent reliability for AI agents in production: https://tessary.ai