Treat an AI agent's root cause as a hypothesis with evidence attached, and trust it as far as the evidence goes. A reproduced failure and a direct match in the error trace count as evidence. A model's confident wording does not.
What a root cause assessment contains
A sound assessment has five parts: the hypothesis, the evidence that supports it, the evidence that contradicts it, what is missing, and the next step. The contradicting evidence matters most. An assessment that lists only support has not looked for a reason to be wrong.
Four states, not one verdict
SylvieSI gives each assessment one of four states. Verified: a reproduction passed or the error trace matches directly, and a person confirmed it. Probable: the evidence points to a cause but does not establish it. Insufficient evidence: there is not enough to judge, and the Case lists what is missing. Unable to determine: the cause could not be established with the information and permissions available.
A model's wording can reach Probable at most. Verified needs evidence and a person.
Why a model's confidence is not evidence
A language model writes fluent explanations whether or not they are right. A fluent cause is easy to believe, so the check has to sit outside the model. In SylvieSI, certainty is computed from what was found: whether the bug was reproduced, whether the trace matches, how fresh the sources are and whether anything contradicts the cause.
What to check before you accept a cause
Four checks take a few minutes. Did the reproduction pass, and can you see the steps? Does every claim cite a source that exists, and is the source recent? Was the contradicting evidence addressed? Is anything listed as missing that you could supply? If a cause fails any of these, it is a lead, not a cause.
When the answer is "unable to determine"
A result of "unable to determine" is a useful result when it says why. The assessment names what was missing: a tool that is not connected, error data that is out of date, access that was not granted. The Case stays open with a blocked item that names what is needed, and nobody ships a fix for a cause nobody found.