01What Courant is
Courant watches a computational fluid dynamics run, names the likely cause when it fails or produces a physically suspect result, proposes a bounded repair, re-runs the case, verifies the physics with deterministic checks, and writes an evidenced report.
It is delivered as an agent you run on your own machines together with a hosted service. The first supported solver is OpenFOAM.
These terms are between you — or the organisation whose account you are using — and Courant. Using the agent, the service or this website means accepting them.
02What it changes, and what it will not touch
Courant edits a fixed, published set of dictionary parameters and nothing else: a timestep, a relaxation factor, a discretisation scheme, a solver tolerance, a write interval.
- It will not edit your mesh.
- It will not edit boundary conditions.
- It will not edit geometry.
- It will not edit solution fields.
- It will not delete anything.
Every change is applied to a copy and dry-run parsed before it touches your case, a backup is taken before anything is written, and one command reverts the last applied change.
03Who decides
In copilot mode nothing is applied without your approval. In autopilot mode changes within the permitted set are applied automatically — that mode is yours to choose and yours to turn off, and the permitted set does not widen when you enable it.
Where the leading cause has no permitted repair — a broken mesh, most boundary-condition errors, a modelling choice — Courant applies nothing and says so. 'No safe automatic fix' is a result, not a failure, and a run whose real problem could not be repaired is not reported as fixed because something lesser was.
04What a diagnosis is worth
A diagnosis is a ranked hypothesis with the evidence that produced it. It is not a warranty that the named cause is the actual cause, and a Trust Grade is not a certification that a simulation is correct.
Measured against real solver output, the deterministic engine names the true cause first about eight times in ten and within its top two on every case in our published corpus. Those numbers are published and reproducible. They are a description of that corpus, not a prediction about your case.
Verification checks what can be checked from a solve: whether residuals converged, whether the Courant number respected the criterion that applies to that case, whether transported quantities stayed bounded, whether boundary fluxes balance. It cannot check whether you modelled the right problem, chose the right closure, or meshed the right geometry.
You remain the engineer. Do not use Courant as the sole basis for a decision about a physical system, a safety case, or a regulatory submission.
05Your account
Sign-in is by emailed link or by approving a device; there is no password to lose. You are responsible for who can read the mailbox and who can use the machines you enrol.
You may invite others into your organisation. An invitation is bound to the address it was sent to, so forwarding one does not admit whoever opens it.
Tell us promptly if you believe an account or an enrolled machine has been compromised.
06Your data and your work
You keep every right in your own data. We claim no licence over your cases, your results or your reports beyond what is needed to run the service you asked for.
We do not train models on your data, and the sub-processor we send an Evidence Bundle to is instructed not to either.
What crosses the network, and what never does, is set out in the Privacy Policy and is part of these terms by reference.
07What it costs
Paid plans open on 10 September 2026. Until then every account is a pilot account: no payment method is collected and no charge is made.
When paid plans open, one engineer is free, a team is priced per engineer per month, and regulated or air-gapped deployments are priced individually. Current pricing is on the plans page, and any change will be announced to account holders before it takes effect.
Nothing on this website is an offer to contract. A contract forms when terms are presented to you at the point of purchase and you accept them.
08Availability
We do not offer an uptime commitment during the pilot period and will not pretend otherwise. What we offer instead is that the agent degrades rather than fails: with the service unreachable it keeps watching the run, diagnoses locally with the deterministic engine, and queues what it could not send.
The bundled demo runs the whole loop with no account and no network.
We may change the service as it develops. Where a change removes something you rely on, we will say so before it happens.
09Acceptable use
Do not attack, overload or attempt to reverse-engineer the service. Do not use it to process data you have no right to process. Do not resell access without agreement.
We may suspend an account doing one of those things, and we will tell you why.
10Liability
The service is provided as-is and as-available. To the fullest extent the law allows, we exclude liability for indirect or consequential loss, for lost profit, and for decisions taken on the basis of a diagnosis, a fix or a Trust Grade.
Nothing in these terms limits liability for death or personal injury caused by negligence, for fraud, or for anything else that cannot lawfully be limited.
The governing law and venue are not yet stated — see the document status note at the foot of this page.
11Ending it
You can stop using Courant at any time and delete your account, which deletes its runs, diagnoses, fixes, verifications and reports. Export anything you want to keep first.
We may end an account for a serious or repeated breach of these terms, with notice and with a reason. If we end it for any other reason we will give you reasonable notice and refund anything paid for a period you no longer get.
12Changes to these terms
When these terms change materially we will email account holders before the change takes effect, and the version and date at the top of this page will move. Continuing to use the service after that date is acceptance of the change.
If you do not accept a change, you may close your account before it takes effect.