Terms of service

Last updated 6 August 2026

These terms cover the hosted service at substructure.ai and app.substructure.ai. Using it means you accept them. The engine itself is open source and carries its own licence. Running it on your own infrastructure is not covered here.

The service

Substructure runs durable, long-running agents: it holds their sessions, executes their turns, connects them to Slack and MCP servers, and calls the webhook workers you point them at. What the service does is defined by what it does at the time you use it. We add and change features, and occasionally remove ones that are not working.

Your account

  • Give an accurate email address and keep it current. It is how we reach you.
  • You are responsible for what happens under your account and inside your organization.
  • Anyone you invite to an organization can see and act on that organization's projects. Inviting someone is a decision about your own data.
  • You must be old enough to enter a contract where you live, and at least 16.

Credits and payment

New organizations start with a block of free credits and no card required. After that you buy credits up front at a flat rate, through Stripe. Running a turn spends a credit. There is no subscription: nothing renews, and you are charged only when you buy. The current rate and the smallest purchase are on the pricing page, and those numbers are the ones that apply.

  • Limits are real. You can spend only the credits you hold. When they run out, sessions park rather than continuing, and resume when you buy more. Turns already under way finish.
  • Models are not included. You bring your own provider key and pay that provider directly. Nothing you spend on tokens passes through us, and our price does not change when your usage does.
  • Credits expire. Credits lapse 12 months after the day you buy them. When you hold several purchases, the ones nearest to lapsing are always spent first.
  • Refunds. There is nothing to cancel, because nothing renews. Ask us and we will refund credits you have not spent.
  • Price changes. A change to the rate applies to purchases made after it takes effect. Credits you have already bought are credits, not money, and are unaffected.
  • Tax. Prices exclude any sales tax or VAT that applies to you, which is added at checkout where required.

What you keep

Your projects, your agent configuration, your session history, and everything your agents produce remain yours. You grant us only the permission needed to run the service: to store that content, process it, transmit it to the providers you have connected, and back it up.

We do not use your content to train models, and we do not sell it. Export or delete it at any time, or write to support@substructure.ai and we will do it for you.

Acceptable use

Do not use the service to:

  • break the law, or help someone else break it;
  • send spam, run phishing, or impersonate someone;
  • attack, probe, or overload our infrastructure or anyone else's, including through agents you configure here;
  • build or distribute malware;
  • work around the credits you hold, through multiple accounts, shared credentials, or otherwise;
  • upload content you have no right to, or that is unlawful where you operate.

You are responsible for what your agents do. An agent acting on your instructions is you.

Services you connect

Slack, MCP servers, your model provider, and your own webhook workers are third parties. Your use of them is governed by your agreement with them, they may change or stop working, and we are not responsible for what they do with what you send. Connecting one authorizes us to send it the data that connection requires.

Availability

We do not offer a service-level agreement. The service will occasionally be unavailable, for maintenance and for reasons we did not plan. We aim to keep it running and to be honest when it is not, but we do not promise uptime, and agent runs can fail or be delayed.

Disclaimer and liability

The service is provided "as is", without warranties of any kind, express or implied, including merchantability, fitness for a particular purpose, and non-infringement. Agents are probabilistic: they make mistakes, and their output is not something to rely on unchecked in a consequential decision. Reviewing what your agents do is your responsibility.

To the fullest extent the law allows, we are not liable for indirect, incidental, special, or consequential damages, or for lost profits, revenue, or data. Our total liability for any claim relating to the service is limited to what you paid us in the twelve months before the claim arose. Some jurisdictions do not allow these limits, in which case they apply only as far as they are permitted.

Suspension and termination

You can close your account at any time. We can suspend or close an account that breaches these terms, that is not paying, or that puts the service or other users at risk, and we will tell you why unless the law prevents it. When an account closes, its data is deleted on the schedule in the privacy policy.

Changes to these terms

We will update this page when the agreement changes and move the date at the top. For material changes we will give notice by email. Continuing to use the service after a change means the updated terms apply; if you do not accept them, stop using the service and cancel.

Contact

Questions about these terms: support@substructure.ai.