> ## Documentation Index
> Fetch the complete documentation index at: https://docs.neuro-tech.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Smart contracts

> Learn how templates, parties, roles, parameters, and signatures form a contract

A Neuro smart contract is a structured agreement. Its machine-readable parts, human-readable text, participating parties, roles, parameters, signatures, and lifecycle rules must describe the same intended agreement.

## Template and instance

```text theme={null}
Template
  ├── allowed parameters
  ├── roles and parts
  ├── human-readable rendering
  └── optional lifecycle or state-machine rules
          ↓ instantiate
Contract instance
  ├── concrete parameter values
  ├── identified parties in roles
  ├── proposal and signature state
  └── current lifecycle state
```

Template approval and contract signing are different states. An approved template can be instantiated, but an instance is not a completed agreement until its own participation and signature requirements have been satisfied.

## Application responsibilities

* Use a template whose approval and compatibility are confirmed for the target Neuron.
* Bind Legal Identities to the intended parties and roles.
* Validate parameters before presenting human-readable text for signature.
* Persist the contract identifier and current proposal/signature state.
* Display the same material terms the application submits.
* Treat proposal, signature, and finalization as lifecycle states, not one synchronous request.
* Retrieve and verify the final contract rather than assuming the last command completed the workflow.

## Learn, build, reference

* **Overview:** [Agreements](/build/agreements/overview)
* **Quickstart:** [Contracts quickstart](/contracts/quickstart)
* **Guides:** [Agent API contract guide](/contracts/agent-api-quickstart)
* **Concepts:** [Templates and instances](/contracts/templates-and-instances), [roles and parts](/contracts/roles-and-parts), and [lifecycle](/contracts/lifecycle)
* **Reference:** [Contract operations](/neuron-api/api-reference/contracts/overview)