> ## Documentation Index
> Fetch the complete documentation index at: https://prism-ddf93e61.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Core Library

> Embed Prism diagnostics into your own tools.

The Prism core engine is published as a Rust crate and a WASM package.

## Rust Usage

Add `prism-core` to your `Cargo.toml`:

```toml theme={null}
[dependencies]
prism-core = "0.1.0"
```

## WASM Usage

Embed Prism into your JavaScript/TypeScript applications:

```bash theme={null}
npm install @prism-soroban/wasm
```

## Public API Highlights

* `decode_error`: Returns a structured diagnostic report.
* `resolve_contract_error`: Decodes custom error codes via WASM.
* `replay_transaction`: Runs a full Tier 2/3 simulation.

## HostError API

The `HostError` enum is the central type the decode engine works with.
It covers every Soroban host error category, contract-specific errors,
and an `Unknown` variant for forward compatibility.

### `summary() -> String`

Returns a one-line plain-English sentence explaining what went wrong.
This is the headline shown by `prism decode` — the first thing a developer
reads when diagnosing a failed transaction.

```rust theme={null}
use prism_core::decode::host_error::HostError;

let err = HostError::Budget { code: 0 };
println!("{}", err.summary());
// → "CPU budget exceeded: the transaction ran out of CPU instructions before completing execution."

let err = HostError::ContractSpecific {
    contract_id: Some("CABC123...".to_string()),
    code: 3,
};
println!("{}", err.summary());
// → "Contract-specific error 3 from CABC123...: run with --resolve to look up the error name from the contract's WASM metadata."
```

**Behaviour guarantees:**

* Every variant returns a non-empty string — no error is ever silent.
* Known code `0` summaries are under 120 characters.
* Unknown codes within known categories fall back to a formatted message including the code number.
* `ContractSpecific` always mentions `--resolve` to guide the developer to the next step.
* `Unknown` always includes both `type_code` and `sub_code` for diagnostic purposes.

### `category_name() -> &str`

Returns the human-readable category name for the error variant,
e.g. `"Budget"`, `"Auth"`, `"ContractSpecific"`.