> ## 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.

# Tier 1: Error Decoding

> Resolving cryptic errors into plain English.

Tier 1 is the fastest way to understand why a transaction failed. Prism takes the transaction result XDR and performs a multi-step enrichment process.

## How it works

1. **Classification**: Prism extracts the `TransactionResult` and identifies the specific error code.
2. **Taxonomy Lookup**: It maps the code to our [Error Taxonomy](/concepts/error-taxonomy), which contains detailed explanations for every host error.
3. **Contract Resolution**: If the error is a custom contract error (`Error(Contract, #N)`), Prism:
   * Fetches the contract's WASM bytecode from the ledger.
   * Parses the `contractspecv0` custom section.
   * Cross-references the error index with the defined enum names and doc comments.

## Contract-Specific Metadata

Prism resolves `#3` into `InsufficientBalance` because it understands the contract's metadata structure. This turns a generic number into a business-logic error that you can fix instantly.

## Plain-English Error Summaries

Every `HostError` exposes a `summary()` method that returns a single sentence
describing what went wrong. This is the **first line** a developer sees when
running `prism decode` — written to immediately answer "what went wrong?" without
requiring knowledge of Soroban internals.

### Examples

| Error              | Summary                                                                                                              |
| ------------------ | -------------------------------------------------------------------------------------------------------------------- |
| `Budget(0)`        | CPU budget exceeded: the transaction ran out of CPU instructions before completing execution.                        |
| `Storage(0)`       | Storage access denied: the contract tried to read or write a ledger entry not declared in the transaction footprint. |
| `Auth(0)`          | Authorization failed: the transaction is missing or has invalid auth entries for this contract call.                 |
| `Wasm(0)`          | Invalid WASM module: the contract bytecode failed validation — recompile with a compatible Soroban SDK version.      |
| `ContractSpecific` | Always points toward `--resolve` for WASM metadata lookup.                                                           |
| `Unknown`          | Includes raw type and sub-codes for forward-compatibility debugging.                                                 |

All summaries are kept under 120 characters and avoid technical jargon where possible.
For unknown codes within known categories, a formatted fallback is returned so no
error is ever left unexplained.