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

# Error Handling

> Handle errors from @cofhe/sdk operations using typed CofheError objects

All SDK operations return values directly and throw typed `CofheError` objects on failure. This replaces the `Result` wrapper pattern used by `cofhejs`.

## Catching errors

```typescript theme={null}
import { isCofheError, CofheErrorCode, Encryptable } from '@cofhe/sdk';

try {
  const [encrypted] = await client
    .encryptInputs([Encryptable.uint32(42n)])
    .execute();
} catch (err) {
  if (isCofheError(err)) {
    console.error(err.code);    // CofheErrorCode enum value
    console.error(err.message); // human-readable description
  }
}
```

## CofheError structure

Every `CofheError` has:

* `code` — a `CofheErrorCode` enum value identifying the error type
* `message` — a human-readable description of what went wrong

Use `isCofheError(err)` to check if a caught error is a `CofheError`.

## Common error codes

| Error code       | When it occurs                                              |
| ---------------- | ----------------------------------------------------------- |
| `ZkPackFailed`   | `encryptInputs` exceeded the 2048-bit plaintext limit       |
| `PermitNotFound` | No permit found for the given `chainId + account`           |
| `PermitInvalid`  | The permit signature is invalid or expired                  |
| `DecryptFailed`  | Decryption request was rejected by the Threshold Network    |
| `NotConnected`   | Attempted an operation before calling `client.connect(...)` |

## Error handling patterns

### Encryption errors

```typescript theme={null}
import { isCofheError, CofheErrorCode, Encryptable } from '@cofhe/sdk';

try {
  const encrypted = await client
    .encryptInputs([Encryptable.uint128(veryLargeValue)])
    .execute();
} catch (err) {
  if (isCofheError(err) && err.code === CofheErrorCode.ZkPackFailed) {
    console.error('Input too large — split into multiple calls');
  }
}
```

### Decryption errors

```typescript theme={null}
import { isCofheError, CofheErrorCode, FheTypes } from '@cofhe/sdk';

try {
  const plaintext = await client
    .decryptForView(ctHash, FheTypes.Uint32)
    .execute();
} catch (err) {
  if (isCofheError(err) && err.code === CofheErrorCode.PermitNotFound) {
    // Create a permit and retry
    await client.permits.getOrCreateSelfPermit();
    const plaintext = await client
      .decryptForView(ctHash, FheTypes.Uint32)
      .execute();
  }
}
```

### Distinguishing why a permit is invalid

Since `@cofhe/sdk@0.5.0`, the decrypt flows call `PermitUtils.validate(permit)` internally before talking to the Threshold Network. That helper enforces **schema + signed + not-expired** all at once, so when it fails the recovery path depends on **which** check tripped.

Use the non-throwing `ValidationUtils.isValid` helper from `@cofhe/sdk/permits` to pre-flight the active permit and route based on the typed reason — this avoids the thrown error path entirely:

```typescript theme={null}
import { FheTypes } from '@cofhe/sdk';
import { ValidationUtils } from '@cofhe/sdk/permits';

const active = client.permits.getActivePermit();
const result = active
  ? ValidationUtils.isValid(active)
  : { valid: false, error: 'not-signed' as const };

if (!result.valid) {
  switch (result.error) {
    case 'expired':
      await client.permits.getOrCreateSelfPermit(); // create a fresh one
      break;
    case 'not-signed':
      await client.permits.getOrCreateSelfPermit(); // prompt the wallet to sign
      break;
    case 'invalid-schema':
      client.permits.removeActivePermit(); // stored payload is malformed
      break;
  }
}

const plaintext = await client
  .decryptForView(ctHash, FheTypes.Uint32)
  .execute();
```

`ValidationResult.error` is the typed union `'invalid-schema' | 'expired' | 'not-signed' | null` — see [Permits → Validating permits](/client-sdk/guides/permits#validating-permits) for the full helper surface.

<Note>
  If you prefer the throwing path: `PermitUtils.validate(permit)` raises plain `Error`s with messages `Permit is expired` / `Permit is not signed` (or a Zod schema error). These are not wrapped in `CofheError`, so use `err.message` rather than an error code to branch.
</Note>