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

# Observer

> Read-only methods for querying CDR vault data, fees, and DKG state.

## Observer

The `Observer` sub-client is always available, even without a `walletClient`. It provides read-only access to CDR and DKG state.

```typescript theme={null}
const observer = client.observer;
```

The Observer reads from two backends: CDR contract state (vaults, fees,
`maxEncryptedDataSize`, operational threshold) over the EVM `publicClient`, and
DKG state (active round, global public key, threshold, validators,
attestations) over the DATA Foundation API REST endpoint configured by `apiUrl`.

<Note>
  Round-keyed DKG snapshots are cached for the lifetime of the Observer for
  rounds in the stable Active and Ended stages, with in-flight request
  deduplication. `getActiveRound()` always re-fetches, since the active round
  can transition at any time.
</Note>

### Methods

* getVault
* getAllocateFee
* getWriteFee
* getReadFee
* getMaxEncryptedDataSize
* getOperationalThreshold
* getActiveRound
* getGlobalPubKey
* getParticipantCount
* getThreshold
* getThresholdAt
* getRegisteredValidators
* getValidatorAttestations

***

### getVault

Fetch a vault's on-chain data by UUID.

| Method     | Type                               |
| ---------- | ---------------------------------- |
| `getVault` | `(uuid: number) => Promise<Vault>` |

Parameters:

* `uuid`: The vault's unique identifier (uint32)

```typescript Example theme={null}
const vault = await client.observer.getVault(42);

console.log(vault.uuid); // 42
console.log(vault.updatable); // false
console.log(vault.writeConditionAddr); // "0x..."
console.log(vault.readConditionAddr); // "0x..."
console.log(vault.encryptedData); // "0x..." (hex-encoded TDH2 ciphertext)
```

```typescript Vault theme={null}
interface Vault {
  uuid: number;
  updatable: boolean;
  writeConditionAddr: `0x${string}`;
  readConditionAddr: `0x${string}`;
  writeConditionData: `0x${string}`;
  readConditionData: `0x${string}`;
  encryptedData: `0x${string}`;
}
```

***

### getAllocateFee

Returns the current fee (in wei) required to allocate a new vault.

| Method           | Type                    |
| ---------------- | ----------------------- |
| `getAllocateFee` | `() => Promise<bigint>` |

```typescript Example theme={null}
const fee = await client.observer.getAllocateFee();
console.log(`Allocate fee: ${fee} wei`);
```

***

### getWriteFee

Returns the current fee (in wei) required to write data to a vault.

| Method        | Type                    |
| ------------- | ----------------------- |
| `getWriteFee` | `() => Promise<bigint>` |

```typescript Example theme={null}
const fee = await client.observer.getWriteFee();
console.log(`Write fee: ${fee} wei`);
```

***

### getReadFee

Returns the current fee (in wei) required to submit a read request.

| Method       | Type                    |
| ------------ | ----------------------- |
| `getReadFee` | `() => Promise<bigint>` |

```typescript Example theme={null}
const fee = await client.observer.getReadFee();
console.log(`Read fee: ${fee} wei`);
```

***

### getMaxEncryptedDataSize

Returns the maximum encrypted payload size (in bytes) supported by the on-chain
vault path. The CDR contract treats this as a constant, so it is cached for the
lifetime of the Observer.

| Method                    | Type                    |
| ------------------------- | ----------------------- |
| `getMaxEncryptedDataSize` | `() => Promise<bigint>` |

```typescript Example theme={null}
const maxSize = await client.observer.getMaxEncryptedDataSize();
console.log(`Max encrypted payload size: ${maxSize} bytes`);
```

***

### getOperationalThreshold

Returns the DKG operational threshold as a basis-points constant read from the
DKG contract (e.g., `667` = 66.7%).

| Method                    | Type                    |
| ------------------------- | ----------------------- |
| `getOperationalThreshold` | `() => Promise<bigint>` |

```typescript Example theme={null}
const threshold = await client.observer.getOperationalThreshold();
console.log(`Threshold: ${Number(threshold) / 10}%`); // e.g. "66.7%"
```

***

### getActiveRound

Returns the currently active DKG round number. Always hits the DATA Foundation API REST
endpoint, since the active round can transition at any time, so it is never served
from cache.

| Method           | Type                    |
| ---------------- | ----------------------- |
| `getActiveRound` | `() => Promise<number>` |

```typescript Example theme={null}
const round = await client.observer.getActiveRound();
console.log(`Active DKG round: ${round}`);
```

***

### getGlobalPubKey

Returns the DKG global public key from the active round, used for TDH2
encryption. This is an Ed25519 point with a 2-byte curve-code prefix (`0x043f`),
34 bytes total, so it can be passed directly to the WASM TDH2 functions.

| Method            | Type                        |
| ----------------- | --------------------------- |
| `getGlobalPubKey` | `() => Promise<Uint8Array>` |

```typescript Example theme={null}
const globalPubKey = await client.observer.getGlobalPubKey();
console.log(globalPubKey.length); // 34
```

***

### getParticipantCount

Returns the number of validators selected to participate in the active DKG round.

| Method                | Type                    |
| --------------------- | ----------------------- |
| `getParticipantCount` | `() => Promise<number>` |

```typescript Example theme={null}
const count = await client.observer.getParticipantCount();
console.log(`Participating validators: ${count}`);
```

***

### getThreshold

Returns the absolute threshold for the currently active DKG round: the minimum
number of partial decryptions needed to combine. If `minThresholdRatio` is set
on the client, the effective value is
`max(network.threshold, ceil(participants * minThresholdRatio))`.

| Method         | Type                    |
| -------------- | ----------------------- |
| `getThreshold` | `() => Promise<number>` |

```typescript Example theme={null}
const threshold = await client.observer.getThreshold();
console.log(`Need ${threshold} partials to decrypt`);
```

<Note>
  Use this for UI / status display. Do **not** use it to validate a specific
  partial-decryption bucket from `collectPartials`, since a bucket carries its own
  round, which can differ from the active round during DKG rollover. Use
  `getThresholdAt` for that.
</Note>

***

### getThresholdAt

Returns the absolute threshold for a specific DKG round, computed against that
round's own participant total. Used internally by `collectPartials` so a DKG
rollover mid-poll does not measure a bucket against the wrong round.

| Method           | Type                                 |
| ---------------- | ------------------------------------ |
| `getThresholdAt` | `(round: number) => Promise<number>` |

Parameters:

* `round`: The DKG round number to compute the threshold for

```typescript Example theme={null}
const threshold = await client.observer.getThresholdAt(4);
console.log(`Round 4 threshold: ${threshold}`);
```

***

### getRegisteredValidators

Returns a map of validator address → `commPubKey` bytes for the given DKG round
(defaults to the active round). Only includes validators with `Finalized`
status. The `commPubKey` is the secp256k1 public key the validator's TEE uses to
sign partial decryption responses.

| Method                    | Type                                                                |
| ------------------------- | ------------------------------------------------------------------- |
| `getRegisteredValidators` | `(params?: { round?: number }) => Promise<Map<string, Uint8Array>>` |

Parameters:

* `params.round` *(optional)*: DKG round number. Defaults to the active round.

```typescript Example theme={null}
const validators = await client.observer.getRegisteredValidators();
for (const [address, commPubKey] of validators) {
  console.log(address, commPubKey.length);
}
```

***

### getValidatorAttestations

Returns a map of validator address → `enclaveReport` (raw SGX quote bytes) for
the given DKG round (defaults to the active round). Only includes validators
with `Finalized` status. Shares a per-round cache with `getRegisteredValidators`.

| Method                     | Type                                                                |
| -------------------------- | ------------------------------------------------------------------- |
| `getValidatorAttestations` | `(params?: { round?: number }) => Promise<Map<string, Uint8Array>>` |

Parameters:

* `params.round` *(optional)*: DKG round number. Defaults to the active round.

```typescript Example theme={null}
const attestations = await client.observer.getValidatorAttestations();
for (const [address, enclaveReport] of attestations) {
  console.log(address, enclaveReport.length);
}
```

<Note>
  Use with `verifyAttestation()` to verify each validator's TEE enclave before
  trusting their partial decryptions.
</Note>