Make $OPG permits more explicit

Makefile

@@ -31,7 +31,7 @@ docs:
 # Testing
 # ============================================================================
 
-test: utils_test client_test langchain_adapter_test
+test: utils_test client_test langchain_adapter_test opg_token_test
 
 utils_test:
 	pytest tests/utils_test.py -v
@@ -42,6 +42,9 @@ client_test:
 langchain_adapter_test:
 	pytest tests/langchain_adapter_test.py -v
 
+opg_token_test:
+	pytest tests/opg_token_test.py -v
+
 integrationtest:
 	python integrationtest/agent/test_agent.py
 	python integrationtest/workflow_models/test_workflow_models.py
@@ -89,5 +92,5 @@ chat-tool:
 		--max-tokens 100 \
 		--stream
 
-.PHONY: install build publish check docs test utils_test client_test integrationtest examples \
+.PHONY: install build publish check docs test utils_test client_test langchain_adapter_test opg_token_test integrationtest examples \
 	infer completion chat chat-stream chat-tool

README.md

@@ -291,6 +291,18 @@ result = client.llm.chat(
 )
 ```
 
+### OPG Token Approval
+
+LLM inference payments use OPG tokens via the [Permit2](https://github.com/Uniswap/permit2) protocol. Before making requests, ensure your wallet has approved sufficient OPG for spending:
+
+```python
+# Checks current Permit2 allowance — only sends an on-chain transaction
+# if the allowance is below the requested amount.
+client.llm.ensure_opg_approval(opg_amount=5)
+```
+
+This is idempotent: if your wallet already has an allowance >= the requested amount, no transaction is sent.
+
 ## Examples
 
 Additional code examples are available in the [examples](./examples) directory.

docs/opengradient/client/client.md

@@ -15,22 +15,33 @@ Main Client class that unifies all OpenGradient service namespaces.
 Main OpenGradient SDK client.
 
 Provides unified access to all OpenGradient services including LLM inference,
-on-chain model inference, and the Model Hub. Handles authentication via
-blockchain private key and optional Model Hub credentials.
+on-chain model inference, and the Model Hub.
+
+The client operates across two chains:
+
+- **LLM inference** (``client.llm``) settles via x402 on **Base Sepolia**
+  using OPG tokens (funded by ``private_key``).
+- **Alpha Testnet** (``client.alpha``) runs on the **OpenGradient network**
+  using testnet gas tokens (funded by ``alpha_private_key``, or ``private_key``
+  when not provided).
 
 #### Constructor
 
 ```python
-def __init__(private_key: str, email: Optional[str] = None, password: Optional[str] = None, twins_api_key: Optional[str] = None, wallet_address: str = None, rpc_url: str = 'https://ogevmdevnet.opengradient.ai', api_url: str = 'https://sdk-devnet.opengradient.ai', contract_address: str = '0x8383C9bD7462F12Eb996DD02F78234C0421A6FaE', og_llm_server_url: Optional[str] = 'https://llm.opengradient.ai', og_llm_streaming_server_url: Optional[str] = 'https://llm.opengradient.ai')
+def __init__(private_key: str, alpha_private_key: Optional[str] = None, email: Optional[str] = None, password: Optional[str] = None, twins_api_key: Optional[str] = None, wallet_address: str = None, rpc_url: str = 'https://ogevmdevnet.opengradient.ai', api_url: str = 'https://sdk-devnet.opengradient.ai', contract_address: str = '0x8383C9bD7462F12Eb996DD02F78234C0421A6FaE', og_llm_server_url: Optional[str] = 'https://llm.opengradient.ai', og_llm_streaming_server_url: Optional[str] = 'https://llm.opengradient.ai')
 ```
 
 **Arguments**
 
-* **`private_key`**: Private key for OpenGradient transactions.
+* **`private_key`**: Private key whose wallet holds **Base Sepolia OPG tokens**
+        for x402 LLM payments.
+* **`alpha_private_key`**: Private key whose wallet holds **OpenGradient testnet
+        gas tokens** for on-chain inference. Optional -- falls back to
+        ``private_key`` for backward compatibility.
 * **`email`**: Email for Model Hub authentication. Optional.
 * **`password`**: Password for Model Hub authentication. Optional.
 * **`twins_api_key`**: API key for digital twins chat (twin.fun). Optional.
-* **`rpc_url`**: RPC URL for the blockchain network.
+* **`rpc_url`**: RPC URL for the OpenGradient Alpha Testnet.
 * **`api_url`**: API URL for the OpenGradient API.
 * **`contract_address`**: Inference contract address.
 * **`og_llm_server_url`**: OpenGradient LLM server URL.

docs/opengradient/client/index.md

@@ -12,18 +12,29 @@ OpenGradient Client -- the central entry point to all SDK services.
 
 The [Client](./client) class provides unified access to four service namespaces:
 
-- **[llm](./llm)** -- LLM chat and text completion with TEE-verified execution and x402 payment settlement
+- **[llm](./llm)** -- LLM chat and text completion with TEE-verified execution and x402 payment settlement (Base Sepolia OPG tokens)
 - **[model_hub](./model_hub)** -- Model repository management: create, version, and upload ML models
-- **[alpha](./alpha)** -- Alpha Testnet features: on-chain ONNX model inference (VANILLA, TEE, ZKML modes), workflow deployment, and scheduled ML model execution
+- **[alpha](./alpha)** -- Alpha Testnet features: on-chain ONNX model inference (VANILLA, TEE, ZKML modes), workflow deployment, and scheduled ML model execution (OpenGradient testnet gas tokens)
 - **[twins](./twins)** -- Digital twins chat via OpenGradient verifiable inference
 
+## Private Keys
+
+The SDK operates across two chains:
+
+- **`private_key`** -- used for LLM inference (``client.llm``). Pays via x402 on **Base Sepolia** with OPG tokens.
+- **`alpha_private_key`** *(optional)* -- used for Alpha Testnet features (``client.alpha``). Pays gas on the **OpenGradient network** with testnet tokens. Falls back to ``private_key`` when omitted.
+
 ## Usage
 
 ```python
 import opengradient as og
 
+# Single key for both chains (backward compatible)
 client = og.init(private_key="0x...")
 
+# Separate keys: Base Sepolia OPG for LLM, OpenGradient testnet gas for Alpha
+client = og.init(private_key="0xLLM_KEY...", alpha_private_key="0xALPHA_KEY...")
+
 # LLM chat (TEE-verified, streamed)
 for chunk in client.llm.chat(
     model=og.TEE_LLM.CLAUDE_3_5_HAIKU,
@@ -53,6 +64,7 @@ repo = client.model_hub.create_model("my-model", "A price prediction model")
 * [exceptions](./exceptions): Exception types for OpenGradient SDK errors.
 * [llm](./llm): LLM chat and completion via TEE-verified execution with x402 payments.
 * [model_hub](./model_hub): Model Hub for creating, versioning, and uploading ML models.
+* [opg_token](./opg_token): OPG token Permit2 approval utilities for x402 payments.
 * [twins](./twins): Digital twins chat via OpenGradient verifiable inference.
 
 ## Classes
@@ -62,22 +74,33 @@ repo = client.model_hub.create_model("my-model", "A price prediction model")
 Main OpenGradient SDK client.
 
 Provides unified access to all OpenGradient services including LLM inference,
-on-chain model inference, and the Model Hub. Handles authentication via
-blockchain private key and optional Model Hub credentials.
+on-chain model inference, and the Model Hub.
+
+The client operates across two chains:
+
+- **LLM inference** (``client.llm``) settles via x402 on **Base Sepolia**
+  using OPG tokens (funded by ``private_key``).
+- **Alpha Testnet** (``client.alpha``) runs on the **OpenGradient network**
+  using testnet gas tokens (funded by ``alpha_private_key``, or ``private_key``
+  when not provided).
 
 #### Constructor
 
 ```python
-def __init__(private_key: str, email: Optional[str] = None, password: Optional[str] = None, twins_api_key: Optional[str] = None, wallet_address: str = None, rpc_url: str = 'https://ogevmdevnet.opengradient.ai', api_url: str = 'https://sdk-devnet.opengradient.ai', contract_address: str = '0x8383C9bD7462F12Eb996DD02F78234C0421A6FaE', og_llm_server_url: Optional[str] = 'https://llm.opengradient.ai', og_llm_streaming_server_url: Optional[str] = 'https://llm.opengradient.ai')
+def __init__(private_key: str, alpha_private_key: Optional[str] = None, email: Optional[str] = None, password: Optional[str] = None, twins_api_key: Optional[str] = None, wallet_address: str = None, rpc_url: str = 'https://ogevmdevnet.opengradient.ai', api_url: str = 'https://sdk-devnet.opengradient.ai', contract_address: str = '0x8383C9bD7462F12Eb996DD02F78234C0421A6FaE', og_llm_server_url: Optional[str] = 'https://llm.opengradient.ai', og_llm_streaming_server_url: Optional[str] = 'https://llm.opengradient.ai')
 ```
 
 **Arguments**
 
-* **`private_key`**: Private key for OpenGradient transactions.
+* **`private_key`**: Private key whose wallet holds **Base Sepolia OPG tokens**
+        for x402 LLM payments.
+* **`alpha_private_key`**: Private key whose wallet holds **OpenGradient testnet
+        gas tokens** for on-chain inference. Optional -- falls back to
+        ``private_key`` for backward compatibility.
 * **`email`**: Email for Model Hub authentication. Optional.
 * **`password`**: Password for Model Hub authentication. Optional.
 * **`twins_api_key`**: API key for digital twins chat (twin.fun). Optional.
-* **`rpc_url`**: RPC URL for the blockchain network.
+* **`rpc_url`**: RPC URL for the OpenGradient Alpha Testnet.
 * **`api_url`**: API URL for the OpenGradient API.
 * **`contract_address`**: Inference contract address.
 * **`og_llm_server_url`**: OpenGradient LLM server URL.

docs/opengradient/client/llm.md

@@ -18,6 +18,11 @@ Provides access to large language model completions and chat via TEE
 (Trusted Execution Environment) with x402 payment protocol support.
 Supports both streaming and non-streaming responses.
 
+Before making LLM requests, ensure your wallet has approved sufficient
+OPG tokens for Permit2 spending by calling ``ensure_opg_approval``.
+This only sends an on-chain transaction when the current allowance is
+below the requested amount.
+
 #### Constructor
 
 ```python
@@ -31,7 +36,7 @@ def __init__(wallet_account: `LocalAccount`, og_llm_server_url: str, og_llm_st
 #### `chat()`
 
 ```python
-def chat(self, model: `TEE_LLM`, messages: List[Dict], max_tokens: int = 100, stop_sequence: Optional[List[str]] = None, temperature: float = 0.0, tools: Optional[List[Dict]] = [], tool_choice: Optional[str] = None, x402_settlement_mode: Optional[`x402SettlementMode`] = x402SettlementMode.SETTLE_BATCH, stream: bool = False) ‑> Union[`TextGenerationOutput`, `TextGenerationStream`]
+def chat(self, model: `TEE_LLM`, messages: List[Dict], max_tokens: int = 100, stop_sequence: Optional[List[str]] = None, temperature: float = 0.0, tools: Optional[List[Dict]] = None, tool_choice: Optional[str] = None, x402_settlement_mode: Optional[`x402SettlementMode`] = x402SettlementMode.SETTLE_BATCH, stream: bool = False) ‑> Union[`TextGenerationOutput`, `TextGenerationStream`]
 ```
 Perform inference on an LLM model using chat via TEE.
 
@@ -92,4 +97,32 @@ TextGenerationOutput: Generated text results including:
 
 **Raises**
 
-* **`OpenGradientError`**: If the inference fails.
+* **`OpenGradientError`**: If the inference fails.
+
+---
+
+#### `ensure_opg_approval()`
+
+```python
+def ensure_opg_approval(self, opg_amount: float) ‑> `Permit2ApprovalResult`
+```
+Ensure the Permit2 allowance for OPG is at least ``opg_amount``.
+
+Checks the current Permit2 allowance for the wallet. If the allowance
+is already >= the requested amount, returns immediately without sending
+a transaction. Otherwise, sends an ERC-20 approve transaction.
+
+**Arguments**
+
+* **`opg_amount`**: Minimum number of OPG tokens required (e.g. ``5.0``
+        for 5 OPG). Converted to base units (18 decimals) internally.
+
+**Returns**
+
+Permit2ApprovalResult: Contains ``allowance_before``,
+    ``allowance_after``, and ``tx_hash`` (None when no approval
+    was needed).
+
+**Raises**
+
+* **`OpenGradientError`**: If the approval transaction fails.

docs/opengradient/client/opg_token.md

@@ -0,0 +1,64 @@
+---
+outline: [2,3]
+---
+
+[opengradient](../index) / [client](./index) / opg_token
+
+# Package opengradient.client.opg_token
+
+OPG token Permit2 approval utilities for x402 payments.
+
+## Functions
+
+---
+
+### `ensure_opg_approval()`
+
+```python
+def ensure_opg_approval(wallet_account: `LocalAccount`, opg_amount: float) ‑> `Permit2ApprovalResult`
+```
+Ensure the Permit2 allowance for OPG is at least ``opg_amount``.
+
+Checks the current Permit2 allowance for the wallet. If the allowance
+is already >= the requested amount, returns immediately without sending
+a transaction. Otherwise, sends an ERC-20 approve transaction.
+
+**Arguments**
+
+* **`wallet_account`**: The wallet account to check and approve from.
+* **`opg_amount`**: Minimum number of OPG tokens required (e.g. ``5.0``
+        for 5 OPG). Converted to base units (18 decimals) internally.
+
+**Returns**
+
+Permit2ApprovalResult: Contains ``allowance_before``,
+    ``allowance_after``, and ``tx_hash`` (None when no approval
+    was needed).
+
+**Raises**
+
+* **`OpenGradientError`**: If the approval transaction fails.
+
+## Classes
+
+### `Permit2ApprovalResult`
+
+Result of a Permit2 allowance check / approval.
+
+**Attributes**
+
+* **`allowance_before`**: The Permit2 allowance before the method ran.
+* **`allowance_after`**: The Permit2 allowance after the method ran.
+* **`tx_hash`**: Transaction hash of the approval, or None if no transaction was needed.
+
+#### Constructor
+
+```python
+def __init__(allowance_before: int, allowance_after: int, tx_hash: Optional[str] = None)
+```
+
+#### Variables
+
+* static `allowance_after` : int
+* static `allowance_before` : int
+* static `tx_hash` : Optional[str]

docs/opengradient/index.md

@@ -6,7 +6,7 @@ opengradient
 
 # Package opengradient
 
-**Version: 0.7.0**
+**Version: 0.7.1**
 
 OpenGradient Python SDK for decentralized AI inference with end-to-end verification.
 
@@ -55,12 +55,24 @@ result = client.alpha.infer(
 print(result.model_output)
 ```
 
+## Private Keys
+
+The SDK operates across two chains. You can use a single key for both, or provide separate keys:
+
+- **``private_key``** -- pays for LLM inference via x402 on **Base Sepolia** (requires OPG tokens)
+- **``alpha_private_key``** *(optional)* -- pays gas for Alpha Testnet on-chain inference on the **OpenGradient network** (requires testnet gas tokens). Falls back to ``private_key`` when omitted.
+
+```python
+# Separate keys for each chain
+client = og.init(private_key="0xBASE_KEY...", alpha_private_key="0xALPHA_KEY...")
+```
+
 ## Client Namespaces
 
 The [Client](./client/index) object exposes four namespaces:
 
-- **[llm](./client/llm)** -- Verifiable LLM chat and completion via TEE-verified execution with x402 payments
-- **[alpha](./client/alpha)** -- On-chain ONNX model inference, workflow deployment, and scheduled ML model execution (only available on the Alpha Testnet)
+- **[llm](./client/llm)** -- Verifiable LLM chat and completion via TEE-verified execution with x402 payments (Base Sepolia OPG tokens)
+- **[alpha](./client/alpha)** -- On-chain ONNX model inference, workflow deployment, and scheduled ML model execution (OpenGradient testnet gas tokens)
 - **[model_hub](./client/model_hub)** -- Model repository management
 - **[twins](./client/twins)** -- Digital twins chat via OpenGradient verifiable inference (requires twins API key)
 
@@ -96,7 +108,7 @@ The SDK includes adapters for popular AI frameworks -- see the `agents` submodul
 ### `init()`
 
 ```python
-def init(private_key: str, email: Optional[str] = None, password: Optional[str] = None, **kwargs) ‑> `Client`
+def init(private_key: str, alpha_private_key: Optional[str] = None, email: Optional[str] = None, password: Optional[str] = None, **kwargs) ‑> `Client`
 ```
 Initialize the global OpenGradient client.
 
@@ -105,7 +117,11 @@ and stores it as the global client for convenience.
 
 **Arguments**
 
-* **`private_key`**: Private key for OpenGradient transactions.
+* **`private_key`**: Private key whose wallet holds **Base Sepolia OPG tokens**
+        for x402 LLM payments.
+* **`alpha_private_key`**: Private key whose wallet holds **OpenGradient testnet
+        gas tokens** for on-chain inference. Optional -- falls back to
+        ``private_key`` for backward compatibility.
 * **`email`**: Email for Model Hub authentication. Optional.
 * **`password`**: Password for Model Hub authentication. Optional.
     **kwargs: Additional arguments forwarded to `Client`.
@@ -121,22 +137,33 @@ The newly created `Client` instance.
 Main OpenGradient SDK client.
 
 Provides unified access to all OpenGradient services including LLM inference,
-on-chain model inference, and the Model Hub. Handles authentication via
-blockchain private key and optional Model Hub credentials.
+on-chain model inference, and the Model Hub.
+
+The client operates across two chains:
+
+- **LLM inference** (``client.llm``) settles via x402 on **Base Sepolia**
+  using OPG tokens (funded by ``private_key``).
+- **Alpha Testnet** (``client.alpha``) runs on the **OpenGradient network**
+  using testnet gas tokens (funded by ``alpha_private_key``, or ``private_key``
+  when not provided).
 
 #### Constructor
 
 ```python
-def __init__(private_key: str, email: Optional[str] = None, password: Optional[str] = None, twins_api_key: Optional[str] = None, wallet_address: str = None, rpc_url: str = 'https://ogevmdevnet.opengradient.ai', api_url: str = 'https://sdk-devnet.opengradient.ai', contract_address: str = '0x8383C9bD7462F12Eb996DD02F78234C0421A6FaE', og_llm_server_url: Optional[str] = 'https://llm.opengradient.ai', og_llm_streaming_server_url: Optional[str] = 'https://llm.opengradient.ai')
+def __init__(private_key: str, alpha_private_key: Optional[str] = None, email: Optional[str] = None, password: Optional[str] = None, twins_api_key: Optional[str] = None, wallet_address: str = None, rpc_url: str = 'https://ogevmdevnet.opengradient.ai', api_url: str = 'https://sdk-devnet.opengradient.ai', contract_address: str = '0x8383C9bD7462F12Eb996DD02F78234C0421A6FaE', og_llm_server_url: Optional[str] = 'https://llm.opengradient.ai', og_llm_streaming_server_url: Optional[str] = 'https://llm.opengradient.ai')
 ```
 
 **Arguments**
 
-* **`private_key`**: Private key for OpenGradient transactions.
+* **`private_key`**: Private key whose wallet holds **Base Sepolia OPG tokens**
+        for x402 LLM payments.
+* **`alpha_private_key`**: Private key whose wallet holds **OpenGradient testnet
+        gas tokens** for on-chain inference. Optional -- falls back to
+        ``private_key`` for backward compatibility.
 * **`email`**: Email for Model Hub authentication. Optional.
 * **`password`**: Password for Model Hub authentication. Optional.
 * **`twins_api_key`**: API key for digital twins chat (twin.fun). Optional.
-* **`rpc_url`**: RPC URL for the blockchain network.
+* **`rpc_url`**: RPC URL for the OpenGradient Alpha Testnet.
 * **`api_url`**: API URL for the OpenGradient API.
 * **`contract_address`**: Inference contract address.
 * **`og_llm_server_url`**: OpenGradient LLM server URL.