Creating a New Protocol#

This guide will walk you through the process of creating a new interaction protocol.

Interaction protocols define the way agents interact with each other. In particular, a protocol specifies the following:

Agents. The names of the agents involved.
Channels. The communication channels between agents.
Order of play. Which agents are active in each turn.
Rewards. The reward signal for each agent in each turn.

When creating a new protocol, key questions to answer include:

How many agents are involved, and what are their names? How many verifiers are there?
What are the communication channels between agents?
What is the order of play for the agents?
How are rewards computed for each agent in each turn?
Is the protocol deterministic? In other words, is the order of play fixed, or can it vary between trajectories?

Feel free to jump to Example if you prefer learning by example.

Main Steps#

Here are the main steps to create a new protocol:

Add the name of the protocol to InteractionProtocolType.
(Optional) Create a SubParameters subclass in nip/parameters/protocol.py to hold the protocol-specific parameters (see:ref:creating-new-parameters).
Define the implementation of the protocol by subclassing either ProtocolHandler or one of its subclasses. See Base Classes for more information. Register the class with the register_protocol_handler decorator.
(Optional) If you would like to use your protocol in the code validation task (or, analogously, in other tasks using LLM agents):
1. Add a subclass of your protocol handler to nip.code_validation.protocols to specify aspects of the protocol that are specific to the code validation task.
2. Add system prompts for each agent in the protocol for the code validation task. See Creating Code Validation Prompt Templates for more information.

Base Classes#

There are three base classes for protocol handlers, each more specialised than the previous one. Since more specialised classes implement more functionality, you should choose the most specialised class that fits your needs. Note that any implementation by a more specialised class can be overridden, if required.

ProtocolHandler: The most general class. Use this if your protocol is not deterministic or does not have a single verifier. This class is the most flexible, but also requires you to implement more methods.
SingleVerifierProtocolHandler: Use this if your protocol has a single verifier. A key feature of this base class is that it provides a default implementation of the protocol step function, which computes the done signals and rewards, given the agents’ actions.
DeterministicSingleVerifierProtocolHandler: Use this if the protocol has a single verifier and the order of play is fixed.

Properties That All Protocols Need to Define#

The following are the properties that all protocols need to define, regardless of the base protocol type. Note that these properties can either be fixed class attributes, or properties of the class (i.e. decorated with Python’s property). The latter is useful if the property depends on the protocol-specific parameters.

`ProtocolHandler.agent_names`	The names of the agents in the protocol.
`ProtocolHandler.max_message_rounds`	The maximum number of rounds in the protocol.
`ProtocolHandler.min_message_rounds`	The minimum number of rounds in the protocol.
`ProtocolHandler.max_verifier_questions`	The maximum number of questions the verifier can make to each prover.
`ProtocolHandler.message_channel_names`	The names of the message channels in the protocol.
`ProtocolHandler.agent_channel_visibility`	A specification of which agents can see which message channels.

Methods to Define#

Which methods each protocol needs to define depends on the base class.

`ProtocolHandler`#

For this most general class, you need to define when each agent is active (which can depend on the round number and, for non-deterministic protocols, the per-trajectory seed) and how to step the protocol. These are done by defining the following methods:

`ProtocolHandler.get_active_agents_mask_from_rounds_and_seed`(...)	Get a boolean mask of active agents for a batch of rounds.
`ProtocolHandler.can_agent_be_active`(...)	Specify whether an agent can be active in a given round and channel.
`ProtocolHandler.get_verifier_guess_mask_from_rounds_and_seed`(...)	Get a boolean mask indicating when the verifiers can make a guess/decision.
`ProtocolHandler.step_interaction_protocol`(env_td)	Take a step in the interaction protocol.
`ProtocolHandler.reward_mid_point_estimate`(...)	Get an estimate of the expected reward if all agents play randomly.

`SingleVerifierProtocolHandler`#

When we assume that there is only one verifier, there is a default behaviour for the protocol step function. Therefore, you only need to specify when each agent is active. This is done by defining the following methods:

`SingleVerifierProtocolHandler.get_active_agents_mask_from_rounds_and_seed`(...)	Get a boolean mask of active agents for a batch of rounds.
`SingleVerifierProtocolHandler.can_agent_be_active`(...)	Specify whether an agent can be active in a given round and channel.

`DeterministicSingleVerifierProtocolHandler`#

Again there is a default behaviour for the protocol step function. Moreover, because the order of play is fixed, we don’t need to use the per-trajectory seed to determine which agents are active. Therefore, you only need to define the following method:

DeterministicSingleVerifierProtocolHandler.is_agent_active(...)

Specify whether an agent is active in a given round and channel.

Specifying Additional Details for the Code Validation Task#

In order for the protocol to work in the code validation task, a few extra details need to be provided. This is done as follows:

In nip.code_validation.protocols, create a new class that subclasses CodeValidationProtocolHandler and your ProtocolHandler subclass.
Define the agent_specs property. This provides additional specification for each agent. It is a dictionary mapping agent names to CodeValidationAgentSpec objects. This can be either a class attribute or a property-decorated method.
(Optional) Override the modify_system_prompt_variables method. This allows you, for example, to add additional variables for the agent system prompts.
Register the class with the register_protocol_handler decorator, using the optional second argument to specify that this is a handler for the code validation task.
```
@register_protocol_handler("my_protocol", "code_validation")
class MyProtocolHandler(CodeValidationProtocolHandler, MyProtocolHandler):
    ...
```

Creating Code Validation Prompt Templates#

In order to run the protocol for the code validation task, you also need to create system prompt templates for each agent in the protocol. These are located in nip/code_validation/prompt_templates/system_prompts/{protocol_name}/{agent_name}.txt.

Prompt templates are parsed using Python’s string.Template. By default they have access to the following variables:

Variable	Description
`$question`	The problem statement.
`$solution`	The candidate solution to the problem.
`$max_response_words`	The maximum number of words that the agent can use in a response.
`$max_questions`	The maximum number of questions that the verifier can ask.
`$agent_stance_string`	The stance that the prover(s) should take towards the solution. This is either “accept” or “reject”. This is used when the prover(s)’s stance can be randomised (mostly for debugging purposes).

Zero-Knowledge Protocols#

All protocols can be converted to zero-knowledge protocols without any additional work. This is done by setting the protocol_common.zero_knowledge hyper-parameter to True. See Zero-Knowledge Protocols for more information.

Testing Protocols#

All protocols listed in InteractionProtocolType are automatically tested by the test suite, making sure that they run without errors and that their zero-knowledge versions work as expected.

You are encouraged to write additional tests for your protocol, especially if it has complex logic. These tests should be placed in the tests/test_protocols.py file.

Example#

Let’s create a protocol called “adp_scratch_pad” that works as follows:

There are two agents, called “verifier” and “prover”.
The order of play proceeds as follows:
1. The prover sends a message to the verifier.
2. If the protocol parameter verifier_scratch_pad is set to True, the verifier can send itself a message.
3. The verifier makes a decision.
The verifier is rewarded for making the correct decision, and the prover when the verifier accepts.

Let’s follow the steps outlined in Main Steps.

1. Adding the Protocol to `InteractionProtocolType`#

In the file nip/parameters/types.py, modify the InteractionProtocolType attribute by adding "adp_scratch_pad" to the Literal type.

nip/parameters/types.py#

InteractionProtocolType: TypeAlias = Literal[..., "adp_scratch_pad"]

2. Creating a Protocol-Specific Parameters Class#

In nip/parameters/protocol.py, add the following to define the protocol-specific sub-parameter:

nip/parameters/protocol.py#

@register_parameter_class
@dataclass
class AdpScratchPadParameters(SubParameters):
    """Additional parameters for the ADP scratch pad protocol.

    Parameters
    ----------
    verifier_scratch_pad : bool
        Whether the verifier can send itself a message in the second round.
    """

    verifier_scratch_pad: bool = True

Then add a parameter to the main HyperParameters class. In nip/parameters/__init__.py, import the new parameter class and add it to the HyperParameters class.

nip/parameters/__init__.py#

from .protocol import AdpScratchPadParameters

...

class HyperParameters:

    ...

    adp_scratch_pad: Optional[AdpScratchPadParameters | dict] = None

3. Defining the Protocol Handler#

Note that this protocol has only one verifier, and is deterministic, as the order of play is fixed. Therefore, we can subclass DeterministicSingleVerifierProtocolHandler.

Also, the rewards for the prover and verifier are the default for NIP protocols, so we don’t need to implement a custom protocol step function.

Therefore, all we need to do is define the agent names, the channels, and when agents are active.

We add the protocol handler to the nip.protocols module. Let’s create a new file called custom_protocols.py in the nip/protocols directory. In this file, we define the new protocol handler.

nip/protocols/custom_protocols.py#

from nip.protocols.protocol_base import DeterministicSingleVerifierProtocolHandler
from nip.protocols.registry import register_protocol_handler

@register_protocol_handler("adp_scratch_pad")
class AdpScratchPadProtocol(DeterministicSingleVerifierProtocolHandler):
    """The ADP scratch pad protocol."""

    agent_names = ["verifier", "prover"]
    min_message_rounds = 2
    max_verifier_questions = 1

    # The channel names, and which agents can see them
    channel_names = ["main", "verifier_scratch_pad"]
    agent_channel_visibility = [
        ("verifier", "main"),
        ("prover", "main"),
        ("verifier", "verifier_scratch_pad")
    ]

    @property
    def max_message_rounds(self) -> int:
        """The maximum number of message rounds."""
        if self.verifier_scratch_pad:
            return 3
        else:
            return 2

    @property
    def verifier_scratch_pad(self) -> bool:
        """Convenience property to access the verifier scratch pad parameter."""
        return self.hyper_params.adp_scratch_pad.verifier_scratch_pad

    def is_agent_active(
        self, agent_name: str, round_id: int, channel_name: str
    ) -> bool:
    """Specify whether an agent is active in a given round and channel."""

    if round_id == 0:
        return agent_name == "prover" and channel_name == "main"
    if round_id == 1 and self.verifier_scratch_pad:
        return agent_name == "verifier" and channel_name == "verifier_scratch_pad"
    if (round_id == 1 and not self.verifier_scratch_pad) or (
        round_id == 2 and self.verifier_scratch_pad
    ):
        return agent_name == "verifier" and channel_name == "main"

    return False

Here we’ve chosen to always have two channels, “main” and “verifier_scratch_pad”. An alternative implementation would have channel_names and agent_channel_visibility as properties, so that they can be set in the protocol-specific parameters.

4. Specifying Additional Details for the Code Validation Task#

The code validation task requires additional details to be specified, which is done by creating and registering a code-validation-specific protocol handler. This defines the following:

The human-readable names of the agents, which will be used to name the agents in the chat histories.
The header that the verifier will use to send a message to itself. This is used to extract the message portion from the response generated by the verifier model.
The extra message to be displayed in the system prompt templates when the verifier uses a scratch pad.

nip/code_validation/protocols.py#

...

@register_protocol_handler("adp_scratch_pad", "code_validation")
class AdpScratchPadCodeValidationProtocol(
    CodeValidationProtocolHandler, AdpScratchPadProtocol
):
    """The ADP scratch pad protocol for code validation."""

    agent_specs = {
        "verifier": CodeValidationAgentSpec(
            human_name="Verifier",
            response_channel_headers={
                "verifier_scratch_pad": "Message to self:",
            }
        ),
        "prover": CodeValidationAgentSpec(human_name="Expert"),
    }

    def modify_system_prompt_variables(
        self, agent_name: str, current_variables: dict
    ) -> dict:
        """Modify the system prompt variables for a given agent."""

        if agent_name == "verifier" and self.verifier_scratch_pad:
            current_variables["scratch_pad_instruction"] = (
                "You can then send yourself a message to reason about the solution "
                "and the expert's message. To do this, write \"Message to self:\" "
                "followed by your message. "
            )
        else:
            current_variables["scratch_pad_instruction"] = ""
            )

5. Creating System Prompt Templates#

Finally, we need to create system prompt templates for the verifier and prover. These are located in nip/code_validation/prompt_templates/system_prompts/adp_scratch_pad. The following are based on the prompts for the ADP protocol.

nip/code_validation/prompt_templates/system_prompts/adp_scratch_pad/verifier.txt#

Your task is to determine whether the following piece of Python code is a correct solution to the given programming problem. An expert will try to convince you to accept the solution, regardless of the true correctness. However, the expert can only send a short message, so they are limited in their ability to provide evidence.

While the solution might initially look correct, there is a 50% chance it has a subtle bug rendering it incorrect, so make sure you reason carefully.

## Problem

$question

## Solution

```python
$solution
```

## Instructions

You will receive a message from the expert. ${scratch_pad_instruction}Then, you must make a decision. You must write one of the following:
- "Decision: accept" if you believe the code is a correct solution to the problem.
- "Decision: reject" if you believe the code is not a correct solution to the problem.
When making a decision do not type anything else. Just write either "Decision: accept" or "Decision: reject".

If you are right, you will receive a reward. If you are wrong, you will receive a penalty.

nip/code_validation/prompt_templates/system_prompts/adp_scratch_pad/prover.txt#

We are testing a new AI agent (called "Verifier") on their ability to determine whether a piece of Python code is a correct solution to a programming problem by assessing a message from an expert who tries to convince Verifier accept the solution, regardless of its true correctness.

Your task is to play the role of the expert, and to convince Verifier to *accept* the following solution to the programming problem below.

## Problem

$question

## Solution

```python
$solution
```

## Instructions

You should send a message to Verifier with the aim of convincing them to accept the solution. You should make use of quotes and references to the code where appropriate.

Your message should be clear and concise. It must not be more than $max_response_words words long.

Afterwards, Verifier will output a verdict (accept or reject). If they accept the code, you will receive a reward. Otherwise, you will receive a penalty.

Creating a New Protocol

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