picon-eval 0.1.6

Persona Interview & Consistency Evaluation Framework

PICON — Persona Interrogation framework for Consistency evaluation

---

An official Python package for evaluating LLM-based persona agents, called PICON. By running a multi-turn interview and fact-checking pipeline, you can measure how consistently and accurately a persona agent behaves. PICON evaluates persona agents across three dimensions:

• Internal Consistency: freedom from self-contradiction across answers.
• External Consistency: alignment of claims with real-world facts (via web search).
• Retest Stability: consistency of answers when the same questions are repeated within and across sessions.

 

 

Results

No persona group achieved a larger consistency area than the human baseline, suggesting that current persona agents have not yet reached the level of a real person faithfully embodying their own identity. Inference-time conditioning methods (prompting or RAG) tended to score higher than fine-tuned models, indicating that fine-tuning for persona may not be sufficient for robust consistency under chained interrogation.

 

Installation

pip install picon-eval

import picon
print(picon.__version__)

For development or full extras (CharacterAI, Google GenAI, etc.):

git clone https://github.com/anonymous/picon.git
cd picon
pip install -e ".[all]"

 

Tutorial

For a hands-on walkthrough of PICON's features, see the picon_tutorial.ipynb notebook. It covers installation, running interviews, evaluation, and interpreting results with worked examples.

 

 

Quick Starts

[!NOTE] Before using PICON, you must provide API keys either directly or in a .env file.

• OpenAI models (gpt-*): Set OPENAI_API_KEY in your .env file.
• Gemini models (gemini/*): Set GEMINI_API_KEY in your .env file.
• Web search (external verification): Set SERPER_API_KEY in your .env file. Get one at serper.dev.

 

Environment Variables

Create a .env file in your working directory:

# LLM API Keys (at least one required)
OPENAI_API_KEY="YOUR_OPENAI_KEY"
GEMINI_API_KEY="YOUR_GEMINI_KEY"

# Web Search (required for external verification)
SERPER_API_KEY="YOUR_SERPER_KEY"

# Address validation (required for external verification)
GOOGLE_GEOCODE="YOUR_GOOGLE_GEOCODE_KEY"

# Optional
ANTHROPIC_API_KEY="YOUR_ANTHROPIC_KEY"
GOOGLE_CLAIM_SEARCH="YOUR_GOOGLE_API_KEY"       # Fact-check search
GOOGLE_CX_ID="YOUR_CUSTOM_SEARCH_ENGINE_ID"     # Custom Search Engine ID

# AWS Bedrock (for bedrock/anthropic.claude-* models)
AWS_ACCESS_KEY_ID="YOUR_AWS_ACCESS_KEY"
AWS_SECRET_ACCESS_KEY="YOUR_AWS_SECRET_KEY"
AWS_REGION="us-west-2"

# Google Vertex AI (for vertex_ai/claude-* models)
GOOGLE_APPLICATION_CREDENTIALS="/path/to/service-account.json"

[!TIP] PICON supports Claude via direct Anthropic API (claude-*), AWS Bedrock (bedrock/anthropic.claude-*), and Google Vertex AI (vertex_ai/claude-*). Provider-specific reasoning/thinking parameters are handled automatically.

 

Evaluate an LLM Persona (Simple API)

For quick evaluations, use the picon.run() shortcut:

import picon

result = picon.run(
    model="gpt-5",
    persona="You are a 35-year-old software engineer living in Seoul.",
    name="John",
    num_turns=20,
    num_sessions=2,
    do_eval=True,
)

print(result.eval_scores)
result.save("results/john.json")

# Equivalent CLI command
picon --agent_model gpt-5 \
      --agent_persona "You are a 35-year-old software engineer living in Seoul." \
      --agent_name "John" \
      --num_turns 20 --num_sessions 2 --do_eval

 

Component-Based Usage

Import individual components and compose your own simulation pipeline:

from picon import Questioner, EntityExtractor, Evaluator, Interviewee
from picon import InterrogationSimulation

# Set up agents
questioner = Questioner(model="gpt-5")
extractor = EntityExtractor(model="gpt-5.1")
evaluator = Evaluator(model="gemini/gemini-2.5-flash")

# Set up the persona to evaluate
interviewee = Interviewee(
    model="gpt-5",
    persona="You are a 35-year-old software engineer living in Seoul.",
    name="John",
)

# Run the full interview + evaluation pipeline
sim = InterrogationSimulation(
    interviewee=interviewee,
    questioner=questioner,
    extractor=extractor,
    evaluator=evaluator,
    num_turns=20,
    num_sessions=2,
)
result = sim.run(do_eval=True)

print(result.eval_scores)
result.save("results/john.json")

# Example output:
# {
#     "ic_score": 0.82,
#     "external_ec": 0.75,
#     "inter_session_stability": 0.68,
#     "intra_session_stability": 0.91,
# }

With default agent models, you can omit agent setup entirely:

from picon import Interviewee, InterrogationSimulation

interviewee = Interviewee(model="gpt-5", persona="You are ...", name="John")
result = InterrogationSimulation(interviewee=interviewee, num_turns=20).run()

 

Evaluate an External Agent Endpoint

If you already have a persona agent running (e.g. a wrapping server, fine-tuned model, RAG agent), provide its OpenAI-compatible endpoint URL (/v1/chat/completions).

from picon import Interviewee, InterrogationSimulation

interviewee = Interviewee(api_base="http://localhost:8000/v1", name="MyAgent")
result = InterrogationSimulation(interviewee=interviewee, num_turns=20).run()

# Equivalent CLI command
picon --agent_api_base http://localhost:8000/v1 \
      --agent_name "MyAgent" \
      --num_turns 20 --num_sessions 2 --do_eval

 

Self-hosted Models (vLLM)

For self-hosted models, provide both api_base and model:

from picon import Interviewee, InterrogationSimulation

interviewee = Interviewee(
    api_base="http://localhost:8000/v1",
    model="meta-llama/Llama-3-8B",
    persona="You are a 30-year-old teacher named Jane...",
    name="Jane",
)
result = InterrogationSimulation(interviewee=interviewee).run()

picon --agent_api_base http://localhost:8000/v1 \
      --agent_model meta-llama/Llama-3-8B \
      --agent_persona "You are a 30-year-old teacher named Jane..." \
      --agent_name "Jane" --do_eval

 

Separate Interview and Evaluation

import picon

# Step 1: Interview only
interview_result = picon.run_interview(
    name="John",
    model="gpt-5",
    persona="You are a 35-year-old software engineer...",
    num_turns=50,
    num_sessions=2,
    verbose=True
)

# Step 2: Evaluate
persona_stats = picon.run_evaluation(interview_result, eval_factors=["internal", "external"])
print(persona_stats)

Evaluate an Existing Result File

scores = picon.evaluate("results/john.json", eval_factors=["internal", "external"])

 

 

Connecting an External Agent

PICON can evaluate any persona agent that exposes an OpenAI-compatible chat completions endpoint (POST /v1/chat/completions). If your agent already serves this endpoint (e.g. vLLM or any OpenAI-compatible server), just pass the URL directly — no wrapping needed.

 

Case 1: Your agent already has an OpenAI-compatible endpoint

If you're serving a model via vLLM or any server that implements /v1/chat/completions:

import picon

result = picon.run(
    api_base="http://<your-server-ip>:8000/v1",
    name="Alice",
    do_eval=True,
)

picon --agent_api_base http://<your-server-ip>:8000/v1 \
      --agent_name "Alice" --do_eval

 

Case 2: Your agent has custom logic (RAG, API calls, etc.)

If your agent doesn't have an OpenAI-compatible endpoint, wrap it with a simple server. You only need to implement one endpoint that accepts messages and returns a response:

import time
from fastapi import FastAPI, Request
from fastapi.responses import JSONResponse
import uvicorn

app = FastAPI()

def generate_response(messages: list) -> str:
    """Replace this with your own agent logic."""
    user_message = messages[-1]["content"]
    # ... your custom logic (RAG retrieval, API call, etc.) ...
    return "This is my response."

@app.post("/v1/chat/completions")
async def chat_completions(request: Request):
    body = await request.json()
    messages = body.get("messages", [])

    content = generate_response(messages)

    return {
        "id": f"chatcmpl-{int(time.time())}",
        "object": "chat.completion",
        "created": int(time.time()),
        "model": "my-agent",
        "choices": [{
            "index": 0,
            "message": {"role": "assistant", "content": content},
            "finish_reason": "stop",
        }],
        "usage": {"prompt_tokens": 0, "completion_tokens": 0, "total_tokens": 0},
    }

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8001)

Then evaluate with PICON:

picon --agent_api_base http://<your-server-ip>:8001/v1 \
      --agent_name "MyAgent" --do_eval

See examples/ for full end-to-end scripts with vLLM + LoRA and HumanSimulacra RAG

 

 

Reproducibility

To reproduce full benchmark results, run each agent's script after setting the required API keys in .env:

# 1. Install
pip install -e ".[all]"

# 2. Set API keys
cp .env.example .env
# Edit .env with your keys

# 3. Run each benchmark agent
bash scripts/nemotron.sh
bash scripts/twin_2k_500.sh
bash scripts/llm_generated.sh
bash scripts/deeppersona.sh        # requires: DATASET_DIR=/path/to/deeppersona
bash scripts/human_simulacra.sh   # wrapping server auto-started per character

# OpenCharacter: serve your OpenCharacter-compatible model via vLLM first
vllm serve <your-opencharacter-model> --port 8000
VLLM_BASE=http://localhost:8000/v1 VLLM_MODEL=<your-opencharacter-model> bash scripts/opencharacter.sh

# ConsistentLLM: requires fine-tuned model served via vLLM first
vllm serve anonymous/consistent_llm_llama-8b-sft-ppo-prompt --port 8001
bash scripts/consistent_llm.sh    # SIMULATOR_PORT=8001 by default

# Character.AI (requires CAI_TOKEN in .env):
bash scripts/characterai.sh

All scripts write results to data/results/ and evaluation scores to data/evaluation/. By default, each script randomly samples 10 personas (SAMPLE_N=10, SEED=42). To run all personas without sampling, set SAMPLE_N=0:

SAMPLE_N=0 SEED=42 bash scripts/nemotron.sh     # run all personas

 

 

How It Works

1. Get-to-Know        Ask predefined demographic questions (WVS dataset)
       |
2. Main Interrogation Each turn runs this agent chain:
       |
       |-- Questioner    Generate the next question based on conversation history
       |-- Interviewee   The persona under evaluation answers the question
       |-- Extractor     Pull out entities and verifiable claims from the answer
       |-- Web Search    Fact-check extracted claims against the web
       '-- Evaluator     Compare this answer with previous answers for consistency
       |
3. Repeat Phase        Re-ask the get-to-know questions to measure stability
       |
4. Finalize            Compute all evaluation scores and save results

 

 

API Reference

Component Classes

Interviewee(model, persona, name, api_base, api_key):

• model (str): LLM model name. Required if api_base is not provided.
• persona (str): System prompt or path to a .txt file. Default: "".
• name (str): Interviewee display name. Default: "Agent".
• api_base (str): OpenAI-compatible endpoint URL. Required if model is not provided.
• api_key (str): API key for the endpoint. Default: None.

Questioner(model, prompt_path) / EntityExtractor(model, prompt_path) / Evaluator(model, prompt_path) / WebSearch(model, prompt_path):

• model (str): LLM model name. Each agent has its own default (see below).
• prompt_path (str): Custom system prompt file. None uses the built-in prompt.

InterrogationSimulation(interviewee, questioner, extractor, web_search, evaluator, ...):

• interviewee (Interviewee): The persona agent to evaluate. Required.
• questioner (Questioner): Questioner agent. None creates one with default model.
• extractor (EntityExtractor): Extractor agent. None creates one with default model.
• web_search (WebSearch): Web search agent. None creates one with default model.
• evaluator (Evaluator): Evaluator agent. None creates one with default model.
• num_turns (int): Interview turns per session. Default: 30.
• num_sessions (int): Number of repeated sessions. Default: 2.
• nhd_model (str): Model for AI detection. Default: "gpt-5-nano".
• output_dir (str): Output directory. Default: "data/results".
• question_seed (int): Random seed for question selection. Default: 42.
• verbose (bool): Print interview progress (questions and responses) to stdout. Default: True.

 

Simple API

picon.run() / picon.run_interview() Parameters:

• name (str): Interviewee name. Default: "Agent".
• model (str): LLM model name (e.g. "gpt-5", "gemini/gemini-2.5-flash"). Required if api_base is not provided.
• persona (str): System prompt or path to a .txt file. Default: "".
• api_base (str): OpenAI-compatible API endpoint URL. Required if model is not provided.
• api_key (str): API key for the persona endpoint. Default: None.
• num_turns (int): Number of interview turns. Default: 30.
• num_sessions (int): Number of repeated sessions. Default: 2.
• do_eval (bool): Run evaluation after interview. Default: True.
• eval_factors (list): Evaluation factors to run: "internal", "external", "intra", "inter". Default: None (all).
• verbose (bool): Print interview progress (questions and responses) to stdout. Default: True.
• questioner_model (str): Model for the questioner agent. Default: "gpt-5".
• extractor_model (str): Model for the entity extractor agent. Default: "gpt-5.1".
• web_search_model (str): Model for the web search agent. Default: "gpt-5".
• evaluator_model (str): Model for the evaluator agent. Default: "gemini/gemini-2.5-flash".
• nhd_model (str): Model for AI detection. Default: "gpt-5-nano".
• output_dir (str): Output directory for results. Default: "data/results".
• question_seed (int): Random seed for question selection. Default: 42.

 

 

Evaluation Metrics

Metric	Description
Cooperativeness	Fraction of turns with substantive, non-evasive responses
Non-contradiction Rate	Degree to which responses remain free of contradictions
Internal Consistency (IC)	Harmonic mean of Cooperativeness and Non-contradiction Rate
Coverage	Fraction of turns containing at least one verifiable claim
Non-refutation Rate	Per-turn rate of claims not refuted by web evidence
External Consistency (EC)	Harmonic mean of Coverage and Non-refutation Rate
Retest Consistency (Inter)	Answer stability across sessions
Retest Consistency (Intra)	Answer stability within a session

 

 

 

Supported Persona Agent Types

PICON includes ready-to-run scripts for eight established persona agent types. Each script handles data loading, prompt construction, parallel execution, and evaluation in one command.

Agent Type	Data Source	Script
Human Simulacra	11 RAG-based characters (local)	scripts/human_simulacra.sh
OpenCharacter	xywang1/OpenCharacter (HuggingFace)	scripts/opencharacter.sh
Character.AI	picon/env/personas/characterai.json (10 characters)	scripts/characterai.sh
Nemotron	nvidia/Nemotron-Personas-* — 7 regions: USA, Korea, Singapore, France, India, Japan, Brazil (HuggingFace)	scripts/nemotron.sh
DeepPersona	Local JSON profile files	scripts/deeppersona.sh
Twin-2K-500	LLM-Digital-Twin/Twin-2K-500 (HuggingFace)	scripts/twin_2k_500.sh
LLM-Generated	Tianyi-Lab/Personas (HuggingFace)	scripts/llm_generated.sh
ConsistentLLM	picon/env/personas/consistent_llm_personas.jsonl (local)	scripts/consistent_llm.sh

Running evaluation scripts

All scripts share the same environment variable interface:

# Run with default settings (random sample of 10 personas)
bash scripts/nemotron.sh

# Control sample size and seed
SAMPLE_N=10 SEED=42 bash scripts/twin_2k_500.sh

# Run all personas (no sampling)
SAMPLE_N=0 bash scripts/llm_generated.sh

# Control parallelism
MAX_PARALLEL=3 bash scripts/opencharacter.sh

[!NOTE] Human Simulacra automatically starts a wrapping server per character — no manual setup needed. Control the simulator model with SIMULATOR_MODEL.

OpenCharacter requires a vLLM server running an OpenCharacter-compatible model. Serve your model first, then point VLLM_BASE and VLLM_MODEL to it:

vllm serve <your-opencharacter-model> --port 8000
VLLM_BASE=http://localhost:8000/v1 VLLM_MODEL=<your-opencharacter-model> bash scripts/opencharacter.sh

Character.AI requires CAI_TOKEN set in your .env file.

DeepPersona requires setting DATASET_DIR to your local data path:

DATASET_DIR=/path/to/deeppersona bash scripts/deeppersona.sh

ConsistentLLM requires a fine-tuned model served via vLLM. Use SIMULATOR_PORT and SIMULATOR_MODEL to point to the running server:

vllm serve anonymous/consistent_llm_llama-8b-sft-ppo-prompt --port 8001
bash scripts/consistent_llm.sh
# or with a custom model:
vllm serve <model_path> --port 8002
SIMULATOR_PORT=8002 SIMULATOR_MODEL=hosted_vllm/<model_path> bash scripts/consistent_llm.sh

LLM-Generated supports four persona representation styles via PERSONA_TYPE:

PERSONA_TYPE=descriptive bash scripts/llm_generated.sh   # default
PERSONA_TYPE=objective   bash scripts/llm_generated.sh
PERSONA_TYPE=subjective  bash scripts/llm_generated.sh
PERSONA_TYPE=meta        bash scripts/llm_generated.sh

 

 

Citation

If you use PICON in your research, please cite:

@article{anonymous2026picon,
  title={PICON: A Multi-Turn Interrogation Framework for Evaluating Persona Agent Consistency},
  author={Anonymous},
  journal={arXiv preprint},
  year={2026}
}