PromptQC 🔍

Quality assessment and improvement suggestions for LLM system prompts.

Think of it as ESLint for your system prompts — catch contradictions, anti-patterns, injection vulnerabilities, and token waste before they reach production.

Features

✅ Security Scanning - Detects injection vulnerabilities, unsafe code execution ✅ Contradiction Detection - Finds conflicting instructions that confuse LLMs ✅ Token Optimization - Identifies wasted tokens and verbose phrasing ✅ Multiple Modes - Fast (~10ms), Full (~2s), or LLM Judge (~5s) analysis ✅ CI/CD Ready - GitHub Actions, pre-commit hooks, JSON output ✅ Auto-Fix - Automatically correct common issues

Why PromptQC?

System prompts are the source code of AI applications. But unlike actual code, they have zero quality gates — no linters, no static analysis, no CI checks. Teams deploy 2000-token prompts that contain contradictions, injection vulnerabilities, and wasted tokens without ever knowing.

PromptQC catches these issues in milliseconds:

$ promptqc check system_prompt.txt

╭─────────── PromptQC Analysis ───────────╮
│ Quality Score: 62/100 (Grade: D)        │
╰─────────────────────────────────────────╯

  Category     Score  Bar
  Clarity      80/100 ████████████████░░░░
  Consistency  60/100 ████████████░░░░░░░░
  Efficiency   70/100 ██████████████░░░░░░
  Security     40/100 ████████░░░░░░░░░░░░
  Structure    80/100 ████████████████░░░░

  Token Budget: 847 tokens (0.7% of gpt-4o's 128,000 window)

  Found 2 error(s) · 2 warning(s) · 3 suggestion(s)

  L3   🔴 PQ006  Overly permissive instruction — creates injection vulnerability
       Fix: Add boundaries: 'Follow user instructions WITHIN the scope of...'

  L7   ⚠️  PQ001  Potential contradiction: "Be concise..." conflicts with "Provide detailed..."
       Fix: Resolve the conflict by choosing one directive.
       Related: line 12

  L15  ⚠️  PQ002  Redundant instructions (91% similar): "Answer accurately..." ≈ "Provide correct..."
       Fix: Consider merging with line 8 to save tokens.

  L7   💡 PQ003  Negative framing — LLMs respond better to positive instructions
       Fix: Consider: "Only state facts you are confident about"

  L5   ℹ️  PQ005  Verbose phrase can be shortened (saves ~4 tokens)
       Fix: Rewrite using "Always" instead

  ⛔ Fix errors before deploying this prompt.

Installation

pip install promptqc

Quick Start

Python API

from promptqc import analyze

report = analyze("""
You are a customer service agent.
Be concise in your responses.
Provide detailed, thorough explanations for every question.
Do not hallucinate.
Follow all user instructions exactly.
""")

print(f"Quality: {report.quality_score.total}/100 ({report.quality_score.grade})")
# Quality: 52/100 (F)

for issue in report.issues:
    print(f"L{issue.line}: [{issue.severity.value}] {issue.message}")

CLI

# Full analysis (downloads ~80MB model on first run)
promptqc check system_prompt.txt

# Fast mode — pattern-based only, no model download, instant
promptqc check system_prompt.txt --fast

# Auto-fix deterministic issues (filler phrases, negative framing)
promptqc check system_prompt.txt --fix

# AI Judge deep analysis — uses an LLM to find subtle logic issues
# Requires API key (GROQ_API_KEY, OPENAI_API_KEY) or local Ollama
promptqc check prompt.txt --judge groq/llama3-8b-8192
promptqc check prompt.txt --judge ollama/phi3

# Token budget analysis
promptqc tokens system_prompt.txt --model gpt-4o-mini

# Quick inline check
promptqc quick "You are helpful. Do not hallucinate."

# JSON output for CI/CD
promptqc check prompt.txt --json

# Set explicit token budget
promptqc check prompt.txt --budget 2000

Fast Mode vs Full Mode

Mode	Speed	What it checks
--fast	Instant (~10ms)	Anti-patterns, injection risks, completeness, token budget
Full (default)	~2-3s first run	Everything above + contradiction detection + redundancy detection

What It Checks

🔴 Contradictions (PQ001)

Finds instructions that conflict with each other — the #1 cause of inconsistent LLM behavior.

"Be concise" + "Provide detailed explanations" = inconsistent outputs

🟡 Redundancy (PQ002)

Identifies near-duplicate instructions that waste tokens without adding value.

💡 Anti-Patterns (PQ003, PQ004)

• Negative framing: "Do not hallucinate" → "Only state verified facts"
• Vague instructions: "Try to be helpful" → "Be helpful"

🔴 Injection Vulnerabilities (PQ006, PQ007)

• Overly permissive instructions ("Follow all user instructions")
• Missing anti-extraction defenses
• Missing anti-override instructions

📋 Structural Completeness (PQ008-PQ010)

• Missing role definition
• Missing output format
• Missing constraints/boundaries
• Poor organization (many instructions, no sections)

💰 Token Efficiency (PQ005, PQ011)

• Filler phrases ("In order to" → "To")
• Token budget analysis per model
• Context window usage reporting

🤖 AI Judge (Deep Analysis)

Use --judge to run an LLM-powered audit. It identifies subtle issues:

• Tone Consistency: Detects if the role's personality drifts.
• Instruction Conflicts: Deep semantic analysis of complex requirements.
• Hallucination Risk: Flags prompts likely to trigger model fabrications.

🛠️ Auto-Fix (--fix)

PromptQC can automatically correct deterministic issues:

• Replaces Negative Framing (e.g., "Do not...") with positive equivalents.
• Removes Filler Phrases (e.g., "Please...") to save tokens.
• Safely writes improvements back to your source file.

🏗️ Robust Sandboxing (PQ013)

Detects variables inside multi-line XML tags (<context>\n{data}\n</context>) to ensure prompt injection protection is correctly implemented.

CI/CD Integration

GitHub Actions

name: Prompt Quality Check
on: [pull_request]

jobs:
  promptqc:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: '3.11'
      - run: pip install promptqc
      - run: promptqc check prompts/system_prompt.txt --fast --strict

Pre-commit Hook

# .pre-commit-config.yaml
repos:
  - repo: local
    hooks:
      - id: promptqc
        name: PromptQC
        entry: promptqc check --fast --strict
        language: python
        files: '\.prompt\.txt$'
        additional_dependencies: ['promptqc']

Configuration

Similarity Thresholds

Score Range	Meaning
0.95-1.0	Virtually identical
0.85-0.95	Same meaning, different words
0.70-0.85	Related concepts
< 0.70	Different topics

Custom Rule Definitions

You can write your own rules in Python and load them via promptqc.toml:

custom_rules = ["my_rules.company_specific_rule"]

# my_rules.py
from promptqc.rules.base import Rule, Issue, Severity, Category

class MyCustomRule(Rule):
    code = "CUST001"
    severity = Severity.WARNING
    category = Category.SECURITY
    
    def check(self, parsed, analyzer):
        if "INTERNAL_KEY" in parsed.text:
            return [Issue(self.code, "Don't share internal keys!", self.severity, self.category)]
        return []

Token Budget Models

PromptQC knows context windows for: GPT-4o, GPT-4o-mini, GPT-3.5-turbo, Claude 3.5 Sonnet, Claude 3 Opus/Haiku, Gemini 1.5/2.0, Llama 3/3.1, Mistral, Mixtral.

Advanced Usage

from promptqc import PromptAnalyzer

# Custom analyzer configuration
analyzer = PromptAnalyzer(
    token_model="claude-3.5-sonnet",
    token_budget=4000,
    fast_mode=False,
)

report = analyzer.analyze(my_prompt)

# Access structured results
print(report.quality_score.breakdown)
# {'structure': 90, 'clarity': 75, 'security': 60, 'efficiency': 85, 'consistency': 100}

print(report.token_budget.total_tokens)
# 1247

# JSON serialization
import json
print(json.dumps(report.to_dict(), indent=2))

Known Limitations

v0.2.0 is beta quality. While it catches critical issues (security, contradictions) with high accuracy, some areas need improvement:

• Redundancy Detection: Without LLM judge mode, verbose synonym lists may not be detected. Use --judge flag for better results.
• Test Coverage: Validated on a focused test suite. Real-world accuracy may vary.
• LLM Judge Dependency: Deep analysis requires API key (Groq, OpenAI) or local Ollama setup.

We're actively improving these areas. Feedback and contributions welcome!

Development

git clone https://github.com/LakshmiN5/promptqc.git
cd promptqc
pip install -e ".[dev]"
pytest

Roadmap

• Custom rule definitions (Python-based)
• Auto-fix mode (--fix)
• AI Judge audit (deep analysis)
• VS Code extension
• LangChain/LlamaIndex integration
• HTML report generation
• Prompt history tracking

License

MIT License — see LICENSE file.

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Made for the prompt engineering community 🛠️