ManuHub.PromptKit

A lightweight, production-ready .NET library for building dynamic prompt templates with clean, fluent APIs.

No AI dependencies. No vendor lock-in. Just clean prompt composition.

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🚀 Why this exists

AI apps constantly suffer from:

• messy string templates
• duplicated prompts
• hard-to-debug variable issues
• no prompt version control
• unclear final output

PromptKit solves this.

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✨ Features

• Fluent prompt builder API
• File-based prompt loading
• Object/model binding
• Prompt composition system
• Debugging & diagnostics tools
• Token estimation helper
• Serialization support (JSON)
• Fully testable architecture
• No external dependencies

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📦 Installation

dotnet add package ManuHub.PromptKit

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⚡ Quick Start

using ManuHub.PromptKit;

var result = Prompt.From("Hello {{name}}")
    .Set("name", "Manoj")
    .Render();

Console.WriteLine(result);

Output: Hello Manoj

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📁 File-based prompts

var prompt = PromptLoader.Load("prompts/email.prompt")
    .Set("name", "Sarah")
    .Set("body", "Welcome!")
    .Render();

email.prompt content:

Subject: Welcome, {{name}}!
Body: Hi {{name}},\n\nWelcome to our service!\n\nBest regards,\nThe Team

Output:

Subject: Welcome, Sarah!
Body: Hi Sarah,

Welcome to our service!

Best regards,
The Team

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🧠 Object binding

var result = Prompt.From("Hello {{name}}")
    .SetModel(new { name = "Alex" })
    .Render();

Output: Hello Alex

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🧩 Prompt composition

var final = PromptComposer.Combine(
    Prompt.From("System: You are helpful assistant."),
    Prompt.From("User: Summarize {{text}}").Set("text", article)
);

Output:

System: You are helpful assistant.
User: Summarize [article content]

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🐛 Debugging

var debug = Prompt.From("Hello {{name}}")
    .Debug();

Console.WriteLine(debug.FinalPrompt);
Console.WriteLine(string.Join(",", debug.MissingVariables));

Output:

Final Prompt: Hello {{name}}
Missing Variables: name

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📊 Token estimation

var tokens = prompt.EstimateTokens();

Output: Estimated tokens: 5

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💾 Serialization

var json = PromptSerializer.ToJson(prompt);
var restored = PromptSerializer.FromJson(json);

Output:

Serialized Prompt: {"Template":"Hello {{name}}","Variables":{"name":"Manoj"}}
Restored Prompt: Hello {{name}}

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🧪 Testing

Fully covered with xUnit tests.

dotnet test

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🏗️ Architecture

• Immutable Prompt core
• Snapshot-based serialization
• Fluent API design
• Zero dependency design

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📌 Roadmap (future)

• Prompt caching system
• Prompt versioning system
• Prompt performance profiler
• Memory extension package (PromptKit.Memory)

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📜 License

MIT