How I Use ChatGPT and Codex for ASP.NET Core Development

Over the last year, AI has become a regular part of my development workflow. Like many developers, I started with ChatGPT for answering questions, generating code snippets, and learning new concepts. Today my workflow has evolved — instead of one tool for everything, I use ChatGPT and Codex together while building ASP.NET Core applications.

Many people think AI is about generating code faster. In reality, the biggest benefit I have experienced is faster decision-making — less time searching for answers, less time stuck on problems, and less time writing boilerplate. That frees you to focus on what actually matters: building reliable software that solves real business problems.

"The biggest change AI has brought to my workflow is not faster coding. It's faster decision-making."

AI Does Not Replace Development Knowledge

Before discussing tools, something important needs to be said clearly: AI does not replace software engineering fundamentals. You still need to understand:

  • Database design and normalization
  • API architecture and patterns
  • Security and authentication / authorization
  • Performance optimization
  • Application design patterns
  • Business requirements analysis

AI can accelerate development, but it cannot replace technical judgment. The stronger your technical knowledge, the better results you will get from any AI tool.

Core principle: AI is a collaborator that amplifies your thinking — not a replacement for it. You remain responsible for every line that ships to production.

Phase 1 — Starting with Requirements

One of the biggest mistakes developers make is jumping directly into coding. When I receive a new requirement, I always start with ChatGPT — before a single file is opened.

A client might request something that sounds straightforward:

"We need a customer loyalty system with cashback, rewards, transactions, multiple outlets, and reporting."

But requirements like this always have hidden complexity. I use ChatGPT to surface it before development begins:

  • How is cashback calculated — at vendor level or outlet level?
  • Can multiple rewards be combined in a single transaction?
  • What happens when a transaction is refunded?
  • Do rewards expire, and how is expiry enforced?
  • Who has admin access, and what can they override?

Catching these gaps in conversation costs minutes. Discovering them mid-implementation costs days.

Phase 2 — Designing the Database

After understanding the requirements, I move to database design — and I bring ChatGPT along as a second reviewer. I sketch entity relationships and table structures, then ask it to pressure-test them:

  • Are there normalization issues I have missed?
  • Is there a missing entity that will cause problems later?
  • How does this schema handle the edge cases we identified in requirements?

The final schema is always my responsibility. But ChatGPT has a useful habit of surfacing scenarios I had not fully considered — the kind that become expensive to fix once data is in production.

Phase 3 — Planning Before Coding

Before implementation starts, I use ChatGPT to break the feature into clearly scoped tasks. For a loyalty module, that might look like this:

  • Create customer, cashback rule, reward, and transaction entities
  • Implement repository and service layers for each
  • Build and document REST APIs
  • Create admin management screens
  • Build reporting views and exports
๐Ÿ’ก Tip: This planning step often saves more time than any code generation. A well-scoped task list means you never lose track of where you are in a feature, and it makes progress visible to the whole team.

Phase 4 — Where Codex Fits In

Once requirements, schema, and task breakdown are solid, I switch to Codex. This is where the biggest productivity gains appear.

What makes Codex different from traditional AI tools is its awareness of the existing project. It can inspect controllers, services, repositories, models, DTOs, and configuration files. Because it understands how the project is already structured, the code it generates fits naturally rather than requiring a major rewrite to integrate.

For a transaction listing module, I can ask Codex to create repository methods, wire up the service layer, implement pagination and filtering, and update the API endpoints — across multiple files, in one pass. What would take hours of repetitive typing takes minutes.

How I Split the Two Tools

One lesson I learned quickly: ChatGPT and Codex should not be used for the same tasks. ChatGPT is better for discussion and planning. Codex is better when the implementation task is already clear. Using each tool for its strengths makes both more effective.

๐Ÿ’ฌ ChatGPT

  • Requirements discovery
  • Architecture planning
  • Database design review
  • Feature decomposition
  • Exploring trade-offs
  • Debugging discussions
  • Learning new concepts

⚙️ Codex

  • Feature implementation
  • Cross-file refactoring
  • Bug fixes
  • Repetitive coding tasks
  • Project-wide changes
  • Code review suggestions
  • Test generation
Think first with ChatGPT. Build second with Codex.

A Quick Note on Plus Plan Usage

One practical point I learned while using ChatGPT Plus is that Codex should be used carefully. Codex is powerful, especially when it works with the actual project source code, but complex implementation tasks can consume usage much faster than normal ChatGPT discussions.

Because of that, I do not use Codex for long requirement discussions, general brainstorming, or architecture debates. I first use ChatGPT to understand the requirement, compare approaches, design the database, and break the work into small tasks.

Once the task is clear, I move to Codex for implementation. This helps me plan my day and week better, especially when I know I have larger coding tasks ahead. In simple words, I try not to spend Codex usage on conversations that can be handled properly in ChatGPT.

My simple rule: Do the thinking in ChatGPT. Use Codex when the task is ready to build.

Debugging with AI

Both tools earn their place when something breaks. My debugging process starts with ChatGPT: I describe what I am trying to do, share the error message, paste the relevant code, and explain the expected behavior. Even when it does not produce an immediate answer, the process of articulating the problem clearly often uncovers the issue itself.

Common culprits that get resolved quickly this way:

  • Incorrect dependency injection configuration
  • Missing or wrong application settings
  • Entity Framework relationship misconfigurations
  • Serialization / deserialization issues
  • Authentication and middleware ordering mistakes

Code Review and Refactoring

After implementing a feature, I sometimes use ChatGPT as a reviewer. I ask whether the approach is maintainable, whether there is unnecessary complexity, and whether there are edge cases I have missed. Questions I commonly ask:

  • Is this approach maintainable at scale?
  • Can this logic be simplified?
  • Are there potential performance issues here?
  • Is there duplicated code that could be extracted?

I do not follow every suggestion blindly. But AI occasionally catches things that would have become tech debt — think of it as having a second developer review your work before you submit.

What AI Still Gets Wrong

Despite how useful AI has become, it is not perfect. I have seen AI tools:

  • Generate inefficient SQL queries that work but will not scale
  • Suggest patterns that introduce security vulnerabilities
  • Misinterpret a business rule when context is ambiguous
  • Produce code that compiles cleanly but solves the wrong problem
  • Add unnecessary complexity when a simpler solution exists
⚠️ Important: Nothing generated by AI goes into production without review. AI is an assistant. The developer remains accountable for every decision made.

Final Thoughts

Working effectively with AI tools is becoming as important as knowing your framework. Not because AI writes your software for you — it does not — but because it removes the friction that slows you down at every other step.

ChatGPT helps me think through problems. Codex helps me implement solutions. Together, they allow me to focus more on what actually matters: building reliable software that solves real business problems.

"The AI revolution is not coming. It is here. The question is whether you will use it to think better — or just type faster."

Becoming an AI Expert in the Modern Era

AI Expert

Every developer today faces a choice: adapt to AI or get left behind. But here's the truth most won't tell you: becoming an AI expert isn't about learning to use ChatGPT. It's about understanding how to architect systems that combine your code with AI capabilities, optimize for cost at scale, and ship products that actually work in production.

This guide cuts through the noise and shows you exactly what matters.

The Honest Reality Check

"AI won't replace programmers. But programmers who use AI will replace those who don't."

You're not competing with AI. You're competing with developers who know how to work alongside it. The good news? Most developers are still typing vague prompts and wondering why they get mediocre results. You're about to learn better.

Your Complete AI Learning Roadmap

Here's the exact path to becoming an AI expert. Not theory-focused research. Not syntax memorization. Practical skills that ship products.

#Learning PhaseCore SkillsEnd Goal
1AI CollaborationPrompt engineering, requirement writing, context management, task breakdownUse AI as collaborator + implementation partner
2AI FundamentalsTokens, embeddings, context windows, hallucinations, temperatureUnderstand why AI behaves certain ways
3API IntegrationOpenAI/Anthropic APIs, streaming, function calling, structured outputsBuild AI-enabled applications
4RAG SystemsEmbeddings, chunking, vector databases, retrieval pipelinesBuild AI using custom/company data
5AI AgentsAgent workflows, multi-agent systems, tool usage, orchestrationBuild AI that performs tasks autonomously
6AI ReliabilityOutput validation, hallucination detection, guardrails, cost optimizationMake AI systems production-ready
7AI Product ThinkingWhere AI helps vs normal code, human+AI workflows, UX patternsBuild useful products, not just demos
8Real ProjectsChatbots, search systems, automation workflows, dashboardsGain actual experience

This is your roadmap. Now let's break down what actually matters in each phase.

Phase 1: Learn How to Work With AI (Most Important)

This is your foundation. Everything else builds on this.

What You're Learning

  • Prompt Engineering: Zero-shot, few-shot, chain-of-thought prompting; system prompts vs user prompts; structured output generation
  • Requirement Writing: Breaking vague requests into specific tasks; defining constraints and success criteria
  • Context Management: What to include vs what to skip; managing conversation history; token-efficient context injection
  • Task Breakdown & Validation: Splitting complex problems into AI-friendly steps; spotting hallucinations; building validation into workflow

The Simple Framework

ElementWhat to Include
Role"Act as a senior developer / technical writer / data analyst"
ContextYour tech stack, constraints, background information
TaskExactly what you want (be specific)
FormatHow the output should look (JSON, code, bullets, etc.)

Before & After Examples

❌ Weak Prompt
Write a REST API endpoint

Result: Generic code, wrong version, no error handling

✅ Strong Prompt
You are a senior developer. Write a .NET 8 minimal API endpoint 
for GET /api/users/{id}. Include async/await, return 404 if not found, 
use dependency injection, add XML comments. Return as complete working code.

Result: Production-ready output

๐Ÿ’ก Key Insight
Treat prompts like code—version control them, test them, refactor them.

Goal: Use AI as your collaborator, advisor, and implementation partner—not just a search engine.

Phase 2: Understand How AI/LLMs Work

You don't need a PhD. You need practical understanding.

What You're Learning

Core Concepts:

  • Tokens — Why they cost money and limit processing
  • Context windows — Why you can't dump entire codebases
  • Embeddings — How meaning becomes numbers
  • Temperature — Why same prompt gives different outputs
  • Hallucinations — Why AI confidently makes things up

Advanced Concepts: Vector search and similarity, RAG basics (preview for Phase 4), fine-tuning concepts, AI memory and session management

"You can't debug what you don't understand."

When AI returns garbage, you need to know if it's:

  • Your prompt structure (fix: Phase 1 skills)
  • Token limit overflow (fix: chunking)
  • Model hallucination (fix: validation)
  • Wrong temperature (fix: parameters)
๐Ÿ“š Free Resource
Andrej Karpathy's "Neural Networks: Zero to Hero" on YouTube

Goal: Understand why AI behaves certain ways so you can control it better.

Phase 3: Learn AI APIs & Integration

Pick one API (OpenAI, Anthropic) and build something real. A CLI tool, bot, anything that makes actual calls.

What You're Learning

  • OpenAI/Anthropic API basics
  • Streaming responses for better UX
  • Function/tool calling
  • Structured outputs with schemas
  • Chat history handling
  • AI workflow orchestration

What You'll Learn the Hard Way

ChallengeSolution
APIs failImplement error handling
Rate limits existUse exponential backoff
Tokens cost moneyTrack usage from day one
Responses take timeStream for better UX
๐Ÿ’ก Pro tip
Start with a code review CLI tool. It teaches error handling, token management, and practical prompting all at once.

Goal: Build AI-enabled applications that actually work.

Phase 4: Learn RAG (Very Important)

RAG (Retrieval-Augmented Generation) is how you give AI access to your data without fine-tuning or blowing your context window.

What You're Learning

  • Document embeddings
  • Chunking strategies (semantic, fixed, recursive)
  • Vector databases (try Chroma—free and local)
  • Retrieval pipelines
  • Knowledge base systems

Basic RAG Flow

User Question
    ↓
Generate embedding
    ↓
Search vector database
    ↓
Retrieve relevant chunks
    ↓
Add to prompt as context
    ↓
Generate answer from AI

Simple Test Project

Build semantic search over your documentation:

  1. Chunk docs into paragraphs
  2. Generate embeddings for each chunk
  3. Store in Chroma (runs locally)
  4. Embed user questions
  5. Find most similar chunks
  6. Return as results

Why it matters: This is the pattern behind 90% of production AI apps—documentation bots, customer support, code assistants.

Goal: Build AI using custom/company/user data.

Phase 5: Learn AI Agents

Agents take AI from reactive to proactive. They plan, use tools, and complete multi-step tasks.

What You're Learning

  • Agent workflows (ReAct, Plan-and-Execute)
  • Multi-agent systems
  • Planner/executor/reviewer patterns
  • Tool usage by AI
  • Agent memory (short-term and long-term)
  • Agent orchestration

Critical Skills

  • Designing reliable tool interfaces
  • Handling tool execution failures
  • Preventing infinite loops
  • Implementing safety guardrails

Goal: Build AI systems that perform tasks autonomously.

Phase 6: Learn AI Evaluation & Reliability

Making AI systems production-ready requires validation, monitoring, and cost management.

What You're Learning

Reliability Skills
  • Output validation
  • Hallucination detection
  • Guardrails and safety
  • Prompt testing
  • Logging and monitoring
Cost Optimization
  • Token accounting
  • Caching strategies
  • Progressive retrieval
  • Context compression
  • Smart model selection

Goal: Make AI systems reliable enough for production.

Phase 7: Learn AI Product Thinking

Not every problem needs AI. Learn when to use it and when traditional code is better.

Key Question

Does this problem benefit from:

Use CaseBest Solution
Pattern recognition→ AI
Deterministic logic→ Traditional code
Natural language processing→ AI
Precise calculations→ Traditional code

Goal: Build useful AI products, not just AI demos.

Phase 8: Practice With Real AI Projects

Theory means nothing without practice. Build these:

ProjectWhat You'll Learn
AI ChatbotBasic conversation flow, context management
AI SearchRAG, embeddings, retrieval pipelines
AI Code ReviewerStructured analysis, validation
AI AutomationWorkflows, error handling, reliability
AI AssistantMulti-turn conversations, memory
AI DashboardData presentation, insights generation
Multi-Agent SystemAgent coordination, complex workflows

Pick One and Build It This Week

  • ๐Ÿ“‹ Code Review CLI - Upload files, get AI feedback
  • ๐Ÿ“š Docs Chatbot - Semantic search over documentation
  • ๐Ÿ” Note Search - Vector search through notes
  • ๐Ÿค– Simple Agent - Bot that calls APIs and returns data

Goal: Real experience shipping AI features.

Token Optimization: Saving Money at Scale

Once you're building real systems, token costs explode. Here's how to cut them by 60-70%.

Smart Chunking

❌ Naive Approach

Retrieve top 10 chunks every time

✅ Optimized Approach

Start with 3, expand only if confidence is low

Use semantic chunking. Implement parent-child relationships. Retrieve small, expand when needed.

Multi-Level Caching

Cache TypeWhat It StoresSavings
Embedding cacheText → vector mappingsAvoid re-embedding
Retrieval cacheQuery → chunksSkip vector search
Response cacheQuestion → answerZero tokens on hit
Semantic cacheSimilar questions → adapted answersBiggest wins

Progressive Retrieval

Start with 3 chunks → Check confidence → 
Expand to 10 if needed → Generate answer

Most queries don't need everything. Start minimal.

Context Compression

Before sending to the model:

  • Remove redundant info across chunks
  • Summarize less relevant sections
  • Extract only key sentences
  • Cut tokens by 40%

Model Selection

"Not every query needs GPT-4."

Simple questions → smaller model (faster, cheaper)
Complex reasoning → larger model (smarter, expensive)

Build a router. This alone cuts costs by 50%.

Practical AI Development Workflow

✅ Good Daily Habits

  • Use AI for boilerplate and repetitive code
  • Generate test cases and documentation
  • Get code review suggestions
  • Analyze unfamiliar codebases
  • Debug with AI-assisted analysis

❌ Common Mistakes

  • Blindly copy-pasting without understanding
  • Trusting AI for security without review
  • Forgetting AI hallucinates
  • Skipping error handling

The Five Rules That Matter

  1. AI is a tool, not magic. You still need to understand what you're building.
  2. Validate everything. AI hallucinates. Check outputs for critical code.
  3. Design for failure. APIs fail. Rate limits hit. Handle gracefully.
  4. Optimize cost early. Implement caching from day one.
  5. Stay current. AI evolves fast. Keep learning.

What You're Actually Becoming

You're NOT becoming:
  • AI theory researcher
  • Syntax memorizer
  • Model trainer only
You're becoming:
  • AI Collaborator - Work with AI effectively
  • AI Architect - Design AI-powered systems
  • AI Operator - Ship and maintain AI in production

The Bottom Line

"The quality of your AI integration is directly proportional to your understanding of how it works."

Developers succeeding in AI aren't the ones with the most courses or certifications. They're the ones who:

  • Ship working AI features in production
  • Debug when things break
  • Know when to use AI vs traditional code
  • Optimize for cost without sacrificing quality

You don't need to learn everything. You need to start building, break things, fix them, and understand why they work.

The AI revolution isn't coming. It's here. Start now.

Now go build something.

AI for .Net Developers

AI for .NET Developers

Best prompt templates across 6 everyday scenarios
Copy Adapt Validate Ship faster

Vague prompts produce vague code. AI tools like Claude, GitHub Copilot, and ChatGPT are only as good as the context you give them. Developers who specify their .NET version, libraries, architecture, and expected output consistently get production-ready results — those who don't get generic boilerplate. These templates fix that.

"Fix this" → AI freezes.
Context + task + constraints → impressive output.
Stop wasting prompts. Better prompts = better code, faster delivery, fewer rewrites.
Code Generation
"Create a .NET 8 minimal API with CRUD, validation, and proper error handling."
"Write a generic repository pattern using EF Core with async methods."
"Generate a Blazor data table (MudBlazor) with sorting, pagination, and search."
Always specify: .NET version + libraries (EF Core, MediatR, MudBlazor…)
๐Ÿ›
Debugging
"Here is my stack trace: [paste]. Identify root cause and provide a fix with explanation."
"My LINQ query returns incorrect results. Find the logical issue."
"Why does this async/await code deadlock? Rewrite it safely."
Include: actual error message + relevant code snippet
๐Ÿ—️
Architecture
"Design a scalable microservices architecture using .NET + Azure Service Bus."
"Compare Clean Architecture vs Vertical Slice for a team of 5 developers."
"Suggest CQRS + MediatR structure with domain events."
Mention: team size, scale (startup/enterprise), cloud provider
๐Ÿงช
Testing
"Write xUnit tests using Moq for this service (include edge cases)."
"Generate integration tests using TestContainers + WebApplicationFactory."
"My test is flaky. Identify timing issues and fix them."
Define: framework (xUnit/NUnit) + mocking lib (Moq/NSubstitute)
๐Ÿš€
Performance
"Optimize this LINQ query for better performance (compiled queries or raw SQL)."
"Identify memory leaks and suggest IDisposable / using patterns."
Provide: benchmark data + query size / dataset context
๐Ÿ”
Code Review
"Review this C# class for SOLID violations and suggest refactoring."
"Check for security issues (SQL injection, insecure deserialization, etc.)."
Ask for: SOLID, DRY, YAGNI + security + performance review
The perfect prompt formula
Context + Task + Constraints + Output format
"I'm using .NET 8 + EF Core + PostgreSQL. Write a paginated product query with filtering.
Return clean C# code with XML comments + a usage example."

Context Is Everything — Mastering the Context Window


What Is a Context Window?

Every AI model has a context window — the total amount of text it can "see" and work with in a single conversation. Think of it as the model's working memory. Everything inside it — your instructions, the conversation history, documents you paste, and the model's own responses — counts toward this limit.

Once you exceed it, the model starts to forget. Earlier parts of the conversation get pushed out. Instructions you gave at the start may no longer be active. Outputs get worse, and often in ways that aren't obvious until something breaks.

Context windows in 2026 (approximate):

ModelContext Window
Gemini 3 Pro1,000,000 tokens (~750,000 words)
Claude Opus / Sonnet200,000 tokens (~150,000 words)
ChatGPT GPT-5.2128,000 tokens (~96,000 words)
Grok 4.1128,000 tokens (~96,000 words)

A token is roughly ¾ of a word. So 128,000 tokens ≈ a short novel. That sounds like a lot — and it is — but large codebases, long documents, and extended conversations fill up faster than you'd expect.


Why Large Context ≠ Reliable Context

Here's what most people get wrong: a bigger context window doesn't mean the model uses all of it equally well.

Attention degrades over distance. Research consistently shows that models pay more attention to content at the beginning and end of a prompt than content buried in the middle. If you paste a 50-page document and ask a question about page 23, the answer will be less reliable than asking about page 1 or page 50.

This is called the "lost in the middle" problem — and it's real across all current models, even Gemini's 1M token window.

Practical rule: The most important instructions and context should always be at the beginning or end of your prompt, not buried in the middle.


What Goes Into Your Context (And What Doesn't)

Everything you type, everything the model responds, every document you paste — all of it consumes context tokens. This adds up quickly in long conversations.

What eats context fast:

  • Large code files pasted directly
  • Long documents or PDFs
  • Extended multi-turn conversations
  • Detailed system prompts
  • Few-shot examples with long inputs/outputs

What doesn't consume context:

  • Files uploaded to the model's file storage (not pasted in chat)
  • External databases the model can query
  • The model's training knowledge (this is baked in, not in your window)

Structuring Long Prompts Without Losing Accuracy

Put Critical Instructions Last (or First — Not Middle)

If you have a long prompt with a document in the middle, put your specific question/instruction after the document, not before it.

❌ Weak structure:

"Summarize the key risks. Here is the 20-page report: [report]"

✅ Stronger structure:
"Here is the 20-page report: [report]

Based only on the above report:
1. List the top 3 financial risks mentioned
2. Identify any mitigation strategies proposed
3. Note anything the report considers out of scope"

The instruction at the end gets stronger attention than the same instruction at the beginning of a long context.

Use Clear Delimiters to Separate Content

When your prompt has multiple parts — instructions, context, data, examples — separate them visually. This helps the model parse what is instruction vs what is input.

## INSTRUCTIONS

You are reviewing a contract. Identify any clauses that limit liability 
for the service provider. Be specific about clause numbers.

## CONTRACT TEXT
[paste contract here]

## YOUR TASK
List each liability-limiting clause with: clause number, summary, 
and risk level (High / Medium / Low).

XML tags work well too, especially for Claude:

xml

<instructions>
Translate the following text to formal Hindi. 
Preserve all technical terms in English.
</instructions>

<text>
[content to translate]
</text>

Managing Multi-Turn Conversations

In long conversations, the model carries everything forward. This is useful — until it isn't.

The drift problem: After 20+ back-and-forth messages, the model can lose track of constraints you set early on. It may start contradicting earlier instructions or producing less consistent output.

Fix 1 — Summarize and restart. For long working sessions, periodically summarize what's been decided and start a fresh conversation with that summary as context:

"Let's start fresh. Here's a summary of what we've established so far:

- We're building a REST API in Node.js with TypeScript
- Authentication is JWT-based, tokens expire in 24h
- Database is PostgreSQL with Prisma ORM
- Error responses follow this schema: { error: string, code: string }

Now let's continue with: [next task]"

Fix 2 — Restate critical constraints periodically. If you're in a long coding session and accuracy matters, restate your key constraints every few messages:

"Reminder: we're using TypeScript strict mode, no any types, 

all async functions must have explicit error handling.
Now please implement: [feature]"

Fix 3 — New conversation per task. For distinct tasks, start a new conversation rather than appending to an existing one. It's cleaner, cheaper (if on API), and produces better results.


What To Do When Your Input Is Too Large

Sometimes you genuinely have more content than fits in the context window. Here are practical approaches:

Chunking

Split large documents into sections and process them individually. Then combine the outputs.

"This is part 1 of 4 of a legal document. 

Summarize the key obligations in this section only.
[section 1]"

Then repeat for sections 2, 3, 4. Finally:

"Here are summaries of 4 sections of a legal document:

[summary 1]
[summary 2]
[summary 3]
[summary 4]

Now give me a final consolidated summary of the key obligations 
across the entire document."

Extract Before You Prompt

Don't paste an entire document when you only need part of it. Extract the relevant section first.

❌ Pasting a 200-page annual report to ask about Q3 revenue


✅ Copying just the Q3 financial summary section (2-3 pages) 
   and asking your question on that

Use the Right Model for the Job

For genuinely large-context tasks — processing entire codebases, long legal documents, large datasets — Gemini 3 Pro's 1M token window is currently the most capable. For tasks requiring deep reasoning on a focused input, Claude or GPT-5.2 Thinking will outperform despite smaller windows.


Context Window Cheat Sheet

SituationWhat To Do
Long document analysisPut instructions after the document, not before
Multi-step conversation going staleSummarize and start fresh
Input too large to fitChunk it, process in parts, combine outputs
Critical constraints getting ignoredRestate them at the end of your prompt
Processing entire codebasesUse Gemini 3 Pro for its 1M window
Deep reasoning on focused inputUse Claude Opus or GPT-5.2 Thinking
Multiple documents to cross-referenceUse Claude (most reliable at long-context reasoning)

The Core Principle

A context window is not a bucket you fill up. It's a spotlight — brightest at the edges, dimmer in the middle. Structure your prompts accordingly, keep them focused, and refresh them when conversations run long.

The models are powerful. Give them the right context in the right structure, and they'll consistently deliver.