Fix Claude Context Window Problems: pctx vs Anthropic Code Mode

Solve the MCP context window problem with Code Mode execution. Both pctx and Anthropic's Advanced Tool execute tools outside the context window, but pctx is open-source, self-hosted, and works with any LLM—not just Claude.

Quick Comparison

FeaturepctxAdvanced Tool (Claude Developer Platform)
Open Source✓ MIT License✗ Proprietary
Self-Hosted✓ Your Infrastructure✗ Claude Developer Platform Only
Model Support✓ Any LLM (Claude, GPT, Gemini, local)✗ Claude Only
TypeScript Compiler✓ Built-in✗ Not Available
Local Tool Execution✓ Any LanguagePython
Runs Locally✓ Full Local Control✗ Cloud-based
Vendor Lock-in✓ No Lock-in✗ Locked to Anthropic
Programmatic Tool Calling
Sandbox Execution
MCP Support

Why Choose pctx Over Advanced Tool (Claude Developer Platform)?

1. Model Agnostic - Use Any LLM

Advanced Tool (Claude Developer Platform): Only works with Claude models via the Claude Developer Platform. You're locked into their pricing, availability, and service terms.

pctx: Works with Claude, GPT-4, Gemini, Llama, and any other LLM. Switch models anytime, use local models for privacy, or run multiple models for different tasks.

2. Self-Hosted - Your Infrastructure, Your Control

Advanced Tool (Claude Developer Platform): Cloud-based service. Your code execution happens on Anthropic's Claude Developer Platform with their security policies and compliance limitations.

pctx: Deploy on your own servers, VPC, or even laptop. Meet compliance requirements (HIPAA, SOC 2, air-gapped environments). Full control over data, execution, and security policies.

3. TypeScript Compiler Built-in

Advanced Tool (Claude Developer Platform): No TypeScript compilation support. You're limited to Python execution.

pctx: Built-in TypeScript compiler means your AI agents can write and execute TypeScript code with full type safety. Perfect for modern development workflows.

4. Local Tool Execution in Any Language

Advanced Tool (Claude Developer Platform): Limited to tools that work within the Claude Developer Platform's cloud sandbox environment.

pctx: Execute tools in Python, JavaScript, TypeScript, Rust, Go, or any language. Call local system tools, databases, internal APIs, and services that can't be exposed to external APIs.

5. Open Source MIT License

Advanced Tool (Claude Developer Platform): Proprietary. Closed source. Subject to API changes, pricing changes, and potential service discontinuation.

pctx: MIT licensed open source. Audit the code, contribute features, fork if needed. Community-driven development with no vendor lock-in or usage restrictions.

6. Runs Completely Locally

Advanced Tool (Claude Developer Platform): Requires internet connection and Claude Developer Platform access. Your workflow depends on Anthropic's service availability.

pctx: Run completely offline with local models. Perfect for air-gapped environments, development on planes/trains, or regions with connectivity issues.

The Claude Context Window Problem

If you're using Claude with MCP tools, you've likely hit this frustrating problem: your context window fills up quickly, auto-compact kicks in constantly, and your AI agent loses critical conversation history.

Why This Happens

  • MCP tool descriptions are sent with every request (even if you don't use them)
  • Tool responses can be 50K+ tokens each (search results, file contents, API responses)
  • Context fills up after 3-4 tool calls, triggering auto-compact
  • Auto-compact summaries consume 90%+ of your context window
  • You're stuck manually managing which MCP servers are active to save tokens

How Code Mode Solves This (Both Solutions)

Both Anthropic's Code Mode and pctx solve this problem the same way: tool execution happens outside the context window. MCP tool calls and responses don't consume your agent's context, so you can make unlimited tool calls without running out of space.

Without Code Mode

  • • Tool calls consume context
  • • Auto-compact after 2-3 messages
  • • Agent forgets conversation history
  • • Manual MCP server management
  • • Workflow breaks constantly

With Code Mode

  • • Execution outside context window
  • • Unlimited tool calls
  • • Agent maintains full history
  • • No manual server management
  • • Production-grade workflows

What Both Solutions Offer

Both pctx and Anthropic's Advanced Tool share the same foundational Code Mode principles that make tool execution dramatically more efficient:

Code Mode Architecture

  • • Programmatic tool calling via code APIs
  • • Sandbox security for isolated execution
  • • MCP (Model Context Protocol) integration

Performance Benefits

  • • 98.7% reduction in token usage
  • • Parallel tool execution (5-10x faster)
  • • Production-ready scalability

Ready to Switch to Open Source?

Get started with pctx today - no vendor lock-in, no usage limits, full control.