Content
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<img src=".github/assets/logo.png" alt="PCTX Logo" style="height: 128px">
<h1>pctx</h1>
[](https://portofcontext.com)
[](https://www.npmjs.com/package/@portofcontext/pctx)
[](https://www.rust-lang.org)
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The open source framework to connect AI agents to tools and services with [code mode](#what-is-code-mode)
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## Install
```bash
# Homebrew
brew install portofcontext/tap/pctx
# cURL
curl --proto '=https' --tlsv1.2 -LsSf https://raw.githubusercontent.com/portofcontext/pctx/main/install.sh | sh
# npm
npm i -g @portofcontext/pctx
```
## Quick Start
```bash
# Initialize config for upstream mcp connections
pctx init
# Connect to any MCP server
pctx add my-local-server http://localhost:3000/mcp
pctx add stripe https://mcp.stripe.com
# Start the unified MCP server in dev mode
pctx dev
# copy the pctx url and connect to agents with --transport http
```
For complete CLI documentation, see [CLI.md](docs/CLI.md).
For configuration options, see [Configuration Guide](docs/config.md).
<img width="1020" height="757" alt="Screenshot 2025-11-21 at 11 03 20 AM" src="https://github.com/user-attachments/assets/d61be46d-5a4b-40fd-953a-7dc725266e63" />
## What is pctx?
`pctx` sits between AI agents and MCP servers. It aggregates multiple upstream MCP servers, handles authentication, and exposes tools through a unified [Code Mode](#what-is-code-mode) interface. Instead of agents managing connections to individual MCP servers, they connect once to pctx.
## What is Code Mode?
Code mode replaces sequential tool calling with code execution. Rather than an agent calling tools one at a time and passing results through its context window, it writes TypeScript code that executes in a sandbox. Read Anthropic's overview [here](https://www.anthropic.com/engineering/code-execution-with-mcp).
**Traditional MCP flow**:
1. Agent calls `getSheet(id)`
2. Server returns 1000 rows → agent's context
3. Agent calls `filterRows(criteria)`
4. Server returns 50 rows → agent's context
**With Code Mode**:
```typescript
const sheet = await gdrive.getSheet({ sheetId: "abc" });
const orders = sheet.filter((row) => row.status === "pending");
console.log(`Found ${orders.length} orders`);
```
**Result:** 98.7% reduction in tokens (150k → 2k) for this multi-step operation.
## Features
- **Code Mode interface**: Tools exposed as TypeScript functions for efficient agent interaction. See [Code Mode Guide](docs/code-mode.md).
- **Upstream MCP server aggregation**: Connect to multiple MCP servers through a single interface. See [Upstream MCP Servers Guide](docs/upstream-mcp-servers.md).
- **Simple config with CLI**: Create the pctx.json config with a simple CLI. pctx.json manages auth, upstream MCPs, logging, and more. See [Config Guide](docs/config.md).
- **Secure authentication**: Source secrets from environment variables, system keychain, and external commands. See [Authentication Section](docs/config.md#authentication) in the CLI configuration docs for more details.
## Architecture
```
Runs locally • in docker • any cloud
┌─────────────────────────────────┐
│ AI Agents (Bring any LLM) │
└──────────────-──────────────────┘
│ MCP
│ • list_functions
│ • get_function_details
│ • execute
┌─────────────▼───────────────────┐
│ pctx │
│ │
│ ┌─────────────────────────┐ │
│ │ TypeScript Compiler │ │
│ │ Sandbox (Deno) │ │
│ │ │ │
│ │ • Type checking │ │
│ │ • Rich error feedback │ │
│ │ • No network access │ │
│ └──────────┬──────────────┘ │
│ │ Compiled JS │
│ ┌──────────▼──────────────┐ │
│ │ Execution Sandbox │ │
│ │ (Deno Runtime) │ │
│ │ │ │
│ │ • Authenticated MCP │ │
│ │ client connections │ │
│ │ • Restricted network │ │
│ │ • Tool call execution │ │
│ └──┬──────┬──────┬────────┘ │
└─────┼──────┼──────┼─────────────┘
│ │ │
↓ ↓ ↓
┌──────┬──────┬──────┬──────┐
│Local │Slack │GitHub│Custom│
└──────┴──────┴──────┴──────┘
```
## Security
- LLM generated code runs in an isolated [Deno](https://deno.com) sandbox that can only access the network hosts specified in the configuration file.
- No filesystem, environment, network (beyond allowed hosts), or system access.
- MCP clients are authenticated in pctx. LLMs can never see your auth.
## Update
Depending on the installation method (Homebrew/npm/cURL) the update method is different. Run `which pctx` if you are unsure what you used to install it.
```bash
# Homebrew update
brew upgrade pctx
# cURL update
pctx-update
# npm update
npm upgrade -g @portofcontext/pctx
```
## Learn More
- [Model Context Protocol (MCP)](https://modelcontextprotocol.io/)
- [Code execution with MCP by Anthropic](https://www.anthropic.com/engineering/code-execution-with-mcp)
- [Code Mode explanation by Cloudflare](https://blog.cloudflare.com/code-mode/)
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