ctx

ctx (Context)

ctx is a system, not a prompt.

A lightweight, file-based system that enables AI coding assistants to persist, structure, and rehydrate project context across sessions.

ctx works with any AI tool that can read files; no model or vendor lock-in.

Full documentation: ctx.ist

The ctx Manifesto

Creation, not code. Context, not prompts. Verification, not vibes.

ctx is infrastructure for preserving intent under scale. Without durable context, intelligence resets. With ctx, creation compounds.

Read the full Manifesto | ctx.ist/manifesto

The Thesis

Context as State: A Persistence Layer for Human-AI Cognition

AI-assisted development systems assemble context at prompt time using heuristic retrieval from mutable sources. These approaches optimize relevance at the moment of generation but provide no mechanism for persistence, verification, or accumulated learning across sessions. ctx treats context as deterministic state.

Read the full Thesis

Core Documents

Document	Context
Manifesto	Philosophy: creation, context, verification
The Thesis	Whitepaper: context as deterministic state
Design Invariants	System properties that must always hold
Tool Comparison	How ctx differs from .cursorrules, Aider, Copilot
ctx Blog	Deep dives, architecture notes, learnings

The Problem

Most LLM-driven development fails not because models are weak: They fail because context is ephemeral. Every new session starts near zero:

• You re-explain architecture
• The AI repeats past mistakes
• Decisions get rediscovered instead of remembered

The Solution

ctx treats context as infrastructure:

• Persist: Tasks, decisions, learnings survive session boundaries
• Reuse: Decisions don't get rediscovered; lessons stay learned
• Align: Context structure mirrors how engineers actually think
• Integrate: Works with any AI tool that can read files

Here's what that looks like in practice:

❯ "Do you remember?"

● Yes. The PreToolUse hook runs ctx agent, and CLAUDE.md tells me to
  read the context files. I have context.

❯ "What have we been working on recently?"

● Yes. I can run ctx journal source and review recent activity:
    - 2025-01-20: The meta-experiment that started it all
    - 2025-01-21: The ctx rename + Claude hooks session

That's the whole point: Temporal continuity across sessions.

Installation

Download pre-built binaries from the releases page, or build from source:

git clone https://github.com/ActiveMemory/ctx.git
cd ctx
CGO_ENABLED=0 go build -o ctx ./cmd/ctx
sudo mv ctx /usr/local/bin/

See installation docs for platform-specific instructions.

Quick Start

# Initialize context directory in your project
ctx init

# Check context status
ctx status

# Get an AI-ready context packet
ctx agent --budget 4000

# Add tasks, decisions, learnings
ctx add task "Implement user authentication"
ctx add decision "Use PostgreSQL for primary database" \
  --context "Need a reliable database for production workloads" \
  --rationale "PostgreSQL offers ACID compliance, JSON support, and team familiarity" \
  --consequence "Team needs PostgreSQL training; must set up replication"
ctx add learning "Mock functions must be hoisted in Jest"

Documentation

Guide	Description
Getting Started	Installation, quick start, first steps
CLI Reference	All commands and options
Context Files	File formats and structure
Integrations	Claude Code, Cursor, Aider setup
Recipes	Practical guides and workflows
Security	Threat model, encryption, permissions

Contributing

Contributions welcome. See CONTRIBUTING.md for guidelines.