ctx (Context)
ctxis 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.