ctx
Instant recall for coding agents. Search the history already on your machine. Git blame, but for agent sessions.
ctx is an open-source CLI that enables coding agents to search and retrieve their own historical session transcripts, tool calls, and decisions from past work. It indexes local agent history from dozens of coding assistants (Claude Code, Cursor, Codex, Cline, Continue, and 40+ others) into a fast, searchable format that agents can query to recover context, avoid repeated work, and understand why code was written. The paid ctx pro add-on provides git-blame-style provenance, mapping any line, file, commit, or PR back to the original agent session that produced it, complete with citations to the exact transcript and tool calls.
Key Features
Use Cases
- 01Recover decisions, constraints, and assumptions from earlier agent sessions to inform current work
- 02Avoid retrying failed approaches by searching what previous sessions already explored
- 03Audit past agent sessions in detail to improve prompts, instructions, and tool configurations
- 04Resume interrupted work by finding where previous sessions left off across multiple threads
- 05Investigate why code was written a certain way by using ctx blame to surface the original session transcript
- 06Reduce token spend and repeated agent work by giving agents instant access to their own history
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ctx — FAQ
What is ctx?+
ctx is a CLI tool that indexes and searches local coding agent session histories from 40+ assistants, enabling agents to retrieve past transcripts, tool calls, and decisions. It runs entirely on your machine without cloud APIs or external data transmission.
How do I install ctx?+
On macOS and Linux, run 'curl -fsSL https://ctx.rs/install | sh'. On Windows PowerShell, run 'irm https://ctx.rs/install.ps1 | iex'. After installation, run 'ctx setup' to discover and index your local agent histories.
Which coding agents does ctx work with?+
ctx supports 40+ coding assistants including Claude Code, Cursor, Codex, Cline, Continue, Roo Code, Goose, Zed, OpenHands, Augment, GitHub Copilot CLI, Tabnine CLI, Warp, and many others. It reads their local JSONL or SQLite history files without modification.
Does ctx require API keys or send data to the cloud?+
No. ctx runs entirely locally, computing embeddings and indexing history on your machine. It does not call model APIs, require API keys, or send transcripts to external services.
Is ctx free?+
The core ctx search and indexing tool is free and open source. ctx pro, which adds git-blame-style provenance mapping code back to agent sessions, costs $20/month with a free 14-day trial (30 days via referral) requiring no credit card.
How do agents use ctx?+
Install the ctx skill for your agent (available via the open skills installer or agent plugin marketplaces), then agents can run ctx commands to search history, retrieve transcripts, and use ctx blame to trace code provenance. Agents call ctx search with terms, receive ranked results with ctx IDs, then use ctx show to retrieve full context.
How do I install ctx?+
Open the source repository on GitHub and follow its README. ctx is a skill — MCP Agents Market links you directly to the official repo.
Is ctx free?+
ctx is an open-source project hosted on GitHub. Check the repository for its license and any usage requirements.