# billion-context — AI Coding Tool Review & Pricing

> billion-context is a context-compression proxy and plugin for AI coding agents that sits between the agent and its Anthropic- or OpenAI-compatible model API. It injects context-management tools so the model itself decides when and what to fold into layered, reversible summaries, keeping long sessions inside a small context window while preserving the prompt-cache prefix.

Source: https://ai.dosa.dev/tools/billion-context · Updated Oct 15, 2026 · Category: Developer Productivity & Workflow · Published by dosa.dev

## At a glance

- **Tool**: billion-context
- **Company**: ranxianglei
- **Category**: [Developer Productivity & Workflow](https://ai.dosa.dev/category/productivity)
- **Pricing model**: Free
- **Official website**: https://github.com/ranxianglei/billion-context

## Key features

- Model-driven incremental compression via injected compress, decompress, search_context and acp_status tools
- Reversible, prefix-cache-friendly summaries targeting ~5x fewer tokens and month-long single sessions within a 100K window
- Launchers and native plugins via the `bili` CLI (`bili claude`, `bili codex`, `bili opencode`, `bili pi`, `bili plugin install <host>`)
- Broad host support: Claude Code, Codex, OpenCode, pi, Gemini CLI, Qwen Code, Kimi, Hermes, Aider, GitHub Copilot CLI, Amp and more
- Built on the open acp-kernel compression engine with an accompanying open preprint and cache-health diagnostics (`/acp`, `/acp-cache`)

## Pricing

**Model**: Free

Free and open source under the MIT License with an added attribution term for products that incorporate it. You keep paying your own model provider; the proxy aims to reduce token usage rather than add fees.

## Who it is for

- **Best for**: Developers running very long coding-agent sessions who hit context-window limits or high token bills and want compression that the model controls and can undo.
- **Not ideal for**: Users who cannot route agent traffic through a local proxy or certificate MITM for closed-binary hosts, or teams whose products cannot meet the license's visible-attribution requirement.

## Verdict

An ambitious, actively maintained context-compression layer with unusually broad agent coverage and a published methodology; worth trying for marathon sessions, with the caveats of proxy setup and an attribution-bearing license.

## Recent updates

Ships frequent releases (v0.1.197 on October 14, 2026) and trended on GitHub's weekly chart in mid-October 2026; recent work expanded native plugins for hosts such as Kimi Code, Hermes and zcode.

## Frequently asked questions

### Is billion-context free?

Yes - billion-context is Free. Free and open source under the MIT License with an added attribution term for products that incorporate it. You keep paying your own model provider; the proxy aims to reduce token usage rather than add fees.

### Is billion-context open source?

billion-context is not listed as open source on ai.dosa.dev - it is Free.

### Who is billion-context best for?

Developers running very long coding-agent sessions who hit context-window limits or high token bills and want compression that the model controls and can undo.

### Who is billion-context not ideal for?

Users who cannot route agent traffic through a local proxy or certificate MITM for closed-binary hosts, or teams whose products cannot meet the license's visible-attribution requirement.

### What are the best billion-context alternatives?

The closest billion-context alternatives on ai.dosa.dev are Pieces for Developers, agenttrace, Vibe Kanban - all listed under Developer Productivity & Workflow.

### Who makes billion-context?

billion-context is developed by ranxianglei. It is listed in the Developer Productivity & Workflow category on ai.dosa.dev.

## Top alternatives

- [Pieces for Developers](https://ai.dosa.dev/tools/pieces-for-developers) (Freemium) — Developers and teams who need to manage disparate workflow context, revisit past coding decisions, and maintain consistent documentation across multiple tools and projects.
- [agenttrace](https://ai.dosa.dev/tools/agenttrace) (Open Source) — Developers who need a privacy-conscious way to audit, monitor, and diagnose the behavior, costs, and performance of various AI coding agents locally.
- [Vibe Kanban](https://ai.dosa.dev/tools/vibe-kanban) (Free) — Solo developers and individual power users who need to run multiple AI coding agents in parallel while managing separate git worktrees and tasks locally.
- [ai-memory](https://ai.dosa.dev/tools/ai-memory) (Open Source) — Developers who frequently switch between multiple AI coding agents or machines and want a unified, persistent knowledge base that survives session ends and tool switches.
- [smolvm](https://ai.dosa.dev/tools/smolvm) (Open Source) — Running untrusted code, powering coding agents with persistent/resettable workspaces, and deploying portable VM-based workloads that require a real Linux kernel.
- [coop](https://ai.dosa.dev/tools/coop) (Open Source) — Security-conscious developers who want to run autonomous coding agents on real projects without risking host machine compromise.
- Full alternatives guide: https://ai.dosa.dev/tools/billion-context/alternatives