# Crux > Compression Runtime for Universal eXecution — a 60–95% token reducer for AI coding agents (Claude Code, Cursor, Cline, …). Single Rust binary, SQLite, 11 layers, local-first. - **Type:** MCP server - **Install:** `agentstack add mcp-keradd-crux` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [Keradd](https://agentstack.voostack.com/s/keradd) - **Installs:** 0 - **Category:** [Databases](https://agentstack.voostack.com/c/databases) - **Latest version:** 0.1.0 - **License:** Apache-2.0 - **Upstream author:** [Keradd](https://github.com/Keradd) - **Source:** https://github.com/Keradd/crux ## Install ```sh agentstack add mcp-keradd-crux ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About CRUX Local-first Rust runtime for AI coding agents. Token optimization. Context hygiene. Sandboxed execution. Zero telemetry. --- ## What is CRUX? AI coding agents waste tokens re-reading files, echoing redundant tool output, and filling context with verbose prose. CRUX solves this with a layered pipeline that compresses every interaction — before it enters the agent's context window. **One binary. One SQLite database. 12 layers of optimization.** - **Token costs drop** — layered compression over tool descriptions, bash output, file reads, and conversation history. - **Context stays lean** — per-file read cache with delta replies and structural digests prevent re-reads. - **Code is searchable** — hybrid BM25 + dense vector + RRF search across code, memory, and conversation chunks. - **Execution is safe** — Linux rlimits, landlock, and optional seccomp; portable fallback on other platforms. - **Output stays clean** — comment slop guard strips AI-flavoured prose from source; humanizer rewrites raw AI output into concise text. - **Zero telemetry** — no cloud, no analytics, no network calls unless you opt in. --- ## Quick start ```bash # Install cargo install crux # Register CRUX inside every detected AI agent as an MCP server crux setup # Build with the comment-hygiene gate in front of cargo build crux build --release # Hybrid code search across the indexed project crux search "delta cache" --kind code --limit 5 # Scan the workspace for AI-flavoured comments crux hygiene comments --check # Rewrite raw AI prose into concise text crux humanize --mode concise --input "In conclusion, we leverage the robust pipeline." # → We use the pipeline. ``` Or build from source: `git clone https://github.com/Keradd/crux.git && cd crux && cargo build --release` --- ## Why CRUX? | Problem | CRUX solution | |---|---| | Agent re-reads the same files every turn | **Layer 4** — read cache with mtime tracking, delta replies, structural digests | | Tool descriptions eat context budget | **Layer 2** — description shrinker strips redundant prose from MCP tool surfaces | | Bash output is verbose and repetitive | **Layer 3** — TOML-defined filters (3-tier: static, dynamic, structured) | | Code search is slow or cloud-dependent | **Layer 6** — hybrid BM25 (porter + trigram) + dense vectors + RRF, all local | | Syntax trees are expensive to recompute | **Layer 5** — persistent tree-sitter AST graph with cross-file call resolution | | AI agents write overly verbose comments | **Layer 12** — deterministic scanner, fixer, and stripper for AI-flavoured comments | | Raw AI prose wastes tokens | **Humanizer** — deterministic local rewrite of verbose output into concise text | | Unsafe code execution blows up context | **Layer 7** — sandboxed subprocess with rlimits, landlock, seccomp | --- ## Features - **Token optimization** — layered compression across all 12 layers. - **Context hygiene** — read cache, delta replies, structural digests. - **Hybrid search** — BM25 porter + trigram + dense vectors + RRF. - **AST graph** — tree-sitter for 6 languages with cross-file call resolution. - **Sandboxed execution** — Linux rlimits + landlock + seccomp; cross-platform fallback. - **Persistent memory** — FTS5 + decay-ranked observations with contradiction detection. - **Comment slop guard** — detect, fix, and strip AI-flavoured source comments. - **Output humanizer** — rewrite raw AI prose into concise, natural text. - **MCP tooling** — stdio JSON-RPC server exposing 13 tools, plus description shrinker proxy. - **Hygiene-aware build** — `crux build` gates on comment hygiene before `cargo build`. --- ## Commands | Command | Description | |---|---| | `crux setup` | Register CRUX inside every detected AI agent | | `crux init` | Scaffold `.crux/`, `CLAUDE.md`, and project profile | | `crux index` / `crux reindex` | Build AST graph and chunk store | | `crux search ` | Hybrid BM25 + dense + RRF search | | `crux find ` / `crux impact ` | Symbol lookup and blast radius | | `crux execute --runtime ` | Sandboxed code execution | | `crux remember` / `crux recall` | Decay-ranked observation store | | `crux bash ` | Run command through the filter pipeline | | `crux hygiene comments --check\|--fix\|--strip` | AI-comment slop guard | | `crux humanize --mode ` | Rewrite AI-flavoured prose | | `crux build` | Hygiene check + `cargo build` | | `crux audit` / `crux stats` | Health snapshot and telemetry | | `crux digest` / `crux compact` | Conversation turn-event rollups | | `crux mcp` / `crux mcp-shrink` | MCP server or description shrinker proxy | `CRUX_HOME` overrides `~/.crux`. `CRUX_PROJECT` overrides project-root detection. --- ## Architecture CRUX is a layered pipeline. Each layer compresses or transforms agent interactions independently: ``` Input → L1 (Output rules) → L2 (MCP shrink) → L3 (Bash filter) → L4 (Read cache) → L5 (AST graph) → L6 (Search) → L7 (Sandbox) → L8 (Memory) → L9 (Coach) → L10 (Setup) → L11 (Digest) → L12 (Hygiene) ``` See [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) for the full design. --- ## Documentation - [Architecture](docs/ARCHITECTURE.md) — goals, tech stack, data model, per-layer internals, security model. - [Install](docs/INSTALL.md) — from-source build, `--features` matrix, per-agent activation. - [MCP tools](docs/MCP.md) — stdio server, description shrinker, full tool surface. - [Humanizer](docs/HUMANIZER.md) — modes, examples, what it never touches. - [Comment Hygiene](docs/HYGIENE.md) — scanner, fixer, stripper behaviour. - [Contributing](CONTRIBUTING.md) — workspace conventions, PR checklist, comment rules. - [Changelog](CHANGELOG.md) — release history. - [Examples](examples/) — scaffolded projects to explore. --- ## Privacy CRUX is local-first. No cloud backend, no analytics, no update ping. Telemetry lives in a local SQLite database (`$CRUX_HOME/db/crux.sqlite`, mode `0600`) and is only exposed via `crux audit` / `crux stats`. The MCP server defaults to stdio; the TCP daemon binds to `127.0.0.1`. No network calls happen unless you explicitly opt into a cloud embedder or remote transport. Secrets handling: [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) §14.2. --- ## Development MSRV: **Rust 1.96**. CI runs 5 jobs on Ubuntu + stable: ```bash cargo fmt --all -- --check cargo clippy --workspace --all-targets -- -D warnings cargo test --workspace --exclude crux-l7-sandbox RUSTDOCFLAGS="-D warnings" cargo doc --workspace --no-deps ``` Prefer `crux build` over `cargo build` — the hygiene gate runs first. See [`CONTRIBUTING.md`](CONTRIBUTING.md) for the full PR checklist. --- ## License Licensed under `MIT OR Apache-2.0` at your option: - [Apache-2.0](LICENSE-APACHE) — - [MIT](LICENSE-MIT) — Contributions are dual-licensed under the same terms. ## Source & license This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [Keradd](https://github.com/Keradd) - **Source:** [Keradd/crux](https://github.com/Keradd/crux) - **License:** Apache-2.0 Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** yes - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/mcp-keradd-crux - Seller: https://agentstack.voostack.com/s/keradd - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.