ix.dev

Index

index is a shared, open-source monorepo of developer tools that anyone can modify. The bet: one repo everyone can edit is the fastest way for all of us to move. Add something useful, and everyone gets it.

It is one Nix flake holding ~45 packages (mostly Rust, with Python, Elixir, TypeScript, and Svelte where they fit), a corpus of NixOS modules, fleet examples, and the agent infrastructure that ties them together. Most packages have a from-source page under doc/. To explore, point Claude at this repo and ask whether anything here is useful for you.

What's inside

Agent infrastructure

The harness, governance, and tuning loop that runs coding agents (Claude Code and Codex) across the fleet under one set of rules. The house system prompt is system-prompt.nix, an ordered set of named, reviewable bindings rather than a text blob, so behavior changes land as PR diffs.

Package	What it does
claude-code / codex	Agent CLIs wrapped with the shared house prompt, MCP servers, and hooks baked in
policy	One source of tool-access rules for both wrappers (deny force-merge, block superseded builtins)
system-prompt-eval	Spawns sandboxed claude -p rollouts, scores them with an LLM judge, commits the scores
claude-hooks	Lifecycle hooks as one Rust binary; every hook fails open and silent, so a broken hook never blocks a session
subagent-cache	Memoizes read-only investigations across the team, validated by Postgres recall + a Haiku judge + file-freshness hashing
symphony	Elixir/OTP runtime orchestrating multi-repo Codex sessions from a .sym DSL, each in its own git worktree
distiller	Turns raw session transcripts into searchable, reusable lessons
pi-harnesses	Fixed agent postures: sandboxed engine, beam-search executor, skeptical prosecutor
claude-stories	A status-line row of teammate avatars, peer-discovered over Tailscale with no central server

A Nix build system rebuilt for speed

Package	What it does
nix-cargo-unit	Renders the Cargo workspace as one content-addressed derivation per rustc unit, not per crate
snix	A Rust reimplementation of Nix, built here with cargo-unit (~1100 crate builds collapse into one incremental graph)
nix-fast-build + nix-eval-jobs	Patched to correctly skip already-realized CA outputs (an ~85s cache-check floor for ~1450 units becomes ~0.1s)
oci-image-builder	Splits image "describe" from "materialize" and shards per-layer tarring, so rebuilds stay fast and deterministic
nix-web-monitor	Streams Nix's internal JSON build log into a live browser dashboard while the build runs in your terminal
blast-radius	Reports how many derivations a PR would rebuild, and why
indexbench	Gates macro-benchmark and allocation-count regressions in CI

Code intelligence and search

Package	What it does
search	Semantic code search by meaning; content-addressed, so identical files across branches share one embedding
astlog	Datalog over tree-sitter syntax trees (matches as relations, joins as rules); gates nix run .#lint
scipql	The same idea over a SCIP semantic index, so a rename never touches an unrelated same-named symbol

Terminal automation

Package	What it does
tui	A PTY driver: drive any interactive program (gdb, vim, REPLs) and read back a rendered screen, not raw escape codes. Python + Node bindings
reel	Records a terminal demo through the PTY driver and encodes it to animated AVIF/WebP (see below)
run	Records a command under a terminal session, keeping agent logs small
dashboard	A live grid of running terminals in the browser over a Loro CRDT and SSE

The demo at the top of this README is not a screen recording. reel drives a real shell through the PTY driver, rasterizes the styled grid with a flat palette and an embedded monospace face, and encodes a 60fps animated AVIF (WebP fallback). AV1's inter-frame compression keeps it around 140 KB. Regenerate it any time with nix run .#reel.

Agent-facing primitives

A Python mcp server hands all of the above to an LLM with no install step. Its one general python_exec tool runs on a single shared, persistent IPython kernel: namespace persists across calls, work can background past the foreground budget, and sessions checkpoint to disk. Bundled modules expose search, the PTY driver, a fleet cluster API (Ray, Spark, SSH fan-out to Polars frames), browser and screen control, and cloud integrations.

VMs, modules, and fleet

The layer ix publishes on top of its closed-source VM primitives: reusable, auto-discovered NixOS modules and declarative fleet helpers.

Package	What it does
vmkit	Spawns guests on macOS Virtualization.framework or Linux libkrun from one binary
chrome-vm	Runs headless Chromium inside a real VM
ix-fleet	Drives declarative multi-VM rollouts
dag-runner	Executes JSON task DAGs for parallel health checks

Quick check

nix flake show          # list every package, module, and check
nix run .#lint          # nixfmt, statix, deadnix, astlog (nix + rust)
nix build .#nginx-lifecycle-up   # realize one example fleet wrapper
nix run .#reel          # regenerate the demo above

Layout

Path	Contents
packages/	Repo-owned tools and their package-local assets: agent stack, Nix build system, search, PTY driver, MCP server, reel
packages/agent/skills/	Claude Code skills shipped to agents by the skills flake package
packages/indexbench/filesystem/	Filesystem benchmark source for the bench-filesystem package
packages/sdk/	Source-available SDK bindings and SDK-specific checks
packages/maintainers/scripts/	Repo maintenance scripts that are packaged or called by flake outputs
modules/	Opt-in NixOS service modules and profiles, auto-discovered
lib/	Shared Nix APIs and reusable builders only; package-specific glue stays with its package
doc/	From-source documentation, one page per package
examples/	Standalone consumer fleets and copyable mkDev composition patterns
rfcs/	Architecture decision records

Feedback

Bug reports and enhancement requests go to GitHub Issues. Security reports follow SECURITY.md. Code changes land through pull requests against the main branch; see CONTRIBUTING.md for local setup, coding standards, and commit conventions.

Contributor notes

See AGENTS.md and CONTRIBUTING.md when you're ready to dig in.