.pixir/sessions/*.ndjson The Log is truth
Sessions persist as append-only local evidence for replay, repair, inspection, and audit.
Developer Preview · CLI/ACP
Run coding agents with a local audit trail.
Pixir is an OTP-supervised, local-first runtime for CLI and ACP-driven agent work. Keep the Log as truth, resume real sessions, inspect branches, and operate agents without turning the UI into the runtime.
pixir · local runtime
$ mix escript.install hex pixir
Resolving Hex dependencies...
Generated escript pixir with MIX_ENV=prod
$ pixir doctor --json
{"ok":true,"status":"ready","version":"0.1.0"}
$ pixir tree <session-id> --json
{"session":"...","children":[],"log":"append-only"}
Runtime spine
Sessionconversation process
Turnone provider/tool loop
ProviderResponses transport
Toolspermissioned actions
Loglocal source of truth
Why Pixir
Agent work should leave evidence you control.
Coding agents can edit files, call tools, compact context, and spawn more work. Pixir is for the moment after the answer scrolls away, when you need to know what happened, which work was partial, and what can safely continue.
pixir acp The UI is replaceable
Use the terminal, an ACP client, or dogfood through T3 Code while Pixir remains the runtime.
provider_usage Provider work is observable
Token, cache, and transport evidence is recorded as runtime evidence, not hidden chat state.
Runtime Model
Small spine. Durable consequences.
Pixir keeps the runtime model legible: Session to Turn to Provider to Tools. The model can reason, but the local Log remains authoritative; OTP supervision keeps Sessions, Turns, and Subagents as explicit runtime concerns instead of prompt conventions.
01 Start a Session
The workspace gets local runtime state and append-only Session Logs.
02 Run a Turn
Provider calls and tool results flow through one inspectable loop.
03 Inspect or continue
Resume, tree, compact, and fork use local evidence instead of a hidden store.
04 Handle partial work honestly
Timeouts, failed steps, retries, and partial Workflow outcomes stay visible.
Operator Primitives
Commands for people who operate agents, not just chat with them.
Pixir's first public surface is intentionally narrow: CLI and ACP. The primitives are built around diagnostics, continuation, and local evidence.
pixir doctor --json Check runtime, auth, config, workspace, and ACP readiness from a scriptable diagnostic gate.
pixir resume <session-id> Continue from a durable Session instead of starting over from a transcript pasted into chat.
pixir tree <session-id> --json Project the Session and Subagent hierarchy from local Logs without calling the model.
pixir compact <session-id> --dry-run --json Preview history checkpoints before appending a durable compaction boundary.
pixir fork <session-id> Branch exploration while preserving the original Session as evidence.
pixir acp Run Pixir behind ACP clients while keeping JSON-RPC stdout clean and diagnostics separate.
Design stance
The presenter boundary is part of the product.
Pixir does not need the UI to be the runtime. The CLI, ACP clients, and local T3 Code dogfood can all present work while the Log remains the authority.
Runtime first Session, Turn, Provider, Tools, and Log are the product vocabulary.
Local by default Logs, credentials, and diagnostics stay local unless an operator chooses otherwise.
Honest outcomes Detached, failed, timed-out, and partial Subagent work should not read as success.
Practices stay explicit Skills, Workflow Templates, and PATCHMD guide work without becoming hidden runtime magic.
Developer Preview
What Pixir is not yet.
Pixir is public enough to install and operate, but the contract is narrow on purpose. The site should say this plainly.
Pixir can be daily-driven through ACP, but it is not a finished standalone terminal app.
T3 Code pairing is dogfood through a local adapter, not a public install path.
Hex installs the CLI/ACP runtime; internal modules are documented for transparency.
No hosted service promises, telemetry, self-update, or enterprise support contract.
Get Started
Install the runtime. Run the diagnostic. Keep the evidence.
Start with Hex when you want the published daily-driver binary. Use a source checkout when you are working on Pixir itself.
$ mix escript.install hex pixir $ pixir doctor --json $ pixir acp