xcb

Excalibur (xcb) brings your coding-agent accounts, model choices, sessions, and usage into one local terminal workspace. Choose an account, work on your project, and pick up where you left off without changing interfaces.

The native Rust app is a source preview for supported Claude, Codex, and Devin runtimes. It includes workspace file tools, an isolated Linux command runner, customizable panes, and a separate application API. Provider support and execution boundaries are explicit; it is not a replacement for every feature of the original provider tools.

Project site · Getting started · Compare tools · Source · Application API · Compatibility reference · Contributing

Readiness

xcb is not yet a daily-driver replacement for Codex, Claude Code, and Devin. The native broker lists, reads, searches, and writes workspace files, creates directories, and removes or renames regular files with revision checks. The source also includes an isolated Linux command runner for tests and builds on macOS ARM64. The current backend passed its 12-case VM boundary suite, including filtered Git inspection, public dependency fetching, and offline Cargo/Bun use from immutable caches. Installed Claude and Codex coding workflows passed on macOS ARM64: an expected test failure, exact repair, passing test, and filtered Git status, with joined processes and settled effects. This evidence covers the tested accounts and admitted builds; Devin quota still blocks acceptance across all three providers. See the command runner contract for setup, supported boundaries, and current limits.

A successful doctor or a visible model does not prove a working coding session. Native doctor reports metadata pin only for unqualified providers. Codex and Devin candidates require the checked executable digest as well as the version; other builds and their Linux execution paths remain unavailable. Automated fixtures check boundaries; they do not establish authentication, service reliability, or real-model task quality. The TypeScript compatibility CLI's Codex and Devin task routes remain unqualified and disabled.

Native xcb

The source build is the current installation path. As of September 19, 2026, GitHub's latest published release is AgentMixer v0.3.0, with an AgentMixer package archive. No native xcb release or @hraness/xcb npm package is published. Source version 0.4.0 is not a published release. Check the release assets before downloading.

Install from source

Requires Git, the pinned Rust 1.97.1 toolchain, and platform build tools. Claude's supported execution boundary is macOS Seatbelt or Linux with a working, admitted bwrap configuration. The native Codex and Devin candidates currently require macOS Seatbelt; unsupported confinement fails closed.

git clone https://github.com/hraness/xcb.git
cd xcb
rustup toolchain install 1.97.1 --profile minimal
./scripts/install-native.sh
export PATH="$HOME/.local/bin:$PATH"
xcb --version
xcb --help

The installer builds with the lockfile and installs ~/.local/bin/xcb. XCB_INSTALL_PREFIX changes the prefix. Both the old TypeScript CLI and the native CLI use the name xcb; use command -v xcb to check which one is active.

First Claude session

Install an admitted Claude Code binary (major 2, version 2.1.268 or newer). xcb performs its own account sign-in below; it does not silently import your existing provider login.

xcb accounts add claude personal --plan Max
xcb doctor --provider claude
xcb accounts login personal
xcb accounts refresh personal
xcb models
xcb --cwd /absolute/path/to/your/project

--plan is a display label; it does not verify your subscription. Complete the browser sign-in when prompted. accounts refresh probes supported model and usage metadata. Unknown or stale usage percentages remain unknown. A proven Claude account-wide quota exhaustion stays blocked until its reported reset, even when its percentage has gone stale. The account list shows a retry estimate; see quota routing for the scope and credential binding. To select a model, copy its full observed key from xcb models and run xcb models default <key>.

If discovery finds the wrong binary, use xcb doctor --provider claude --executable /absolute/path/to/claude. The pin binds executable bytes and version. After upgrading xcb, restart open xcb terminals and rerun doctor. A process started from the old binary cannot adopt the replacement binary's pin, and older clients refuse new run records whose credential-custody format they do not understand. An account, metadata pin, or model listing cannot activate an unqualified adapter.

Connect Codex on macOS

Use the exact admitted 0.155.0-alpha.2.6 build. Authenticated broker read/write/read and installed coding-workflow acceptance passed on macOS ARM64 with the tested account; this does not qualify arbitrary provider versions or the separate application API. xcb supervises the official CLI's ChatGPT device sign-in in a private profile:

xcb doctor --provider codex
xcb accounts add codex codex-personal --plan ChatGPT
xcb accounts login codex-personal
xcb accounts refresh codex-personal
xcb models

Follow the device sign-in instructions shown in the terminal. Alternatively, copy one existing ChatGPT credential into a new xcb account by selecting its private auth.json explicitly:

xcb accounts import-codex --source /absolute/path/to/auth.json --label codex-imported
xcb accounts refresh codex-imported

The source file is preserved. Import does not copy provider configuration, plugins, sessions, or transcripts. API-key credentials are not accepted by this route. Refreshed ChatGPT credentials are persisted only after the owned provider process has joined.

Connect Devin on macOS

Use the exact admitted 3000.10.31 build. Authenticated ACP model discovery passed; the tested account returned quota/resource exhaustion on a real turn, so successful coding acceptance remains pending. xcb preserves an unknown quota reset as unknown. Sign in through the provider CLI, then explicitly select its credentials.toml to create a private xcb account:

devin auth login
xcb doctor --provider devin
xcb accounts import-devin --source /absolute/path/to/credentials.toml --label devin-personal
xcb accounts refresh devin-personal
xcb models

The source file and provider sessions are preserved. xcb copies only the credential for the supported provider endpoints. To update just the catalog, use xcb models refresh devin --account devin-personal; Devin discovery requires an explicitly connected account. Native Devin currently uses fixed ACP model choices. Adaptive and Fusion catalog representations in the compatibility package do not establish native support.

For either provider, copy a full matching model key from xcb models and set it with xcb models default <key>. Select the account with xcb accounts default <account> for new interactive sessions, or pass --account <account> --model <key> to xcb run. Rerun doctor after a provider upgrade; a new version is not automatically admitted.

Isolated tests, builds, and Git

Project commands use an explicitly provisioned Linux VM through workspace_exec. Follow the command runner setup from the same source checkout as the installed native CLI. Commands run offline against a staged workspace; host dependencies, credentials, and build products are excluded. Native macOS and Xcode builds are unavailable. The explicit public dependency preparation frontend passed the current VM boundary suite, including rejection of a cache after its manifest changed. Installed Claude and Codex coding workflows passed on macOS ARM64 with the tested accounts; other repositories and toolchains still need their own checks.

The Git projection is limited to filtered, read-only HEAD and index data for status and diffs. Original history, remotes, and hooks are omitted; commit and push workflows are unavailable. Publication checks file revisions and replaces each file atomically; it is not a transaction across every changed file. Failed, cancelled, or uncertain command state is retained. Successfully published and durably settled commands remove their verified input snapshot.

Application integration

The application API provides bounded, ephemeral inference with no tools or hooks. It requires evidence for the exact XCB binary, provider, account and model before accepting application traffic. TextButler, an MIT-licensed reference application, keeps its contact access and messaging approval in its own host. Sign-in and a successful doctor alone do not qualify the application route.

Everyday commands

xcb --cwd /absolute/path/to/your/project run --account personal -p "Explain this repository"
xcb sessions
xcb resume                 # latest native session
xcb resume <session-id>
xcb accounts
xcb config
xcb plugins
xcb panes
xcb doctor
xcb completions zsh > /path/to/completions/_xcb

Resume opens the saved native session and its workspace in the interactive terminal; it is not a headless continuation command. /help lists terminal commands. Sessions and credentials live in the private native state root ~/.local/share/xcb; --state /absolute/path or XCB_STATE overrides it. The compatibility CLI uses ~/.xcb instead. Do not point both implementations at the same state directory. xcb --json run includes the native session ID in its result so it can be reopened with xcb resume <session-id>.

One provider turn has a 30-minute default deadline, including initialization. The turn_timeout_ms setting in the private state root's config.json accepts 1,000–3,600,000 milliseconds (one second to 60 minutes); xcb config displays the effective configuration. Older configurations that omit it use the default. Cancellation remains available before the deadline, and automatic continuation has its own separate limits.

Each account owns at most one active provider turn. Other terminals may view that session, but cancellation must be requested in the terminal that owns it. Different accounts can run concurrently; the isolated command backend admits one command at a time across those accounts. Ctrl-C and SIGTERM request bounded cleanup for a headless run. xcb run reports success only for a completed, joined, settled idle result.

Cancellation joins the owned process before releasing custody. If doctor reports an unsettled run, inspect xcb recover and the process state; an expired lease or a quiet terminal is not proof that the provider stopped. Recovery is an explicit operation, not a reason to delete state or lock files.

Optional behavior

Auto-continue and Gobstopper context management default on with bounded continuation and settled-boundary checks. Disable either with xcb plugins disable auto-continue or xcb plugins disable gobstopper. Local usage measurement stays local. aiCharts upload is unavailable; local exports, external judgment, and executable hooks require separate opt-in. Panes are presentation data and cannot grant execution authority.

The optional judge uses TypeSafe System One (jev-latest) to advise routing, continuation, and context retention. It sends bounded task/response context to that service; old tool-result bodies are excluded from compaction advice. A judge cannot qualify a provider or bypass deterministic safety gates. Store a key through stdin on macOS or Linux, then explicitly enable it:

xcb judge token < /secure/path/to/judge-key
xcb judge status
xcb judge enable
xcb judge test
# Later:
xcb judge disable
xcb judge logout

The input file is an existing private credential file, not a command-line key. Keys are vaulted mode-0600 outside the workspace. XCB_JEV_API_KEY or TYPESAFE_API_KEY may supply a key via the environment. Custom endpoints require an explicit environment key; the vaulted key remains bound to System One.

Migrating from AgentMixer

The native command imports one Claude credential, preserving the source:

xcb accounts import-agentmixer --source /absolute/path/to/.agentmixer --label imported

It does not migrate transcripts or sessions. The compatibility source has its own migrate command and identifier changes; see the compatibility migration reference. Do not run compatibility migration commands against the native state root.

Standalone package

The retained TypeScript source provides host-owned routing, account custody, bounded tools, and provider adapters. It is separate from the native Rust app. For building it locally, library examples, qualification requirements, and its CLI commands, see the compatibility reference and managed Codex contract. The publishing contract describes future verified artifacts; it is not evidence of a published package.

Development

See Contributing for setup and the native, compatibility, and site checks. The credential-free native Codex boundary fixtures and native Devin boundary fixture document repeatable checks separately from authenticated live acceptance. Report vulnerabilities through Security. Licensed under MIT.