franky-agent 0.0.4

Franky - a lean personal coding agent that builds in a hardened container and opens a PR.

Franky

A lean personal coding agent. Hand it a GitHub issue or a sentence, and it runs a coding agent inside a fresh, hardened Docker container that clones the repo, implements the change, and opens a pull request for you to review.

franky build https://github.com/you/repo/issues/42
franky build jira FOO-123 --repo you/repo
franky build "add a --json flag to the export command" --repo you/repo
franky build "fix the flaky retry test" --repo you/repo --engine claude

# Got review comments or red CI on a Franky PR? Iterate on it with follow-up commits.
franky iterate https://github.com/you/repo/pull/42

The agent is autonomous inside the container. The safety gate is four layers: a hardened container, a default-deny egress allowlist (the container reaches only your provider + GitHub + registries, via a creds-blind proxy), a fail-closed trusted-repo allowlist, and the fact that Franky opens a PR rather than merging - a human still reviews every change.

Why

Most coding-agent wrappers either lock you into one vendor or run the agent straight on your machine with your real credentials and shell. Franky does neither: the engine is pluggable, and the agent only ever runs inside a throwaway container with a narrowly scoped token.

Engines

Franky is vendor-neutral. The engine that runs inside the container is pluggable; all ship in the one image.

Engine	CLI	Auth	Notes
pi (default)	@earendil-works/pi-coding-agent	BYOK provider key	MIT, 15+ providers (OpenRouter, Anthropic, OpenAI, Ollama, ...)
claude	@anthropic-ai/claude-code	CLAUDE_CODE_OAUTH_TOKEN	Most capable; uses your Claude subscription
codex	@openai/codex	CODEX_API_KEY or OPENAI_API_KEY	OpenAI Codex headless (codex exec); API-key auth only

Select with --engine pi|claude|codex, or set FRANKY_ENGINE. Resolution order: --engine flag > FRANKY_ENGINE > default pi.

Install

Franky is published to PyPI as franky-agent (the installed command is franky):

uv tool install franky-agent
# or pipx:
pipx install franky-agent
# or:
pip install franky-agent

On first run the CLI pulls the version-pinned, public GHCR images (ghcr.io/vietlabs-work/franky:X.Y.Z and ghcr.io/vietlabs-work/franky-proxy:X.Y.Z), so all you need is Docker - no registry login. (Point FRANKY_GHCR_REPO at a different namespace if you host the images elsewhere.)

To move to a newer release later, run franky update - it detects how you installed (uv tool / pipx / pip) and reinstalls the latest version from PyPI via the same manager. franky update --force reinstalls even when already current. (A dev checkout updates via git; franky update is a no-op there.)

For local development, skip GHCR and point at local builds:

docker build -t franky .
docker build -t franky-proxy proxy/
export FRANKY_IMAGE=franky
export FRANKY_PROXY_IMAGE=franky-proxy

Franky is agent-agnostic to develop, not just to run: AGENTS.md is the canonical agent guide (build/test commands, architecture, the load-bearing invariants, how to add an engine), so Codex, Cursor, pi, or Claude Code all start with the same context. CLAUDE.md is a symlink to it.

Quickstart

1. Install Docker. Images are pulled automatically from GHCR on first run (see Install above). For local dev only, build them manually (see Install above).
2. Install Franky:

   python3 -m venv .venv && .venv/bin/pip install -e .
   

3. Configure credentials with the interactive wizard:

   franky config init
   

   This writes ~/.franky/config (mode 0600) and walks you through engine selection, FRANKY_ALLOWED_REPOS, GH_TOKEN, and engine creds. You can also set individual keys later:

   franky config set FRANKY_ALLOWED_REPOS
   franky config set GH_TOKEN          # secret - entered at a hidden prompt
   franky config list                  # view the file (secrets masked)
   franky config path                  # show where the file lives
   

   At minimum you need:
   • FRANKY_ALLOWED_REPOS - the trusted-repo allowlist (see below).
   • GH_TOKEN - scoped to contents + pull_requests on those repos.
   • the selected engine's creds (a provider key for pi, CLAUDE_CODE_OAUTH_TOKEN for claude, or CODEX_API_KEY / OPENAI_API_KEY for codex).
   • for JIRA tasks: JIRA_BASE_URL, JIRA_EMAIL, JIRA_API_TOKEN (host-side only, never forwarded into the container).
4. Run:

   franky build <gh-issue-url | jira KEY | "prose"> [--repo owner/repo] [--engine pi|claude|codex] [--plan-first]
   

Each run writes a redacted log to tasks/<timestamp>.log and prints the PR URL.

--plan-first adds an opt-in approval gate for sensitive targets: Franky runs a read-only planning pass, prints the plan, and waits for explicit confirmation before it builds or opens a PR. Decline (or run non-interactively) and nothing is written. The default stays autonomous - the sandbox plus PR review is the gate.

franky build also does a quick (~1s, cached) check for a newer release and prints a one-line hint if one exists - it never blocks the build. Silence it with FRANKY_NO_UPDATE_CHECK=1, or set FRANKY_AUTO_UPDATE=1 to auto-install the new release for your next run. (Both are host-CLI only; neither reaches the container.)

Iterating on a PR

Franky is no longer one-shot. When a PR it opened gets review comments or a red CI check, point it back at the PR and it responds with additive follow-up commits on the same branch:

franky iterate https://github.com/you/repo/pull/42 [--engine pi|claude|codex]

It runs the same hardened, egress-controlled container as franky build, but instead of starting fresh it checks out the PR's existing branch, reads the review comments and failing checks with gh (in-container, already allowlisted), addresses them, runs the tests green, and pushes. It never force-pushes, never rewrites history, never opens a new PR, and never merges - a human still reviews every change. The PR URL carries the repo, so there is no --repo flag, and the repo allowlist gates it exactly like build.

Unlike build (which prints the new PR URL to stdout), iterate opens no new PR - on a clean run it writes only an economics summary and a labeled completion line to stderr, and nothing to stdout. Review the existing PR for the new commits. The redacted transcript still lands in tasks/<timestamp>.log.

iterate is intended for Franky's own PRs. As a guardrail it is instructed to confirm the PR's head branch is a franky/* branch in the same repo (not a fork) before touching anything, and to stop otherwise. This is a prompt-level guard in the same register as the "never merge" rule (the agent is autonomous); the hard bounds remain the repo allowlist, the egress cage, and PR-not-merge. See the Security section.

Security

Read this before pointing Franky at anything.

Container hardening is load-bearing. Because the agent runs autonomously (claude with --dangerously-skip-permissions, codex with --dangerously-bypass-approvals-and-sandbox, pi with its default tools), the OS-level isolation is what bounds it, not tool-permission prompts. Franky runs the container with:

• --cap-drop=ALL, then adds back only CAP_SETUID/CAP_SETGID (needed by the rootless Docker daemon - see "Docker-in-Docker" below)
• --read-only root filesystem; writable paths only via --tmpfs (the clone, the agent's HOME, and the rootless Docker data root, each owned by the non-root uid)
• --pids-limit and --memory caps (with --memory-swap = --memory, no swap)
• a non-root user (uid 1001) baked into the image
• no Docker socket mount and no host bind mounts - the repo is cloned inside the container and the nested Docker daemon is rootless, so the agent never touches your filesystem or your host's Docker daemon
• only the selected engine's required env vars passed in; nothing else

Docker-in-Docker (always on)

Many repos cannot run their test suite without Docker (compose-based integration tests, testcontainers, a docker build step). So every Franky container runs its own rootless Docker daemon - the agent can docker build, docker compose up test infra, and run testcontainers entirely inside the sandbox. Nothing to enable; it is always available.

This is rootless DinD (a daemon running as the non-root franky user inside its own user namespace), not a mounted host Docker socket and not --privileged. It needs a few specific, minimal relaxations of the locked profile, applied to every task and verified on Docker Desktop for Mac:

• --security-opt=no-new-privileges is dropped (it blocks the setuid uid-map helpers rootless Docker needs to start),
• --security-opt=systempaths=unconfined (unmasks /proc so the nested runtime can mount it for inner containers - far narrower than --privileged/seccomp=unconfined),
• CAP_SETUID/CAP_SETGID added back on top of --cap-drop=ALL, and /dev/net/tun for the rootless network stack.

The blast radius stays bounded by everything else (rootless user namespace, read-only root, the egress cage below, no host FS, repo allowlist, PR-not-merge). The nested daemon's image pulls and docker build fetches go through the same egress proxy (it inherits HTTP(S)_PROXY), and inner containers have no route to the internet except that proxy - verified: an off-allowlist docker build FROM or RUN fetch is refused by the proxy, and a nested container's direct egress has no route out.

Egress control

The big v0 hole - a prompt-injected agent exfiltrating the creds it carries - is now closed by a default-deny egress allowlist. The task container runs on a Docker --internal network with NO route to the internet; its only peer is a Squid proxy enforcing a domain allowlist.

                  Docker --internal network (no internet route)
   +-----------------------------------------------------------------+
   |                                                                 |
   |   [ task container ] --HTTP(S)_PROXY--> [ franky-proxy (Squid) ]-+--> allowlisted
   |    --dns 127.0.0.1                       default-deny allowlist  |    hosts only
   |    (no creds on argv)                    (sees NO creds)         |
   +-----------------------------------------------------------------+

• Blind CONNECT, no creds at the proxy. Egress is HTTPS-only (port 443): Squid tunnels it with a blind CONNECT (no TLS termination), so it never sees the bytes - your Claude token or BYOK key tunnel through encrypted and are never visible to the proxy. Plain HTTP (port 80) is denied outright, so there is no cleartext, proxy-visible path even to an allowlisted host.
• DNS is killed in the task container (--dns 127.0.0.1), so a hostile agent cannot resolve or reach an off-allowlist host directly; only the proxy resolves.
• Fail-closed. Franky refuses to start the task unless the proxy is confirmed healthy, and the proxy refuses to start with an empty or malformed allowlist.
• The allowlist covers: your engine's provider host (e.g. api.anthropic.com, openrouter.ai, api.openai.com), GitHub (clone/push/PR), the npm + PyPI registries, and - because Docker-in-Docker is always on - a broad set of well-known container image registries (Docker Hub + CDN, GHCR, GCR/Artifact Registry, registry.k8s.io, Quay, ECR Public, MCR, GitLab, plus the CDNs they serve layer blobs from). Add extra hosts with FRANKY_EXTRA_ALLOWED_DOMAINS (comma-separated).

Residual risk. The allowlisted hosts are high-trust, but the agent can still reach GitHub, your model provider, the package registries, and the container registries above - so a determined injection could still smuggle data to one of those (e.g. a gist, an issue comment). Treat allowlisted destinations as trusted, not inert. Two consequences of always-on DinD specifically:

• Wider reachable set + a relaxed profile on every task (incl. non-Docker ones): the registry allowlist is broad (notably .cloudfront.net, a shared CDN), and the hardening relaxations above apply universally. This is a deliberate trade for "building/testing just works".
• The agent can move its own creds into nested containers (e.g. docker run -e GH_TOKEN ...). The egress allowlist still bounds where anything can go and PR-not-merge still bounds the damage, but the secret is no longer confined to a single process. There is also no per-inner-container resource limit and no cross-task concurrency cap - the outer --memory/--pids cap (~8 GB, tmpfs image storage is RAM) bounds one task's whole container tree.

v0 mitigations, still in force:

1. Fail-closed trusted-repo allowlist. Franky refuses any repo not in FRANKY_ALLOWED_REPOS, and refuses everything if that var is unset. This limits injection to content you already trust.

   The allowlist supports per-segment glob patterns (case-insensitive):

   • my-org/my-repo - exact match
   • my-org/* - every repo in my-org
   • my-org/team-* - repos with a name prefix
   • * - every repo the GH_TOKEN can reach (its full scope - a conscious opt-in, not the default; use only if the token is already narrowly scoped)

2. Scope your tokens narrowly. Give GH_TOKEN only contents + pull_requests on the target repos. Prefer a low-spend or separate API key for pi.

3. PR, not merge. Franky only opens PRs. You review before anything lands. franky iterate follows the same rule: it only pushes additive commits to an existing PR's branch (never force-push, never merge, never a new PR), and the "act only on a franky/* branch in the same repo" check is prompt-level - so point iterate only at PRs Franky itself opened, in an allowlisted repo.

GitHub Actions warning. Opening a PR can trigger workflows. A PR built from an attacker-influenced issue could run attacker-influenced workflow code with your repo's Actions secrets. Review workflow changes in the PR diff, and consider requiring approval for workflow runs on PRs.

Evals

Agent quality is probabilistic, so changes to the persona, prompt, model, or profile should be gated on a measured pass-rate, not a hunch. The eval harness runs a golden task set through the real Franky flow N times and reports pass-rate, plus a comparison mode that reports the delta between two configs (e.g. one engine vs another).

It is opt-in and out-of-band (like the manual egress check) - it needs real Docker + creds + a throwaway sandbox repo, so it is not part of the fast hermetic unit suite. Point evals/tasks.json at your sandbox repo and run:

make eval ARGS="-n 3 --engine pi --compare-engine codex"

See evals/README.md for setup, the task schema, and the success checkers.

Status

v0.0.4. Real end-to-end runs need live engine credentials, supplied out-of-band by the operator. The pieces under test here are the container hardening, the egress allowlist + proxy orchestration, the secret redaction, the trusted-repo allowlist, and the engine abstraction.