dumbridge

dumbridge gives a cloud coding agent temporary, live, read-only access to one local directory.

Install

No install step is needed. Run it with bunx dumbridge or npx --yes dumbridge. Bun 1.3.14 or newer must be on PATH.

Quickstart

On the computer that owns the files:

1. Start the bridge:

bunx dumbridge serve ~/projects/my-app

2. Copy the printed DUMBRIDGE_KEY value.
3. Put it in the cloud agent's environment as a secret. Do not log it or commit it.
4. Keep the serve process running. Ctrl-C stops it and revokes access.

In the cloud agent:

npx --yes dumbridge run 'ls -la'
npx --yes dumbridge pull src/config.json

run evaluates one script against the served root and prints its output. pull copies one file or directory from the served root into the current directory.

Commands

• dumbridge serve <root> serves one directory read-only and prints the bridge key. The key expires after 8 hours by default; set a different lifetime with --ttl '90 minutes'. --detach starts the server without a terminal, --stop ends a detached serve, and --status lists the active ones. --direct-only and --relay-only force the connection path.
• dumbridge run '<script>' evaluates one Bash-shaped script against the served root in a bounded sandbox. Writes are discarded. It never runs the host shell.
• dumbridge pull <remote-path> [destination] copies one file or directory from the served root. It verifies content, refuses symlinks, and never overwrites an existing destination.
• dumbridge doctor diagnoses the network environment without a key and exits non-zero when a check fails.
• dumbridge skill prints the bundled agent usage guide without contacting a bridge.

run and pull read the bridge key from DUMBRIDGE_KEY, or from --key-file <path> (- reads stdin). The key is never accepted as a command argument. Failures exit non-zero with a plain message that names the cause; --log-level debug on run or pull logs the dial sequence on stderr without exposing the key.

What it can and cannot do

• Read-only. The agent can read files below the served root. It cannot write to your machine.
• One directory. Only the directory you pass to serve is visible. Reads outside it are refused.
• No host shell. run uses a sandboxed interpreter, and its writes are discarded.
• Short-lived key. The bridge key is a bearer secret: anyone holding it can read the served root while serve runs. It expires on a deadline fixed when serve mints it, and stopping serve revokes it immediately.

Using it from a cloud agent

Put the DUMBRIDGE_KEY value in the agent's environment, then use run and pull as shown above. Proxy-jailed sandboxes work: the bundled iroh binding routes the relay connection through the environment's HTTP(S) proxy and can trust an extra CA certificate for TLS-intercepting proxies (DUMBRIDGE_CA_FILE, CODEX_PROXY_CERT, or SSL_CERT_FILE).

• Claude Code on the web: set Network access to Full.
• Codex Cloud: set the Domain allowlist to All (unrestricted).
• Cursor: works with no extra setup.

If a connection fails, run npx --yes dumbridge doctor in the agent to diagnose the environment.

License

MIT