restricted networking for all sandboxing methods, new seatbelt profiles, updated docs, fixes to sandbox build, debugging through sandbox (#891)

1 files changed, 5 insertions, 1 deletions

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e8aef8aa..5c67a0ea 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -215,7 +215,7 @@ To debug the CLI's React-based UI, you can use React DevTools. Ink, the library
 
 ### MacOS Seatbelt
 
-On MacOS, `gemini` uses Seatbelt (`sandbox-exec`) under a `minimal` profile (see `packages/cli/src/utils/sandbox-macos-minimal.sb`) that restricts writes to the project folder but otherwise allows all other operations by default. You can switch to a `strict` profile (see `.../sandbox-macos-strict.sb`) that declines operations by default by setting `SEATBELT_PROFILE=strict` in your environment or `.env` file. You can also switch to a custom profile `SEATBELT_PROFILE=<profile>` if you also create a file `.gemini/sandbox-macos-<profile>.sb` under your project settings directory `.gemini`.
+On MacOS, `gemini` uses Seatbelt (`sandbox-exec`) under a `permissive-open` profile (see `packages/cli/src/utils/sandbox-macos-permissive-open.sb`) that restricts writes to the project folder but otherwise allows all other operations and outbound network traffic ("open") by default. You can switch to a `restrictive-closed` profile (see `.../sandbox-macos-strict.sb`) that declines all operations and outbound network traffic ("closed") by default by setting `SEATBELT_PROFILE=restrictive-closed` in your environment or `.env` file. Available built-in profiles are `{permissive,restrictive}-{open,closed,proxied}` (see below for proxied networking). You can also switch to a custom profile `SEATBELT_PROFILE=<profile>` if you also create a file `.gemini/sandbox-macos-<profile>.sb` under your project settings directory `.gemini`.
 
 ### Container-based Sandboxing (All Platforms)
 
@@ -223,6 +223,10 @@ For stronger container-based sandboxing on MacOS or other platforms, you can set
 
 Container-based sandboxing mounts the project directory (and system temp directory) with read-write access and is started/stopped/removed automatically as you start/stop Gemini CLI. Files created within the sandbox should be automatically mapped to your user/group on host machine. You can easily specify additional mounts, ports, or environment variables by setting `SANDBOX_{MOUNTS,PORTS,ENV}` as needed. You can also fully customize the sandbox for your projects by creating the files `.gemini/sandbox.Dockerfile` and/or `.gemini/sandbox.bashrc` under your project settings directory (`.gemini`) and running `gemini` with `BUILD_SANDBOX=1` to trigger building of your custom sandbox.
 
+#### Proxied Networking
+
+All sandboxing methods, including MacOS Seatbelt using `*-proxied` profiles, support restricting outbound network traffic through a custom proxy server that can be specified as `GEMINI_SANDBOX_PROXY_COMMAND=<command>`, where `<command>` must start a proxy server that listens on `0.0.0.0:8877` for relevant requests. See `scripts/example-proxy.js` for a minimal proxy that only allows `HTTPS` connections to `example.com:443` (e.g. `curl https://example.com`) and declines all other requests. The proxy is started and stopped automatically alongside the sandbox.
+
 ## Manual Publish
 
 We publish an artifact for each commit to our internal registry. But if you need to manually cut a local build, then run the following commands: