Commit Graph

1727 Commits

  • Update cargo to 2024 edition (#842)
    Some effects of this change:
    - New formatting changes across many files. No functionality changes
    should occur from that.
    - Calls to `set_env` are considered unsafe, since this only happens in
    tests we wrap them in `unsafe` blocks
  • chore: introduce codex-common crate (#843)
    I started this PR because I wanted to share the `format_duration()`
    utility function in `codex-rs/exec/src/event_processor.rs` with the TUI.
    The question was: where to put it?
    
    `core` should have as few dependencies as possible, so moving it there
    would introduce a dependency on `chrono`, which seemed undesirable.
    `core` already had this `cli` feature to deal with a similar situation
    around sharing common utility functions, so I decided to:
    
    * make `core` feature-free
    * introduce `common`
    * `common` can have as many "special interest" features as it needs,
    each of which can declare their own deps
    * the first two features of common are `cli` and `elapsed`
    
    In practice, this meant updating a number of `Cargo.toml` files,
    replacing this line:
    
    ```toml
    codex-core = { path = "../core", features = ["cli"] }
    ```
    
    with these:
    
    ```toml
    codex-core = { path = "../core" }
    codex-common = { path = "../common", features = ["cli"] }
    ```
    
    Moving `format_duration()` into its own file gave it some "breathing
    room" to add a unit test, so I had Codex generate some tests and new
    support for durations over 1 minute.
  • fix: make all fields of Session struct private again (#840)
    https://github.com/openai/codex/pull/829 noted it introduced a circular
    dep between `codex.rs` and `mcp_tool_call.rs`. This attempts to clean
    things up: the circular dep still exists, but at least all the fields of
    `Session` are private again.
  • feat: support mcp_servers in config.toml (#829)
    This adds initial support for MCP servers in the style of Claude Desktop
    and Cursor. Note this PR is the bare minimum to get things working end
    to end: all configured MCP servers are launched every time Codex is run,
    there is no recovery for MCP servers that crash, etc.
    
    (Also, I took some shortcuts to change some fields of `Session` to be
    `pub(crate)`, which also means there are circular deps between
    `codex.rs` and `mcp_tool_call.rs`, but I will clean that up in a
    subsequent PR.)
    
    `codex-rs/README.md` is updated as part of this PR to explain how to use
    this feature. There is a bit of plumbing to route the new settings from
    `Config` to the business logic in `codex.rs`. The most significant
    chunks for new code are in `mcp_connection_manager.rs` (which defines
    the `McpConnectionManager` struct) and `mcp_tool_call.rs`, which is
    responsible for tool calls.
    
    This PR also introduces new `McpToolCallBegin` and `McpToolCallEnd`
    event types to the protocol, but does not add any handlers for them.
    (See https://github.com/openai/codex/pull/836 for initial usage.)
    
    To test, I added the following to my `~/.codex/config.toml`:
    
    ```toml
    # Local build of https://github.com/hideya/mcp-server-weather-js
    [mcp_servers.weather]
    command = "/Users/mbolin/code/mcp-server-weather-js/dist/index.js"
    args = []
    ```
    
    And then I ran the following:
    
    ```
    codex-rs$ cargo run --bin codex exec 'what is the weather in san francisco'
    [2025-05-06T22:40:05] Task started: 1
    [2025-05-06T22:40:18] Agent message: Here’s the latest National Weather Service forecast for San Francisco (downtown, near 37.77° N, 122.42° W):
    
    This Afternoon (Tue):
    • Sunny, high near 69 °F
    • West-southwest wind around 12 mph
    
    Tonight:
    • Partly cloudy, low around 52 °F
    • SW wind 7–10 mph
    ...
    ```
    
    Note that Codex itself is not able to make network calls, so it would
    not normally be able to get live weather information like this. However,
    the weather MCP is [currently] not run under the Codex sandbox, so it is
    able to hit `api.weather.gov` and fetch current weather information.
    
    ---
    [//]: # (BEGIN SAPLING FOOTER)
    Stack created with [Sapling](https://sapling-scm.com). Best reviewed
    with [ReviewStack](https://reviewstack.dev/openai/codex/pull/829).
    * #836
    * __->__ #829
  • fix: build all crates individually as part of CI (#833)
    I discovered that `cargo build` worked for the entire workspace, but not
    for the `mcp-client` or `core` crates.
    
    * `mcp-client` failed to build because it underspecified the set of
    features it needed from `tokio`.
    * `core` failed to build because it was using a "feature" of its own
    crate in the default, no-feature version.
     
    This PR fixes the builds and adds a check in CI to defend against this
    sort of thing going forward.
  • fix: ensure apply_patch resolves relative paths against workdir or project cwd (#810)
    https://github.com/openai/codex/pull/800 kicked off some work to be more
    disciplined about honoring the `cwd` param passed in rather than
    assuming `std::env::current_dir()` as the `cwd`. As part of this, we
    need to ensure `apply_patch` calls honor the appropriate `cwd` as well,
    which is significant if the paths in the `apply_patch` arg are not
    absolute paths themselves. Failing that:
    
    - The `apply_patch` function call can contain an optional`workdir`
    param, so:
    - If specified and is an absolute path, it should be used to resolve
    relative paths
    - If specified and is a relative path, should be resolved against
    `Config.cwd` and then any relative paths will be resolved against the
    result
    - If `workdir` is not specified on the function call, relative paths
    should be resolved against `Config.cwd`
    
    Note that we had a similar issue in the TypeScript CLI that was fixed in
    https://github.com/openai/codex/pull/556.
    
    As part of the fix, this PR introduces `ApplyPatchAction` so clients can
    deal with that instead of the raw `HashMap<PathBuf,
    ApplyPatchFileChange>`. This enables us to enforce, by construction,
    that all paths contained in the `ApplyPatchAction` are absolute paths.
  • fix: is_inside_git_repo should take the directory as a param (#809)
    https://github.com/openai/codex/pull/800 made `cwd` a property of
    `Config` and made it so the `cwd` is not necessarily
    `std::env::current_dir()`. As such, `is_inside_git_repo()` should check
    `Config.cwd` rather than `std::env::current_dir()`.
    
    This PR updates `is_inside_git_repo()` to take `Config` instead of an
    arbitrary `PathBuf` to force the check to operate on a `Config` where
    `cwd` has been resolved to what the user specified.
  • feat: make cwd a required field of Config so we stop assuming std::env::current_dir() in a session (#800)
    In order to expose Codex via an MCP server, I realized that we should be
    taking `cwd` as a parameter rather than assuming
    `std::env::current_dir()` as the `cwd`. Specifically, the user may want
    to start a session in a directory other than the one where the MCP
    server has been started.
    
    This PR makes `cwd: PathBuf` a required field of `Session` and threads
    it all the way through, though I think there is still an issue with not
    honoring `workdir` for `apply_patch`, which is something we also had to
    fix in the TypeScript version: https://github.com/openai/codex/pull/556.
    
    This also adds `-C`/`--cd` to change the cwd via the command line.
    
    To test, I ran:
    
    ```
    cargo run --bin codex -- exec -C /tmp 'show the output of ls'
    ```
    
    and verified it showed the contents of my `/tmp` folder instead of
    `$PWD`.
  • feat: configurable notifications in the Rust CLI (#793)
    With this change, you can specify a program that will be executed to get
    notified about events generated by Codex. The notification info will be
    packaged as a JSON object. The supported notification types are defined
    by the `UserNotification` enum introduced in this PR. Initially, it
    contains only one variant, `AgentTurnComplete`:
    
    ```rust
    pub(crate) enum UserNotification {
        #[serde(rename_all = "kebab-case")]
        AgentTurnComplete {
            turn_id: String,
    
            /// Messages that the user sent to the agent to initiate the turn.
            input_messages: Vec<String>,
    
            /// The last message sent by the assistant in the turn.
            last_assistant_message: Option<String>,
        },
    }
    ```
    
    This is intended to support the common case when a "turn" ends, which
    often means it is now your chance to give Codex further instructions.
    
    For example, I have the following in my `~/.codex/config.toml`:
    
    ```toml
    notify = ["python3", "/Users/mbolin/.codex/notify.py"]
    ```
    
    I created my own custom notifier script that calls out to
    [terminal-notifier](https://github.com/julienXX/terminal-notifier) to
    show a desktop push notification on macOS. Contents of `notify.py`:
    
    ```python
    #!/usr/bin/env python3
    
    import json
    import subprocess
    import sys
    
    
    def main() -> int:
        if len(sys.argv) != 2:
            print("Usage: notify.py <NOTIFICATION_JSON>")
            return 1
    
        try:
            notification = json.loads(sys.argv[1])
        except json.JSONDecodeError:
            return 1
    
        match notification_type := notification.get("type"):
            case "agent-turn-complete":
                assistant_message = notification.get("last-assistant-message")
                if assistant_message:
                    title = f"Codex: {assistant_message}"
                else:
                    title = "Codex: Turn Complete!"
                input_messages = notification.get("input_messages", [])
                message = " ".join(input_messages)
                title += message
            case _:
                print(f"not sending a push notification for: {notification_type}")
                return 0
    
        subprocess.check_output(
            [
                "terminal-notifier",
                "-title",
                title,
                "-message",
                message,
                "-group",
                "codex",
                "-ignoreDnD",
                "-activate",
                "com.googlecode.iterm2",
            ]
        )
    
        return 0
    
    
    if __name__ == "__main__":
        sys.exit(main())
    ```
    
    For reference, here are related PRs that tried to add this functionality
    to the TypeScript version of the Codex CLI:
    
    * https://github.com/openai/codex/pull/160
    * https://github.com/openai/codex/pull/498
  • fix: overhaul SandboxPolicy and config loading in Rust (#732)
    Previous to this PR, `SandboxPolicy` was a bit difficult to work with:
    
    
    https://github.com/openai/codex/blob/237f8a11e11fdcc793a09e787e48215676d9b95b/codex-rs/core/src/protocol.rs#L98-L108
    
    Specifically:
    
    * It was an `enum` and therefore options were mutually exclusive as
    opposed to additive.
    * It defined things in terms of what the agent _could not_ do as opposed
    to what they _could_ do. This made things hard to support because we
    would prefer to build up a sandbox config by starting with something
    extremely restrictive and only granting permissions for things the user
    as explicitly allowed.
    
    This PR changes things substantially by redefining the policy in terms
    of two concepts:
    
    * A `SandboxPermission` enum that defines permissions that can be
    granted to the agent/sandbox.
    * A `SandboxPolicy` that internally stores a `Vec<SandboxPermission>`,
    but externally exposes a simpler API that can be used to configure
    Seatbelt/Landlock.
    
    Previous to this PR, we supported a `--sandbox` flag that effectively
    mapped to an enum value in `SandboxPolicy`. Though now that
    `SandboxPolicy` is a wrapper around `Vec<SandboxPermission>`, the single
    `--sandbox` flag no longer makes sense. While I could have turned it
    into a flag that the user can specify multiple times, I think the
    current values to use with such a flag are long and potentially messy,
    so for the moment, I have dropped support for `--sandbox` altogether and
    we can bring it back once we have figured out the naming thing.
    
    Since `--sandbox` is gone, users now have to specify `--full-auto` to
    get a sandbox that allows writes in `cwd`. Admittedly, there is no clean
    way to specify the equivalent of `--full-auto` in your `config.toml`
    right now, so we will have to revisit that, as well.
    
    Because `Config` presents a `SandboxPolicy` field and `SandboxPolicy`
    changed considerably, I had to overhaul how config loading works, as
    well. There are now two distinct concepts, `ConfigToml` and `Config`:
    
    * `ConfigToml` is the deserialization of `~/.codex/config.toml`. As one
    might expect, every field is `Optional` and it is `#[derive(Deserialize,
    Default)]`. Consistent use of `Optional` makes it clear what the user
    has specified explicitly.
    * `Config` is the "normalized config" and is produced by merging
    `ConfigToml` with `ConfigOverrides`. Where `ConfigToml` contains a raw
    `Option<Vec<SandboxPermission>>`, `Config` presents only the final
    `SandboxPolicy`.
    
    The changes to `core/src/exec.rs` and `core/src/linux.rs` merit extra
    special attention to ensure we are faithfully mapping the
    `SandboxPolicy` to the Seatbelt and Landlock configs, respectively.
    
    Also, take note that `core/src/seatbelt_readonly_policy.sbpl` has been
    renamed to `codex-rs/core/src/seatbelt_base_policy.sbpl` and that
    `(allow file-read*)` has been removed from the `.sbpl` file as now this
    is added to the policy in `core/src/exec.rs` when
    `sandbox_policy.has_full_disk_read_access()` is `true`.
  • fix: eliminate runtime dependency on patch(1) for apply_patch (#718)
    When processing an `apply_patch` tool call, we were already computing
    the new file content in order to compute the unified diff. Before this
    PR, we were shelling out to `patch(1)` to apply the unified diff once
    the user accepted the change, but this updates the code to just retain
    the new file content and use it to write the file when the user accepts.
    This simplifies deployment because it no longer assumes `patch(1)` is on
    the host.
    
    Note this change is internal to the Codex agent and does not affect
    `protocol.rs`.
  • feat: add debug landlock subcommand comparable to debug seatbelt (#715)
    This PR adds a `debug landlock` subcommand to the Codex CLI for testing
    how Codex would execute a command using the specified sandbox policy.
    
    Built and ran this code in the `rust:latest` Docker container. In the
    container, hitting the network with vanilla `curl` succeeds:
    
    ```
    $ curl google.com
    <HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
    <TITLE>301 Moved</TITLE></HEAD><BODY>
    <H1>301 Moved</H1>
    The document has moved
    <A HREF="http://www.google.com/">here</A>.
    </BODY></HTML>
    ```
    
    whereas this fails, as expected:
    
    ```
    $ cargo run -- debug landlock -s network-restricted -- curl google.com
    curl: (6) getaddrinfo() thread failed to start
    ```
  • feat: make it possible to set disable_response_storage = true in config.toml (#714)
    https://github.com/openai/codex/pull/642 introduced support for the
    `--disable-response-storage` flag, but if you are a ZDR customer, it is
    tedious to set this every time, so this PR makes it possible to set this
    once in `config.toml` and be done with it.
    
    Incidentally, this tidies things up such that now `init_codex()` takes
    only one parameter: `Config`.
  • fix: tighten up check for /usr/bin/sandbox-exec (#710)
    * In both TypeScript and Rust, we now invoke `/usr/bin/sandbox-exec`
    explicitly rather than whatever `sandbox-exec` happens to be on the
    `PATH`.
    * Changed `isSandboxExecAvailable` to use `access()` rather than
    `command -v` so that:
      *  We only do the check once over the lifetime of the Codex process.
      * The check is specific to `/usr/bin/sandbox-exec`.
    * We now do a syscall rather than incur the overhead of spawning a
    process, dealing with timeouts, etc.
    
    I think there is still room for improvement here where we should move
    the `isSandboxExecAvailable` check earlier in the CLI, ideally right
    after we do arg parsing to verify that we can provide the Seatbelt
    sandbox if that is what the user has requested.
  • fix: increase timeout of test_writable_root (#713)
    Although we made some promising fixes in
    https://github.com/openai/codex/pull/662, we are still seeing some
    flakiness in `test_writable_root()`. If this continues to flake with the
    more generous timeout, we should try something other than simply
    increasing the timeout.
  • feat: load defaults into Config and introduce ConfigOverrides (#677)
    This changes how instantiating `Config` works and also adds
    `approval_policy` and `sandbox_policy` as fields. The idea is:
    
    * All fields of `Config` have appropriate default values.
    * `Config` is initially loaded from `~/.codex/config.toml`, so values in
    `config.toml` will override those defaults.
    * Clients must instantiate `Config` via
    `Config::load_with_overrides(ConfigOverrides)` where `ConfigOverrides`
    has optional overrides that are expected to be settable based on CLI
    flags.
    
    The `Config` should be defined early in the program and then passed
    down. Now functions like `init_codex()` take fewer individual parameters
    because they can just take a `Config`.
    
    Also, `Config::load()` used to fail silently if `~/.codex/config.toml`
    had a parse error and fell back to the default config. This seemed
    really bad because it wasn't clear why the values in my `config.toml`
    weren't getting picked up. I changed things so that
    `load_with_overrides()` returns `Result<Config>` and verified that the
    various CLIs print a reasonable error if `config.toml` is malformed.
    
    Finally, I also updated the TUI to show which **sandbox** value is being
    used, as we do for other key values like **model** and **approval**.
    This was also a reminder that the various values of `--sandbox` are
    honored on Linux but not macOS today, so I added some TODOs about fixing
    that.
  • fix: write logs to ~/.codex/log instead of /tmp (#669)
    Previously, the Rust TUI was writing log files to `/tmp`, which is
    world-readable and not available on Windows, so that isn't great.
    
    This PR tries to clean things up by adding a function that provides the
    path to the "Codex config dir," e.g., `~/.codex` (though I suppose we
    could support `$CODEX_HOME` to override this?) and then defines other
    paths in terms of the result of `codex_dir()`.
    
    For example, `log_dir()` returns the folder where log files should be
    written which is defined in terms of `codex_dir()`. I updated the TUI to
    use this function. On UNIX, we even go so far as to `chmod 600` the log
    file by default, though as noted in a comment, it's a bit tedious to do
    the equivalent on Windows, so we just let that go for now.
    
    This also changes the default logging level to `info` for `codex_core`
    and `codex_tui` when `RUST_LOG` is not specified. I'm not really sure if
    we should use a more verbose default (it may be helpful when debugging
    user issues), though if so, we should probably also set up log rotation?
  • fix: small fixes so Codex compiles on Windows (#673)
    Small fixes required:
    
    * `ExitStatusExt` differs because UNIX expects exit code to be `i32`
    whereas Windows does `u32`
    * Marking a file "executable only by owner" is a bit more involved on
    Windows. We just do something approximate for now (and add a TODO) to
    get things compiling.
    
    I created this PR on my personal Windows machine and `cargo test` and
    `cargo clippy` succeed. Once this is in, I'll rebase
    https://github.com/openai/codex/pull/665 on top so Windows stays fixed!
  • fix: remove dependency on expanduser crate (#667)
    In putting up https://github.com/openai/codex/pull/665, I discovered
    that the `expanduser` crate does not compile on Windows. Looking into
    it, we do not seem to need it because we were only using it with a value
    that was passed in via a command-line flag, so the shell expands `~` for
    us before we see it, anyway. (I changed the type in `Cli` from `String`
    to `PathBuf`, to boot.)
    
    If we do need this sort of functionality in the future,
    https://docs.rs/shellexpand/latest/shellexpand/fn.tilde.html seems
    promising.
  • fix: flipped the sense of Prompt.store in #642 (#663)
    I got the sense of this wrong in
    https://github.com/openai/codex/pull/642. In that PR, I made
    `--disable-response-storage` work, but broke the default case.
    
    With this fix, both cases work and I think the code is a bit cleaner.
  • [codex-rs] Improve linux sandbox timeouts (#662)
    * Fixes flaking rust unit test
    * Adds explicit sandbox exec timeout handling
  • feat: add ZDR support to Rust implementation (#642)
    This adds support for the `--disable-response-storage` flag across our
    multiple Rust CLIs to support customers who have opted into Zero-Data
    Retention (ZDR). The analogous changes to the TypeScript CLI were:
    
    * https://github.com/openai/codex/pull/481
    * https://github.com/openai/codex/pull/543
    
    For a client using ZDR, `previous_response_id` will never be available,
    so the `input` field of an API request must include the full transcript
    of the conversation thus far. As such, this PR changes the type of
    `Prompt.input` from `Vec<ResponseInputItem>` to `Vec<ResponseItem>`.
    
    Practically speaking, `ResponseItem` was effectively a "superset" of
    `ResponseInputItem` already. The main difference for us is that
    `ResponseItem` includes the `FunctionCall` variant that we have to
    include as part of the conversation history in the ZDR case.
    
    Another key change in this PR is modifying `try_run_turn()` so that it
    returns the `Vec<ResponseItem>` for the turn in addition to the
    `Vec<ResponseInputItem>` produced by `try_run_turn()`. This is because
    the caller of `run_turn()` needs to record the `Vec<ResponseItem>` when
    ZDR is enabled.
    
    To that end, this PR introduces `ZdrTranscript` (and adds
    `zdr_transcript: Option<ZdrTranscript>` to `struct State` in `codex.rs`)
    to take responsibility for maintaining the conversation transcript in
    the ZDR case.
  • [codex-rs] Reliability pass on networking (#658)
    We currently see a behavior that looks like this:
    ```
    2025-04-25T16:52:24.552789Z  WARN codex_core::codex: stream disconnected - retrying turn (1/10 in 232ms)...
    codex> event: BackgroundEvent { message: "stream error: stream disconnected before completion: Transport error: error decoding response body; retrying 1/10 in 232ms…" }
    2025-04-25T16:52:54.789885Z  WARN codex_core::codex: stream disconnected - retrying turn (2/10 in 418ms)...
    codex> event: BackgroundEvent { message: "stream error: stream disconnected before completion: Transport error: error decoding response body; retrying 2/10 in 418ms…" }
    ```
    
    This PR contains a few different fixes that attempt to resolve/improve
    this:
    1. **Remove overall client timeout.** I think
    [this](https://github.com/openai/codex/pull/658/files#diff-c39945d3c42f29b506ff54b7fa2be0795b06d7ad97f1bf33956f60e3c6f19c19L173)
    is perhaps the big fix -- it looks to me like this was actually timing
    out even if events were still coming through, and that was causing a
    disconnect right in the middle of a healthy stream.
    2. **Cap response sizes.** We were frequently sending MUCH larger
    responses than the upstream typescript `codex`, and that was definitely
    not helping. [Fix
    here](https://github.com/openai/codex/pull/658/files#diff-d792bef59aa3ee8cb0cbad8b176dbfefe451c227ac89919da7c3e536a9d6cdc0R21-R26)
    for that one.
    3. **Much higher idle timeout.** Our idle timeout value was much lower
    than typescript.
    4. **Sub-linear backoff.** We were much too aggressively backing off,
    [this](https://github.com/openai/codex/pull/658/files#diff-5d5959b95c6239e6188516da5c6b7eb78154cd9cfedfb9f753d30a7b6d6b8b06R30-R33)
    makes it sub-exponential but maintains the jitter and such.
    
    I was seeing that `stream error: stream disconnected` behavior
    constantly, and anecdotally I can no longer reproduce. It feels much
    snappier.
  • [codex-rs] More fine-grained sandbox flag support on Linux (#632)
    ##### What/Why
    This PR makes it so that in Linux we actually respect the different
    types of `--sandbox` flag, such that users can apply network and
    filesystem restrictions in combination (currently the only supported
    behavior), or just pick one or the other.
    
    We should add similar support for OSX in a future PR.
    
    ##### Testing
    From Linux devbox, updated tests to use more specific flags:
    ```
    test linux::tests_linux::sandbox_blocks_ping ... ok
    test linux::tests_linux::sandbox_blocks_getent ... ok
    test linux::tests_linux::test_root_read ... ok
    test linux::tests_linux::test_dev_null_write ... ok
    test linux::tests_linux::sandbox_blocks_dev_tcp_redirection ... ok
    test linux::tests_linux::sandbox_blocks_ssh ... ok
    test linux::tests_linux::test_writable_root ... ok
    test linux::tests_linux::sandbox_blocks_curl ... ok
    test linux::tests_linux::sandbox_blocks_wget ... ok
    test linux::tests_linux::sandbox_blocks_nc ... ok
    test linux::tests_linux::test_root_write - should panic ... ok
    ```
    
    ##### Todo
    - [ ] Add negative tests (e.g. confirm you can hit the network if you
    configure filesystem only restrictions)
  • feat: initial import of Rust implementation of Codex CLI in codex-rs/ (#629)
    As stated in `codex-rs/README.md`:
    
    Today, Codex CLI is written in TypeScript and requires Node.js 22+ to
    run it. For a number of users, this runtime requirement inhibits
    adoption: they would be better served by a standalone executable. As
    maintainers, we want Codex to run efficiently in a wide range of
    environments with minimal overhead. We also want to take advantage of
    operating system-specific APIs to provide better sandboxing, where
    possible.
    
    To that end, we are moving forward with a Rust implementation of Codex
    CLI contained in this folder, which has the following benefits:
    
    - The CLI compiles to small, standalone, platform-specific binaries.
    - Can make direct, native calls to
    [seccomp](https://man7.org/linux/man-pages/man2/seccomp.2.html) and
    [landlock](https://man7.org/linux/man-pages/man7/landlock.7.html) in
    order to support sandboxing on Linux.
    - No runtime garbage collection, resulting in lower memory consumption
    and better, more predictable performance.
    
    Currently, the Rust implementation is materially behind the TypeScript
    implementation in functionality, so continue to use the TypeScript
    implmentation for the time being. We will publish native executables via
    GitHub Releases as soon as we feel the Rust version is usable.