- introduces `ClientResponse` as the symmetrical typed response union to
`ClientRequest` for app-server-protocol
- enables scalable event stream ingestion for use cases such as
analytics
- no runtime behavior changes, protocol/schema plumbing only
## Why
`codex-tools` already owns the shared tool input schema model and parser
from the first extraction step, but `core/src/tools/spec.rs` still owned
the MCP-specific adapter that normalizes `rmcp::model::Tool` schemas and
wraps `structuredContent` into the call result output schema.
Keeping that adapter in `codex-core` means the reusable MCP schema path
is still split across crates, and the unit tests for that logic stay
anchored in `codex-core` even though the runtime orchestration does not
need to move yet.
This change takes the next small step by moving the reusable MCP schema
adapter into `codex-tools` while leaving `ResponsesApiTool` assembly in
`codex-core`.
## What changed
- added `tools/src/mcp_tool.rs` and sibling
`tools/src/mcp_tool_tests.rs`
- introduced `ParsedMcpTool`, `parse_mcp_tool()`, and
`mcp_call_tool_result_output_schema()` in `codex-tools`
- updated `core/src/tools/spec.rs` to consume parsed MCP tool parts from
`codex-tools`
- removed the now-redundant MCP schema unit tests from
`core/src/tools/spec_tests.rs`
- expanded `codex-rs/tools/README.md` to describe this second migration
step
## Test plan
- `cargo test -p codex-tools`
- `cargo test -p codex-core --lib tools::spec::`
## Summary
This PR makes Windows sandbox proxying enforceable by routing proxy-only
runs through the existing `offline` sandbox user and reserving direct
network access for the existing `online` sandbox user.
In brief:
- if a Windows sandbox run should be proxy-enforced, we run it as the
`offline` user
- the `offline` user gets firewall rules that block direct outbound
traffic and only permit the configured localhost proxy path
- if a Windows sandbox run should have true direct network access, we
run it as the `online` user
- no new sandbox identity is introduced
This brings Windows in line with the intended model: proxy use is not
just env-based, it is backed by OS-level egress controls. Windows
already has two sandbox identities:
- `offline`: intended to have no direct network egress
- `online`: intended to have full network access
This PR makes proxy-enforced runs use that model directly.
### Proxy-enforced runs
When proxy enforcement is active:
- the run is assigned to the `offline` identity
- setup extracts the loopback proxy ports from the sandbox env
- Windows setup programs firewall rules for the `offline` user that:
- block all non-loopback outbound traffic
- block loopback UDP
- block loopback TCP except for the configured proxy ports
- optionally allow broader localhost access when `allow_local_binding=1`
So the sandboxed process can only talk to the local proxy. It cannot
open direct outbound sockets or do local UDP-based DNS on its own.The
proxy then performs the real outbound network access outside that
restricted sandbox identity.
### Direct-network runs
When proxy enforcement is not active and full network access is allowed:
- the run is assigned to the `online` identity
- no proxy-only firewall restrictions are applied
- the process gets normal direct network access
### Unelevated vs elevated
The restricted-token / unelevated path cannot enforce per-identity
firewall policy by itself.
So for Windows proxy-enforced runs, we transparently use the logon-user
sandbox path under the hood, even if the caller started from the
unelevated mode. That keeps enforcement real instead of best-effort.
---------
Co-authored-by: Codex <noreply@openai.com>
Michael Bolin