## Why
Rust falls back to `fork` when a macOS command combines a relative executable
path with a working directory, due to a historical `posix_spawnp` issue. This
can make local MCP server startup less reliable.
## What changed
- Spawn relative macOS MCP executables directly with `posix_spawn`, preserving
the configured path, `argv[0]`, working directory, environment, stdio, and
process group.
- Keep the existing launcher for `PATH` lookup and executable text files without
a shebang.
- Use one local child wrapper for legacy and 2026-07-28 protocol framing, with
cancellation-safe waiting and cleanup that kills and reaps dropped children.
## Testing
Add macOS regression coverage for relative scripts, argument and descriptor
preservation, launch errors, cancelled waits, and cleanup after runtime shutdown.
GitOrigin-RevId: 1cbc6b90aed6f67e0a38f551964d80496ebc4471
## What changed
- Update the Rust MCP SDK from `3.0.0-beta.3` to `3.0.0` and adapt to its renamed metadata and server discovery types.
- Accept discovery responses without server identity metadata, using the configured server name as a fallback, and rely on the SDK's native support for namespaced server identity metadata.
- Preserve typed OAuth HTTP errors so transport failures, cross-origin redirects, and transient HTTP responses are reported instead of being treated as anonymous access.
## Testing
- Cover modern discovery with namespaced or missing server identity over HTTP, SSE, and stdio.
- Cover OAuth discovery error propagation for transport failures, redirects, and transient status codes.
GitOrigin-RevId: 12c1e45136cca89ce4fb15986c2b5df14608682a
## What changed
- Drive multi-round `tools/call` and `resources/read` requests through
`input_required` responses, preserving opaque request state and elicitation
metadata across JSON, SSE, and stdio transports.
- Decode modern discovery and elicitation result shapes while retaining legacy
initialization, elicitation defaults, and discovery fallback behavior.
- Apply the 8 MiB modern-protocol response limit to JSON, SSE events, and stdio
messages, and reject executor stream recovery when output sequence gaps would
corrupt the protocol stream.
## Testing
Added integration coverage for discovery, multi-round requests, legacy
fallbacks, message limits, stdio launchers, SSE responses, session recovery,
and executor output recovery.
GitOrigin-RevId: d26a08883a2825e8ce2408ac498114b33859225e
Charlie Marsh