Module proxy 

ai-crew-sync mcp proxy: a local stdio MCP server that forwards every tool call to the remote bus as one agent in one session.

Why a proxy at all: the bus is stateless Streamable HTTP and any MCP client can talk to it directly. What a direct connection cannot do is give each conversation its own session when several windows open the same repository with the same token — a header set once in a client config is the same header in every window. A stdio server is started by the host once per conversation (that is the MCP norm, and what Claude Code and Codex do), so the process itself is the unit of isolation: it mints the session label, sends it on every forwarded request, and keeps the project/role metadata for exactly that window.

The proxy is host-agnostic. What a host provides is used as an enrichment, never required:

• Conversation identity, in order: --host-session / BUS_HOST_SESSION (any host that can set per-window environment), CLAUDE_CODE_SESSION_ID (Claude Code exports it to MCP server processes; trusted only once the client names itself claude-code, because hosts started from a Claude Code terminal inherit it), ANTIGRAVITY_CONVERSATION_ID (where an Antigravity surface exports it to MCP servers), the conversation id a request carries in _meta (antigravity.google/conversation_id from Antigravity, threadId from Codex), and otherwise the process itself — a random id that lives as long as this instance. A known conversation id derives a stable session label, so a resumed conversation reconnects to the same session and a forked one gets a new one.
• Start-of-session context goes into the initialize result’s instructions, which every MCP client hands to the model. No hook needed.
• Presence is kept by the proxy itself: a heartbeat on connect (with repo and branch read from the project directory), a periodic keep-alive, idle on exit.

Two local tools, configure_session and session_status, never reach the remote server’s catalogue. They change metadata (project, role, channel) and, within the same team, the profile; a team change needs a new conversation, because switching credentials cannot erase what this conversation has already seen. Every profile change is verified with whoami before it is committed, in-flight calls to the old context are cancelled rather than replayed, and claims or locks held by the old identity are reported, never transferred.

Stdout carries MCP framing only; everything else goes to stderr.

Re-exports

pub use crate::context::session_for_host as session_for;

Structs

ConfigureArgs

ConfigureResult

EmptyArgs

PreviousIdentity

Proxy

ProxyOptions

Command-line shape of the proxy.

SessionProof

The credential this window proved itself with, when the bus issues them.

Status

Enums

Binding

Where the conversation id came from, reported by session_status.

Constants

ANTIGRAVITY_META_KEY

The _meta key under which Antigravity names the conversation on every tools/call.

CONFIGURE_TOOL

SESSION_PREFIX

Prefix of a session label the proxy mints. Opaque on purpose: the label is an address, project/role are the human-facing part.

STATUS_TOOL

Functions

run

Run the proxy over stdio until the host closes the pipe.