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The local server.

The local server runs on your machine beside the desktop app. It serves MCP on the local socket and on the TCP and WebSocket listeners, and it runs the query client, the file manager and the response cache.

Figure 1Local server listenersspecified
LOCAL SERVERon your machineMCP serverquery clientresponse cachefile manageracquisition systemLOCAL SOCKETUnix socket or pipeSTDIO SHIMClaude Code and hostsTCP LISTENERloopback addressTERMINAL CLIENTa tool on the machineWEBSOCKET LISTENERloopback addressEXTENSION, SHELLSbrowser, desktop appNo listener accepts a connection from outside your machine. The app's session authenticates every listener.flows forwardthe result
The local server listens on the local socket, and on the TCP and WebSocket listeners when you turn them on. Each listener serves its own clients.Every listener stays on your machine.

The local server is the part of the platform that runs on your machine. It uses the same protocol as the platform’s own server, so a tool that works with one server works with the other.

Listeners#

listener address clients on by default
the local socket a Unix domain socket in the app’s support folder, or a named pipe on Windows the stdio shim and the desktop app yes
the TCP listener the loopback address of your machine a tool on the machine no, you turn it on in the app
the WebSocket listener the loopback address of your machine the browser extension and a tool on the machine no, you turn it on in the app

No listener accepts connections from outside your machine. The app’s own session authenticates every listener that you turn on.

Parts#

part function
the MCP server serves every tool of the platform, plus the app’s own tools for questions over your files, named procedures and the files themselves
the query client runs read-only queries over the lakehouse under your tenant’s credential, and calls the API for everything else
the file manager manages the workspace’s files and nothing outside the workspace
the response cache keeps recent results, so a question asked twice costs once
the acquisition system runs as a second process and takes in the pages that you read and the files that you drop

App tools#

tool function
si.ask.local runs a question, typed as one of the ask tools’ owning types, over the files that the app may read
si.work.local_procedure runs a named procedure on files in the workspace as a task, and records its steps in the app’s journal
the files tools download, upload and list files, and return the workspace

Claims#

claimstateroute or tool
The route /v1/ask/local runs a question over the app's own files.target/v1/ask/local
The route /v1/work/local_procedure runs a named procedure on the app.target/v1/work/local_procedure