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External access (MCP / REST)

External MCP/REST access is the one switch that lets something outside the analyser drive it: Claude Code, Codex or another MCP client in your terminal, or a script. It is off by default, it is this user's setting on this machine, and nothing else in the analyser opens a port for outside callers.

Claude Code running inside the analyser does not need it: that session has its own private bridge (Claude Code in the analyser).

What it opens

When the switch is on, the analyser listens on 127.0.0.1 only, so nothing on the network can reach it:

  • on a port chosen afresh at each launch;
  • guarded by a token minted afresh at each launch, which every request must carry;
  • refusing any request that carries an Origin header, so a web page in your browser cannot drive it;
  • rate-limited to 10 calls a second, after a burst of 10.

It serves two routes: GET /manifest (the verbs and their schemas) and POST /action (one verb call). An MCP client reaches it through the analyser's own bridge, which you register once (Connect your client); a script calls it directly (Scripts and CI over REST).

What an outside client can then do is the same verbs a person has, under the same switches: file exchange, project creation (Security model ▸ What an assistant can do).

Turn it on, and off

Turning it on asks first, from every door below, with Cancel as the default; turning it off is one click and never asks.

  • AI ▸ External MCP/REST access, a checkbox; or
  • Settings ▸ Assistant ▸ Every assistant ▸ External MCP/REST access (for an AI client on this machine), the same setting; or
  • AI ▸ Set up AI… ▸ Your own AI client, whose Let programs on this computer reach this window switch is the same setting (and the Connect an AI client dialog behind its More options…, which offers Turn on External MCP/REST access… when it is off); or
  • start the analyser with --rest (analyser --rest, or java -jar fluxtion-auditlog-analyser.jar --rest). This turns the switch on and keeps it on: the setting persists, so later launches without the flag still have it on. Turn it off in Settings or the AI menu.

The status bar says External MCP/REST access is on: listening on http://127.0.0.1:… for external clients — …, and the light beside it reads MCP ready. The console prints the URL and only the token's first 8 characters; the full token is never printed.

A shared settings file cannot turn it on

This switch is set on each machine only. It is never exported, never applied on import and never in a project profile or an evidence bundle. A file that carries it anyway has it ignored, and the import summary says "External MCP/REST access is set on this machine only — this file's value was ignored" (Projects, profiles and sharing). To turn it on for a team, each person ticks it once on their own machine.

The endpoint file

While the switch is on, the analyser writes ~/.fluxtion-analyser/rest-endpoint, mode 600 (readable only by you):

{"url":"http://127.0.0.1:52041","token":"…","pid":12684,"startedAt":"2026-10-17T09:31:04Z"}
  • The MCP bridge reads it on every call, so a client's registration holds no port and no token.
  • A script reads it every time and checks that pid is a live process: a crashed analyser can leave a stale file.
  • The analyser removes it when its window closes or it quits normally.
  • No file means no access: the analyser is not running, the switch is off, or access is closed for a Claude Code session (below).

Anything running as you can read this file, and so can drive the analyser while the switch is on. That includes your own Claude Code with full permissions, in a terminal or inside the analyser.

Which window serves

One analyser window at a time owns the endpoint file. The analyser started last takes it; a window takes it back only when the live owner closes. The light in each window's status bar says which: MCP ready (this window serves) or MCP elsewhere (another window does). Troubleshooting ▸ Which window is serving has every state.

Closing it for one Claude Code session

With Full Claude Code running in the analyser and the switch on, the session's own tools could read the endpoint file and drive the analyser as an outside client, including the destructive verbs. So the panel offers Close external access while this session runs.

When the person at the analyser chooses it, the endpoint file is withdrawn and outside clients are refused until that session ends, although Settings still shows the switch on; the light reads MCP starting. It opens again by itself when the session ends. What a client and a script are told meanwhile is quoted on Troubleshooting ▸ While Claude Code runs in the analyser.

With the switch off, Claude Code in the analyser still works through its private listener, which refuses every outside client, even one holding an old token, and publishes no endpoint file.

Who can change it

Every user can turn the switch on for themselves; there is no administrator lock yet (Managed policy). The token is minted per launch and never stored anywhere else, and Copy prompt includes it only when you tick Include my local REST token, which starts unticked each time.