Browsing directories in the workspace picker or /cd starts a location runtime and its MCP servers for every directory listed #46826

Description

Every location-scoped fs endpoint runs through LocationMiddleware, so the
first read against a directory constructs the full location runtime
(config discovery, plugins, watchers) and starts one process set per MCP
server in that directory's config chain. Directory navigation uses those
endpoints.

Measured: opening the workspace picker on a directory with 68 subdirectories,
each inheriting two local MCP servers from the parent config, spawned 68
runtimes and 136 MCP processes (~21 GB RSS). Runtimes persist until the
location-activity sweep.

Plugins

None required; GET /api/fs/list?location[directory]=<abs> reproduces it on
its own.

OpenCode version

v2, local build from d57e210 (2026-09-02)

Steps to reproduce

1. Put a local MCP server in ~/workspace/.opencode/opencode.json.

2. In the TUI, type /cd ~/workspace/. Listing workspace's children
   materializes a runtime for ~/workspace itself and starts its MCP
   processes.

3. Type deeper: /cd ~/workspace/<subdir>/. That subdirectory gets its own
   runtime and a second set of the same MCP processes. Each deeper level the
   path reaches adds another.

4. The app picker does the same in bulk: opening it on ~/workspace creates
   one runtime and MCP process set per subdirectory immediately.

Screenshot and/or share link

Process table from the measured run can be attached if useful.

Operating System

Ubuntu 24.04 (Linux server)

Terminal

n/a (app + HTTP API)