Files and directories

`~/.browspark/`

Path	Written by	Contents
`token`	companion, first start	Pairing token, mode `0600`. Delete to rotate.
`tools.json`	companion, when the dashboard changes the policy	`{"disabled": ["browser_upload", …]}`. Loaded on start so disabled tools stay disabled before the extension reconnects.
`profile/`	Chrome	Persistent profile of the `default` developer context.
`profiles/<name>/`	Chrome	Profiles of named developer contexts. `browser_session delete` removes one.
`downloads/<context>/`	Chrome	Downloads made in a developer context.
`artifacts/`	companion	Exports, see below.

Files are named by kind and id. Formats are Chrome’s own so each opens in DevTools or the usual tools.

Kind	Extension	Opens in
Performance trace	`.json`	DevTools Performance panel, Perfetto UI
CPU profile	`.cpuprofile`	DevTools Performance / JavaScript Profiler
Heap snapshot	`.heapsnapshot`	DevTools Memory panel
Allocation sampling	`.heapprofile`	DevTools Memory panel
Network export	`.har`	DevTools Network, HAR viewers
Lighthouse	`.html`, `.json`	Browser, Lighthouse viewer
Recorder flow	`.json`	`devtools_recorder`
Playwright export	`.spec.ts`	Playwright
PDF	`.pdf`	Any viewer

Tools that accept path write there as well as, or instead of, the artifacts directory (the tool page says which).

Storage	Keys	Lifetime
`chrome.storage.local`	`token`, `port`, `shareAll`, `stopped`, `activityLog`, `devMode`, `disabledTools`, `toolCatalog`, `idleDetachMs`	Persistent per browser profile
`chrome.storage.session`	`shared` (tab ids shared individually)	Until the browser restarts
`localStorage` of the dashboard page	theme, last selected setup client, expanded rows	Persistent, UI conveniences only

The activity log itself is held in the service worker’s memory only.

Folder	Contents
`companion/src/`	MCP server: `index.ts` (transports, relay, HTTP), `bridge.ts` (WebSocket and HTTP routes), `session.ts` (tab routing, contexts), `cdp.ts` (developer browsers), `page.ts` (snapshots, input, reading), `tools.ts` (browser tools), `live.ts`, `artifacts.ts`, `context.ts` (tool wrapper, policy, per-agent state), `devtools/` (one module per DevTools panel)
`companion/test/`	Unit tests, e2e scenarios, the harness, the capability and docs generators
`extension/`	`manifest.json`, `app.html`, `app.css`, `assets/`, `src/background.ts` (service worker), `src/app.ts` (dashboard), `src/state.ts`
`shared/`	`protocol.ts`, the wire protocol
`test-apps/`	Deterministic pages, API, service worker and source-mapped script used by the tests
`docs/`	This site