dsh-flutter-tools

A Flutter panel for the DeepSeek Harness sidebar: run, inspect and profile a Flutter app without leaving the conversation.

Devices come from a long-lived flutter daemon, launching is flutter run --machine with the VM Service URI picked up automatically, and everything else goes through the running app's own VM Service and flutter-devtools-mcp.

Features

• Devices — a long-lived flutter daemon (events, not polling): a phone plugged in appears by itself. The section shows one selected device with its OS logo (Apple, Android, Windows, Linux, or a browser for web targets) plus a small kind icon; clicking opens the list to switch, and the choice is remembered per project. Emulators come from the same daemon.
• Launch — device, mode (debug / profile / release), flavor and --dart-define pairs, then one button that runs or stops depending on the state. The panel reads app.debugPort and connects itself; app logs land in the panel.
• Flavor and defines — flavors are suggested from the project (Android productFlavors, non-default Xcode schemes); defines are a key/value editor. Both are remembered per project and validated before they reach the command line.
• Control — hot reload, hot restart, screenshot (inline), widget tree, debug paint.
• Debug toggles — the service extensions the app actually registered: debugPaint, showPerformanceOverlay, repaintRainbow, debugPaintBaselinesEnabled, timeDilation, inspector.show.
• DevTools inside the panel — the daemon hosts the DevTools server and the panel embeds it (inspector, performance, cpu-profiler, memory, network, logging), with a button to move the same page into a sidebar browser tab.
• App facts and memory — VM version, platform, pid and isolates as a key/value block; live heap readout, a GC button, saved memory snapshots and a compare of the last two.
• Captures and profiling — rebuild tracking and HTTP capture as single switches, profiling session, collect_performance_session with the workspace root filled in.
• Project commands — pub get, pub outdated, flutter doctor with rendered output: pub outdated becomes a table with the upgradable rows highlighted, flutter doctor a checklist.
• Detach and web — leave the app running while the panel stops tracking it, or open a web build in a sidebar browser tab.
• SDK — the workspace's own pin (.fvm/flutter_sdk, then .fvmrc) wins over whatever is on PATH.

Install

DeepSeek Harness → Settings → Add plugin, then paste this repository's address. That field takes a plugin package name, a GitHub repository address or a local directory. The CLI takes the same spec (dsh plugin add …); note that a profile the desktop app manages refuses CLI changes, so the plugin manager is the usual route.

Requirements:

• a Flutter SDK (the workspace pin is preferred, PATH is the fallback);
• npx on PATH — flutter-devtools-mcp is fetched on first use;
• dsh-better-sidebar for the sidebar tab;
• a Flutter app running in debug (rebuild tracking) or profile (metrics).

How it is put together

File	Half	Role
index.js	host (Cordis)	registers the /flutter routes, owns the flutter daemon, the flutter run child and the flutter-devtools-mcp child, serves panel.html
panel.html	served page	the whole UI, plain HTML/CSS/JS — no build step
client.js	client bundle	registers the sidebar tab whose body is an iframe onto /flutter
icon.svg	manifest asset	the icon the plugin manager shows, declared as icon in package.json
cordis.patch.yml	bundle patch	the mount row; its name must equal the package name so the client bundle is served at /plugins/dsh-flutter-tools/client.js
dev-server.mjs	development	runs the same routes outside DSH for UI iteration
docs/	development	the screenshots above

Endpoints

All under /flutter, loopback Host only.

Route	Purpose
GET /flutter	the panel page (?cwd=&sessionId=)
GET /flutter/config	workspace cwd, fvm pin, resolved Flutter, toggle labels
GET /flutter/devices	live device list (daemon)
GET /flutter/emulators	emulators from the daemon
GET /flutter/flavors	flavors found in the project (Android blocks + Xcode schemes)
GET /flutter/run	launch state: running, appId, mode, flavor, defines, VM Service URI, log tail
POST /flutter/run	launch on a device: { deviceId, mode, flavor, defines }
POST /flutter/run/stop	stop the launched app
POST /flutter/run/detach	leave the app running, stop tracking it
POST /flutter/emulator/launch	boot an emulator: { emulatorId }
GET /flutter/devtools	DevTools page URL: ?page=…&uri=
GET /flutter/extensions	registered debug extensions plus their current state
POST /flutter/extension	toggle one extension: { name, value } (allowlist only)
GET /flutter/heap	heap usage of the main isolate (?uri=)
POST /flutter/gc	collect garbage, then report heap usage
POST /flutter/command	one-shot CLI: pub_get | pub_outdated | doctor
POST /flutter/call	flutter-devtools-mcp tool call: { tool, arguments } (allowlist only)

Notes from building it

Things that cost time, recorded so nobody pays twice.

• flutter daemon --machine is not a valid flag: it exits 2 with no output. The daemon speaks the same protocol without it.
• flutter emulators --machine does not exist either.
• --show-web-server-device is deliberately not passed: measured, it changes exactly one thing — the synthetic web-server device appears in the list — and nothing here depends on it.
• flutter run, flutter daemon and npx are wrappers: the real process is a grandchild (dartvm), so a plain child.kill() leaves it running. Children are spawned detached and killed by process group — except after app.detach, where a group kill would take the detached app down with it, so the tool is killed by pid instead.
• Measured: the tool does not exit by itself after app.detach (still alive 20 s later), while the app it launched survives on its own.
• The VM Service needs an isolateId for getMemoryUsage, and has no collectAllGarbage RPC — that is what getAllocationProfile(gc: true) is for.
• ext.flutter.brightnessOverride is not offered as a toggle: it reports the platform's effective brightness, so "off" still reads as dark on a dark system and the switch would lie.
• --dart-define is compile-time: a changed define takes effect on the next launch, not on a hot restart.
• Command output is clipped head-first: pub outdated keeps its column header at the top, and a tail clip left the panel with rows it could not parse.
• The plugin icon is a data URL built by the harness from a top-level icon in package.json; there is no HTTP route for it, and the path must stay inside the manifest directory.

License

MIT — see LICENSE.

Development

node dev-server.mjs 9100 /path/to/flutter/project   # the panel, outside DSH

Screenshots in docs/ were taken from that dev server with Chrome in dark mode at device scale 2.

Attribution

The tab icon and the plugin icon are Flutter's mark, taken from simple-icons (CC0). Flutter is a trademark of Google; the mark is used here only to label Flutter tooling.