agent_wires_mcp 0.1.7

MCP server that bridges an LLM agent to a running Flutter app via the Dart VM service. Pairs with agent_wires_probe.

Changelog

0.1.7

• Fix Windows startup crash. ProcessSignal.sigterm.watch() throws SignalException on Windows (Failed to listen for SIGTERM ... errno = 50), killing the MCP server before it could serve. The SIGTERM shutdown listener is now guarded with !Platform.isWindows; SIGINT still handles Ctrl+C / client shutdown on Windows. Thanks @mwothman (#15).
• Pairs with agent_wires_probe 0.1.9 (recommendedProbeVersion bumped) — picks up the probe's scroll (#12) and screenshot (#13) reliability fixes.

0.1.6

Adds the action overlay narration layer (pairs with agent_wires_probe 0.1.7). Tool count grows 24 → 25.

• New set_action_overlay(enabled) tool toggles the probe's on-screen overlay — the ripples/highlights/flashes drawn where the agent taps, types, points, and looks. It is for a human watching the device and never appears in screenshot/snapshot. On by default.
• label_element now flashes a point-at highlight on the named element (via the probe) so a watcher sees what was labelled.
• recommendedProbeVersion tracks agent_wires_probe 0.1.7.

0.1.5

Boot reliability fix.

Fail fast when flutter run dies during boot

• boot_app no longer hangs for the full timeout when the build fails. FlutterRunner.start awaited the VM-service URI (up to 10 min) but never watched the flutter process itself. If flutter run --machine spawned, printed progress ("Running Xcode build..."), then exited without emitting a recognised failure event — a codesign/build failure, no matching device, or flutter resolving to the wrong SDK (e.g. an fvm-managed Flutter not on the spawned PATH) — the boot wedged on the timeout while app_status showed a frozen progress line and no flutter/xcodebuild process was even alive. start now also watches exitCode and fails the boot immediately when flutter exits early, attaching a tail of flutter's stderr and the likely causes so the agent gets an actionable error in seconds instead of a multi-minute hang.

0.1.4

Docs-only release. No code changes — refreshes the README to match the 0.1.3 tool surface and behaviour so the pub.dev page is accurate.

• Removes the -d device pin from the MCP config examples (it contradicted the "don't pin at registration" guidance and is the phone-vs-simulator stall trap); the agent picks a device at session time via list_devices + boot_app.
• Corrects the tool count to 24.
• Documents that screenshot returns {path, …} by default (base64 via return_base64: true).
• recommendedProbeVersion tracks agent_wires_probe 0.1.6.

0.1.3

Connection- and lifecycle-hardening from a real LLM-agent driving session (physical iPhone, then simulator) where a dropped VM-service connection cascaded into multi-minute hangs and leaked processes. No tool additions; app_status gains probe_version / probe_version_warning / paused_at_start fields, and hot_reload / hot_restart failures gain recoverable + hint.

Fail-fast instead of hanging on a dead connection

• Per-call timeout + connection-lost latch. When the device VM-service connection dropped (Service connection disposed, JSON-RPC -32603), every ext.qa.* call used to block on the dead socket until cancelled — boot_app ran 601s, get_logs 633s, even stop_app 219s. VmClient now bounds each call and latches a lost-connection state the instant the socket closes, a call returns disposed, or a call times out; subsequent calls and isProbeAlive fail immediately with a clear "reattach or reboot" error. A dead connection is distinguished from a stale isolate, so it no longer triggers a rebind that would re-hang.
• Teardown never blocks on the VM-service. stop_app bounds VM-service disposal so it always tears down the OS process, even when the connection is already dead.

Reap the whole flutter process tree

• No more orphaned flutter run / DDS / devicectl / iproxy. stop_app (and server exit on SIGINT/SIGTERM) now snapshots the descendant process tree before killing flutter — children reparent to launchd the moment flutter dies — then SIGTERM→SIGKILL the lot. Stops the per-cycle leak that left multiple servers/runs contending for the same device and VM-service.

Resume a paused-at-start launch

• Frozen --start-stopped apps now run. A physical iPhone launched via devicectl … --start-stopped boots with main() paused; nothing resumed it, so the app sat frozen while app_status read ready. Attach now resumes any paused-at-start isolate before locating the QA isolate (a paused isolate hasn't registered the probe yet). When a resume can't be confirmed, app_status reports paused_at_start: true instead of a misleading healthy status.

Hot reload/restart — recover from DevFS wedges

• Retry-then-explain on DevFS synchronization failed. hot_reload / hot_restart retry once (the failure is often transient); if it still fails, the result carries recoverable: false and a hint to run stop_app + boot_app, instead of a bare success: false.

Smaller robustness wins

• boot_app(device_id) switches devices without a deadlock. A device switch on a running session force-stops it (process-level) instead of rejecting with "call stop_app first" — which used to deadlock when the VM-service was already dead.
• Probe/server version-skew warning. The probe reports its version over ext.qa.ping; app_status surfaces probe_version and warns when it differs from the version this server pairs with (0.1.5).
• get_logs can't blow the client token budget. Oversized message / error / stack fields are truncated (default 4000 chars each, with a dropped-char marker) so a single ~110k-char Flutter stack no longer overruns the MCP client limit. Pagination is preserved.

0.1.2

Hot-restart robustness from real LLM-agent driving sessions. No tool additions; app_status gains a probe_attached field.

Self-healing isolate binding

• Recovers from hot restart automatically. A hot restart collects the QA isolate and starts a new one. The client used to keep calling the dead isolate id, so every ext.qa.* call failed with [Sentinel kind: Collected] for the rest of the session and never recovered. callExtension now re-resolves the live ext.qa.* isolate and retries once on a stale-isolate error, so a single tool call recovers transparently.
• app_status reports probe_attached. Distinct from state, which only tracks the flutter run process: after a hot restart the process stays up (state stays ready) but the probe moves to a fresh isolate. state:"ready" with probe_attached:false now tells the agent the probe is reattaching, instead of looking healthy while every call fails. The check re-resolves and rebinds when the bound isolate has been collected.
• Clearer error when the probe is truly gone. If re-resolution fails (the app exited, or hot-restarted without AgentWiresProbe.install()), the agent gets an actionable message instead of the raw VM-service sentinel string.

0.1.1

Post-0.1.0 iteration driven by real LLM-agent driving sessions. Tool count grows from 18 → 23 (5 new lifecycle tools). Several tool input schemas gain optional flags; nothing existing breaks.

New: lifecycle tools

• list_devices — runs flutter devices --machine and returns a curated [{id, name, platform, is_emulator, is_supported, sdk}, ...] list. Agent calls this when multiple devices might be connected (the classic 10-min-hang trigger: phone + sim, flutter picks the phone and stalls on signing).
• boot_app / app_status / stop_app — explicit lifecycle instead of "boot happens magically on first tool call." boot_app accepts device_id (pick the device per session), wait (false for fire-and-forget so the agent can poll progress). Sticks the device choice until the next stop_app.
• hot_reload — re-injects edited Dart sources, preserves state + current route. Lazy mode uses flutter run --machine's app.restart (true Flutter reload with reassemble); attached mode falls back to VM-service reloadSources (sources swap, no reassemble).
• hot_restart — tears down the isolate and re-runs main(). State lost. Only supported in lazy mode (where we own the flutter subprocess). Attached mode returns a clear "use your own restart" error.

Boot: visible instead of black box

• Lazy boot. agent_wires_mcp run no longer blocks on flutter run --machine before opening MCP stdio. The handshake returns in milliseconds; flutter only starts when the agent calls boot_app (or any other tool, via auto-boot). Previously Claude Code's 30s connection timeout killed every cold-cache session.
• Progress streaming. Each app.progress and non-error daemon.logMessage event from flutter is captured on the session, surfaced in app_status.latest_progress, and written to MCP-server stderr so Claude Code's MCP log viewer also shows it. A long Xcode build / pod install now reads as "Running Xcode build..." in app_status instead of a silent 5-minute wait.
• Fail-fast on launch errors. app.stop with an error payload, or any error-level daemon log, immediately fails the boot future with that message. No more 10-minute timeouts on "No supported devices connected."
• Recovery. Lazy sessions in exited reset to idle on the next ensureReady; the agent can retry boot_app after a timeout or stop_app without reconstructing the MCP server. Attached sessions stay terminal (we don't own that flutter process).
• Default boot timeout 5 min → 10 min — large apps with firebase / syncfusion / flutter_quill routinely run past 5 on a cold compile.

Perception tools — smaller, more accurate

• snapshot gains include_unresolved: false by default. The unresolved array (the worst noise: 10–25k chars of unlabelled Listeners, decorative Switches, FAB carriers) is hidden; the count is reported as unresolved_count instead. Agents that need to drive a hidden widget (pin-code fields) opt in explicitly.
• screenshot writes the PNG to a tmp file and returns {path, width, height, size_bytes} by default — was 329k chars of inline base64 that the agent couldn't actually read. The old behavior is available via return_base64: true.
• inspect gains include_descendants (default true) and descendant_depth (default 3) — returns a subtree view with painter + size exposed for CustomPaint descendants. Lets the agent answer "what's inside this Card?" or "is this region drawn pixels?" in one call.

Sync — diagnose what's keeping the app awake

• wait_for_idle returns a structured payload on timeout: {idle, blocked_by, in_flight_http, has_scheduled_frame, in_transient_callback}. The agent now knows whether to wait longer, retry, or proceed.
• New ignore_animations flag — drops the frame/animation checks, waits only for HTTP. Use on screens with continuous spring animations that never visually settle.

Tool descriptions

• All 23 tool descriptions rewritten to disambiguate (snapshot vs. screenshot, the three wait_for_* siblings) and teach the canonical agent loop. The biggest behavioral change: agents now reach for snapshot first by default; screenshot correctly signals "almost always prefer snapshot."

Internal

• AppSession introduced as the lifecycle hub; runner + VM client state lives there with explicit state machine (idle, booting, ready, exited).
• FlutterRunner captures the appId from app.started, routes machine-protocol responses to per-request completers, exposes a general-purpose progress callback.
• DeviceLister wraps flutter devices --machine; parser tolerates leading log lines.

0.1.0

Initial public release.

• 18 MCP tools across five categories: perception (snapshot, inspect, screenshot), action (tap, long_press, swipe, enter_text, clear_text, scroll, press_back), sync (wait_for_idle, wait_for_route, wait_for_element), observability (get_logs, get_network), and memory (label_element, get_labels, recall).
• agent_wires_mcp run — boots flutter run --machine, auto-discovers the VM service URI, and serves MCP over stdio in one process. Forwards --flavor, -t/--target, --dart-define.
• agent_wires_mcp serve --attach <ws-uri> — attaches to an already- running app.
• agent_wires_mcp review — local human-curation dashboard at localhost:7345 for labelling unresolved widgets. Per-project persistence in .flutter_qa/map.json.
• Snapshot enrichment — merges human labels and source-location proposals (via the analyzer package) before returning to the agent.
• Set-of-Mark mode — screenshot(annotated: true) overlays numbered boxes for vision-augmented agents.
• Requires the target app to have agent_wires_probe installed.