Merge pull request 'feat(gui): explain Run Diagnostic + offer to launch the game — 0.13.0' (#8) from feat/m6-steam-detection into main

Reviewed-on: #8

CHANGELOG.md

@@ -5,6 +5,70 @@ All notable changes to RigDoctor are recorded here. Format follows
 (`MAJOR.MINOR.PATCH`, pre-1.0). `__version__` and `pyproject.toml` must match the git
 release tag (so the auto-updater, D18, can compare versions).
 
+## [0.13.0] - 2026-05-22
+### Added
+- **Run Diagnostic now explains itself and can launch the game.** Clicking Run Diagnostic shows
+  what to do — *play the game, reproduce the crash, then Finish & analyze* (and that data
+  survives a hard freeze + reboot) — and offers **Launch game & start** (asks Steam to run it by
+  appid) or **Start without launching**. The recording banner now spells out the next step
+  instead of just showing a sample count.
+### Fixed
+- Button labels containing "&" (e.g. "Finish & analyze") rendered as "Finish _analyze" because
+  Qt treated the "&" as a keyboard mnemonic — now escaped so the ampersand shows literally.
+
+## [0.12.0] - 2026-05-22
+### Added
+- **Guided diagnostic in the GUI.** Each game on the **Games** page now has a **Run Diagnostic**
+  button → a focused, game-tagged capture starts and a recording banner appears (live sample
+  count, GPU-lost indicator) with **Finish & analyze** / **Discard**. Finishing opens a results
+  dialog: the window-scoped capture summary (peak temps/power, events, last samples) plus the
+  health findings as cards. The banner persists/restores if you navigate away and back while a
+  capture is running. Shares `core/diagnostic.py` with the CLI (one flow, three front-ends).
+
+## [0.11.0] - 2026-05-22
+### Added
+- **Guided diagnostic session (CLI) — the seed use case, end to end.** `rigdoctor diagnose
+  start --game "<name>"` runs a **focused crash-capture tagged with that game** (its own
+  diagnostic log, so the report is scoped to just that session), `diagnose status` shows
+  progress, and `diagnose finish` stops it and prints a combined report: the **capture
+  summary** (peak temps/power, GPU-lost events, last samples — M3) plus the **health findings**
+  (Xid/SMART/driver/etc. — M4). The game can be given by `--game` or `--appid` (resolved from
+  the Steam scan), and is recorded as a log event so it survives a crash + reboot.
+- Shared orchestration lives in `core/diagnostic.py` (one callable for CLI/GUI/tray, per
+  ARCHITECTURE §7.1); the recorder/`record run` gained an optional `--game` tag.
+
+## [0.10.2] - 2026-05-22
+### Changed
+- When an Environment **Apply**/**Install** fails, the status now shows the **real reason**
+  (cancelled at the password prompt vs. the system rejecting the change, e.g. a BIOS/kernel-
+  locked PCIe ASPM policy) instead of a vague "cancelled, or needs privileges".
+
+## [0.10.1] - 2026-05-22
+### Fixed
+- **Environment-page contrast.** The combo-box **drop-down list** was rendering light-on-light
+  (the popup view is a separate widget the theme didn't cover) — now dark with readable text.
+- The **Install / Apply** buttons on findings were hard to read (the accent fill didn't paint
+  reliably inside the finding cards, leaving dim dark-on-dark text). They're now an outlined
+  style — bright accent text on the dark card, filling accent on hover — readable regardless,
+  and given a minimum height so the row can't crush them.
+
+## [0.10.0] - 2026-05-22
+### Added
+- **Actionable Environment page (M6) — install & apply, not just advice.** Findings that
+  recommend a tool or a setting are now one-click:
+  - **Install buttons** for GameMode, MangoHud, and cpupower (added to the M9 component catalog,
+    so they also appear on the **Setup** page with the existing installer).
+  - **Apply controls** for runtime-reversible tunables — a dropdown of the live options + Apply,
+    via a single pkexec prompt, no reboot: **CPU governor**, **NVIDIA persistence mode**,
+    **PCIe ASPM policy**, **vm.swappiness**, **Transparent HugePages** (`core/fixes.py`). The
+    chosen value is validated against the live options before anything runs.
+  - This is the consent-gated apply milestone D9 anticipated, scoped to safe settings (**D22**).
+    GRUB-based fixes and CPU mitigations stay suggestion-only; `rigdoctor gameenv` still prints
+    the exact commands for headless use.
+### Changed
+- The `Finding` model gained optional `action` (installable component) and `fix` (applyable
+  tunable) fields; the shared `finding_card` widget renders the matching control.
+
 ## [0.9.0] - 2026-05-22
 ### Added
 - **Gaming environment checks (M6) — the evaluate-and-suggest engine.** A new read-only report

docs/DECISIONS.md

@@ -223,9 +223,25 @@ The next version is **determined by the Conventional Commit types** since the la
 `packaging/bump.sh` writes it into `__init__.py` + `pyproject.toml`. Rules live in
 `cliff.toml [bump]` (pre-1.0: `breaking_always_bump_major = false`).
 
+### D22 — Limited live apply of fixes (M6) — *DECIDED 2026-05-22; realizes the D9 milestone*
+D9 deferred auto-applying fixes to "a deliberate later milestone, gated behind explicit user
+consent." That milestone lands here, **scoped tightly to stay safe**:
+- **Only runtime-reversible settings** are applyable from the gaming-environment report (M6):
+  **CPU governor, NVIDIA persistence mode, PCIe ASPM policy, vm.swappiness, Transparent
+  HugePages.** Each takes effect immediately, needs **no reboot**, and reverts on reboot.
+- **How:** a dropdown of the live options + an Apply button per finding (`core/fixes.py`).
+  Applying runs a **single pkexec-elevated command** (one auth prompt); the chosen value is
+  validated against the live options first; writes target **sysfs/procfs or `nvidia-smi`** —
+  never the GRUB cmdline or a persistent config file.
+- **Still suggestion-only** (the read-only stance holds for these): GRUB-based `pcie_aspm=off`,
+  CPU **mitigations** changes (security-sensitive, need a reboot), and the shader-cache env var.
+- Everything remains **CLI-discoverable** (`rigdoctor gameenv` still prints the exact commands);
+  the apply UI is an additive convenience in the GUI, not the only path. Installing optional
+  tools (GameMode/MangoHud/cpupower) reuses the M9 installer and is likewise one-click.
+
 ## Open
 
-None currently — all tracked decisions (D1–D21) are resolved. New questions will be added
+None currently — all tracked decisions (D1–D22) are resolved. New questions will be added
 here as they arise. Remaining detail to flesh out during build: the tray's supporting-action
 set (D13), per-module apt package names, M12's tunnel/token specifics, and M13's
 update mechanism (APT repo vs. self-installed `.deb`).

docs/MODULES.md

@@ -51,9 +51,13 @@ Status: ⬜ not started · 🟦 designing · 🟨 in progress · ✅ done
   *Env-check engine implemented* (`core/gameenv.py`): a read-only findings report (reusing the
   M4 `Finding` model) over PCIe ASPM, NVIDIA persistence mode, CPU governor (the three seed-case
   contributors to GPU bus-drop / Xid 79), GameMode, MangoHud, swappiness, shader cache, THP, CPU
-  mitigations, and installed Proton versions — each with the suggested fix command (D9). CLI
+  mitigations, and installed Proton versions — each with the suggested fix command. CLI
-  `rigdoctor gameenv`; GUI **Environment** page. *Pending:* non-Steam launchers (Lutris/Heroic)
+  `rigdoctor gameenv`; GUI **Environment** page. Per **D22**, the GUI adds **one-click apply**
-  and per-GPU power-profile (PowerMizer) checks.
+  for the runtime-reversible tunables (governor / NVIDIA persistence / PCIe ASPM / swappiness /
+  THP — dropdown + Apply via a single pkexec prompt, `core/fixes.py`) and **one-click install**
+  of optional tools (GameMode / MangoHud / cpupower, now in the M9 catalog). GRUB/mitigations
+  stay suggestion-only. *Pending:* non-Steam launchers (Lutris/Heroic) and GPU power-profile
+  (PowerMizer) checks.
 - **M8 Alerting** — threshold/event notifications; integrates with the tray applet (M11).
 - **M10 Desktop GUI** — PySide6 graphical front-end over the core engine (dashboard, log
   browser, report viewer, logger controls). Optional; adds the Qt dependency. *Bootstrapped

docs/ROADMAP.md

@@ -40,8 +40,13 @@ Ubuntu + NVIDIA first; `.deb` distribution (see `DECISIONS.md`).
 - [ ] M10 desktop GUI (PySide6: dashboard, log browser, report viewer, logger controls)
 - [ ] M11 tray / menu-bar applet (QSystemTrayIcon: live M1 readouts + Run Diagnostic +
       supporting actions — D13)
-- [ ] Guided diagnostic session (pick game → focused M3 capture → M4 scan → findings),
+- [~] Guided diagnostic session (pick game → focused M3 capture → M4 scan → findings),
-      shared by tray/GUI/CLI
+      shared by tray/GUI/CLI — *core + CLI + GUI done* (`core/diagnostic.py`, `rigdoctor
+      diagnose start/status/finish`, and a **Run Diagnostic** button per game on the GUI Games
+      page → recording banner → results dialog with the capture summary + findings). Tags a
+      focused capture with the chosen game (own diagnostic log, window-scoped report) and
+      combines the capture summary with the M4 findings. *Pending:* the tray (M11) entry point,
+      and auto start/stop via the D12 wrapper/watcher.
 - [ ] Logger trigger modes: always-on + game-launch (D12 — wrapper first:
       `rigdoctor wrap %command%` + global Steam compat-tool; zero-config watcher
       (Steam RunningAppID + /proc) and GameMode hook follow)
@@ -57,8 +62,10 @@ Ubuntu + NVIDIA first; `.deb` distribution (see `DECISIONS.md`).
 - [x] M13 auto-update (D18) — launch-time version check (GUI sidebar) + no-root self-update
       apply (`rigdoctor update` / sidebar button → authenticated pip upgrade), token-gated.
       Restart-after-update is manual for now.
-- [ ] (Later, separate milestone) Optional auto-apply of suggested fixes behind explicit
+- [~] Optional auto-apply of suggested fixes behind explicit consent (D9 milestone) — *first
-      consent — currently out of scope (D9)
+      cut shipped for M6 (D22):* one-click apply of runtime-reversible tunables (CPU governor,
+      NVIDIA persistence, PCIe ASPM, swappiness, THP) via a single pkexec prompt, no reboot.
+      GRUB-based fixes + CPU mitigations remain suggestion-only.
 
 ## Phase 6 — Session sharing / remote assist  (M12, D16)
 Escalating ladder, built in order:

docs/SPEC.md

@@ -43,9 +43,12 @@ RigDoctor's crash-safe logger is designed to fix exactly that.
 - **Not a stress-test / load-generator** — explicitly out of scope (D7). Users can run
   existing tools (gpu-burn, vkmark, stress-ng) alongside the logger if they want.
 - Not an overclocking utility.
-- **Not (yet) an auto-fixer.** RigDoctor is **read-only**: it diagnoses and *suggests*
+- **Read-only by default, with a narrow consent-gated exception.** RigDoctor diagnoses and
-  actions (with the exact command where possible) but does not apply changes itself in this
+  *suggests* actions (with the exact command where possible). It does **not** apply changes
-  stage. Auto-apply is a deliberate later milestone behind explicit consent. (D9)
+  itself — **except** a small set of **runtime-reversible** gaming tunables (M6: CPU governor,
+  NVIDIA persistence, PCIe ASPM policy, swappiness, THP) that can be applied from the GUI via a
+  single pkexec prompt, no reboot, revert on reboot (D22, realizing the D9 milestone). Risky/
+  persistent fixes (GRUB cmdline, CPU mitigations) remain suggestion-only.
 
 ## 3. Target users & platforms
 
@@ -96,8 +99,10 @@ PCIe topology. Exportable (Markdown/JSON) to paste into forum/bug reports.
 ### M6 — Gaming environment checks
 Detects & evaluates: GPU power profile / persistence mode, CPU governor, Proton/Wine/Steam
 versions, GameMode, MangoHud, shader cache, swappiness, hugepages, CPU mitigations,
-PCIe ASPM. Flags settings that hurt stability/performance and **suggests** the fix command
+PCIe ASPM. Flags settings that hurt stability/performance and **suggests** the fix command.
-(read-only per D9).
+Also includes Steam library/game detection (the D12 "pick a game" foundation) and, per D22,
+a **one-click apply** for the runtime-reversible tunables (governor, persistence, ASPM,
+swappiness, THP) plus one-click install of optional tools (GameMode/MangoHud/cpupower).
 
 ### M8 — Alerting
 Threshold + event alerts (desktop notification / sound / log) on overheat, throttle,

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "rigdoctor"
-version = "0.9.0"
+version = "0.13.0"
 description = "Modular hardware monitoring & crash diagnostics for Linux gamers."
 readme = "README.md"
 requires-python = ">=3.11"

src/rigdoctor/__init__.py

@@ -1,3 +1,3 @@
 """RigDoctor — modular hardware monitoring & crash diagnostics for Linux gamers."""
 
-__version__ = "0.9.0"
+__version__ = "0.13.0"

src/rigdoctor/cli.py

@@ -86,6 +86,7 @@ def cmd_record_run(args) -> int:
         max_bytes=cfg["log_max_bytes"],
         backups=cfg["log_backups"],
         status_path=config.STATUS_FILE,
+        game=getattr(args, "game", None),
     )
 
     def _handle(_sig, _frame):
@@ -345,6 +346,77 @@ def cmd_report(args) -> int:
     return 0
 
 
+def _resolve_game(args) -> str | None:
+    """Game name from --game, or looked up from --appid via the Steam scan."""
+    if getattr(args, "game", None):
+        return args.game
+    if getattr(args, "appid", None):
+        from .core import steam
+
+        for g in steam.scan_games(steam.selected_library_paths()):
+            if g.appid == str(args.appid):
+                return g.name
+        return None
+    return None
+
+
+def cmd_diagnose(args) -> int:
+    from .core import diagnostic, reccontrol, steam
+
+    sub = args.diagnose_cmd or "status"
+
+    if sub == "start":
+        if reccontrol.running_pid():
+            print("A capture is already running — finish it with: rigdoctor diagnose finish")
+            return 1
+        game = _resolve_game(args)
+        if game is None and (args.game or args.appid):
+            print("Couldn't match that game in your selected Steam libraries.")
+            return 1
+        if game is None:
+            games = steam.cached_games() or steam.scan_games(steam.selected_library_paths())
+            if games:
+                print("Pick a game to focus on, then re-run with --game:")
+                for g in games:
+                    print(f"  --game {g.name!r}")
+            else:
+                print("No games detected. Select a library: rigdoctor games libraries --all")
+            return 1
+        pid = diagnostic.start(game=game, interval=args.interval)
+        time.sleep(1.0)
+        if pid and reccontrol.pid_alive(pid):
+            print(f"Diagnostic capture started for {game!r} (pid {pid}).")
+            print("  Play your game. When you're done (or after a crash + reboot):")
+            print("    rigdoctor diagnose finish")
+            return 0
+        print(f"Capture failed to start; see {config.SPAWN_LOG}")
+        return 1
+
+    if sub == "status":
+        status = diagnostic.active()
+        if not status:
+            print("No diagnostic capture is running.")
+            return 0
+        game = status.get("game") or "—"
+        print(f"Capturing for {game!r}: {status.get('samples', 0)} samples"
+              + (" · GPU-lost seen" if status.get("gpu_lost") else ""))
+        return 0
+
+    # finish
+    if not reccontrol.running_pid() and not config.DIAG_LOG.exists():
+        print("No diagnostic to analyze. Start one with: rigdoctor diagnose start --game <name>")
+        return 1
+    print("Stopping capture and analyzing…\n")
+    result = diagnostic.finish(last_n=args.last)
+    from .render import render_health, render_summary
+
+    if result.game:
+        print(f"Diagnostic — {result.game}\n")
+    print(render_summary(result.summary, log_path=config.DIAG_LOG))
+    print("\n" + render_health(result.findings, title="Findings"))
+    return 0
+
+
 def cmd_gameenv(args) -> int:
     from dataclasses import asdict
 
@@ -470,6 +542,7 @@ def build_parser() -> argparse.ArgumentParser:
     run_p = rec_sub.add_parser("run", help="run the capture loop in the foreground (systemd-friendly)")
     run_p.add_argument("-n", "--interval", type=float, default=None, help="sampling interval (s)")
     run_p.add_argument("-o", "--out", default=None, help="log file path")
+    run_p.add_argument("--game", default=None, help="tag the capture with a game name (M6/diagnose)")
     run_p.set_defaults(func=cmd_record_run)
 
     start_p = rec_sub.add_parser("start", help="start recording in the background")
@@ -519,6 +592,19 @@ def build_parser() -> argparse.ArgumentParser:
     env_p = sub.add_parser("gameenv", help="gaming environment checks (M6): flag stability/perf settings")
     env_p.add_argument("--json", action="store_true", help="output JSON instead of text")
     env_p.set_defaults(func=cmd_gameenv)
+
+    diag_p = sub.add_parser("diagnose", help="guided diagnostic: capture while gaming, then analyze")
+    diag_sub = diag_p.add_subparsers(dest="diagnose_cmd")
+    diag_start = diag_sub.add_parser("start", help="start a focused capture for a game")
+    diag_start.add_argument("--game", default=None, help="game name to focus on")
+    diag_start.add_argument("--appid", default=None, help="Steam appid to focus on (resolved to a name)")
+    diag_start.add_argument("-n", "--interval", type=float, default=None, help="sampling interval (s)")
+    diag_start.set_defaults(func=cmd_diagnose)
+    diag_sub.add_parser("status", help="show the in-progress diagnostic").set_defaults(func=cmd_diagnose)
+    diag_finish = diag_sub.add_parser("finish", help="stop the capture and analyze it")
+    diag_finish.add_argument("--last", type=int, default=10, help="recent samples to show")
+    diag_finish.set_defaults(func=cmd_diagnose)
+    diag_p.set_defaults(func=cmd_diagnose, diagnose_cmd=None, last=10)
     return p
 
 

src/rigdoctor/config.py

@@ -23,6 +23,9 @@ CONFIG_FILE = CONFIG_DIR / "config.toml"
 
 # Crash-capture logger (M3)
 LOG_FILE = LOG_DIR / "capture.jsonl"
+# Guided diagnostic (M6/D12): a focused capture writes here, separate from the always-on
+# crash log, so its report covers only that session's window.
+DIAG_LOG = LOG_DIR / "diagnostic.jsonl"
 STATUS_FILE = STATE_DIR / "recorder.json"
 PID_FILE = STATE_DIR / "recorder.pid"
 SPAWN_LOG = STATE_DIR / "recorder.out"

src/rigdoctor/core/catalog.py

@@ -45,4 +45,23 @@ COMPONENTS: tuple[Component, ...] = (
         "libsecret", "Encrypted token storage", "Updates",
         "Store the update token in the OS keyring, encrypted", ("libsecret-tools",), "secret-tool",
     ),
+    Component(
+        "gamemode", "Feral GameMode", "Gaming",
+        "Auto-applies performance tweaks (CPU governor, scheduling) while a game runs",
+        ("gamemode",), "gamemoderun",
+    ),
+    Component(
+        "mangohud", "MangoHud", "Gaming",
+        "In-game overlay for FPS, frame times, and temperatures", ("mangohud",), "mangohud",
+    ),
+    Component(
+        "cpupower", "cpupower", "Gaming",
+        "Read/set the CPU frequency governor (e.g. performance for gaming)",
+        ("linux-tools-common", "linux-tools-generic"), "cpupower",
+    ),
 )
+
+
+def by_id(component_id: str) -> Component | None:
+    """Look up a catalog component by its id (None if unknown)."""
+    return next((c for c in COMPONENTS if c.id == component_id), None)

src/rigdoctor/core/diagnostic.py

@@ -0,0 +1,84 @@
+"""Guided diagnostic session (SPEC §4 / ARCHITECTURE §7.1): orchestrate M3 + M4.
+
+The seed use case, one flow: **pick a game** → **focused crash-capture** scoped to that
+session (M3, tagged with the game) → on **finish**, **scan & analyze** (M4 health report)
+over the captured window + system logs → return a prioritized result. This is not a new
+module — it's a single shared callable so the CLI, GUI, and tray run the identical flow.
+
+The capture is **manually bracketed** (start/finish) for now; auto start/stop on game launch
+(the D12 wrapper/watcher) plugs in here later without changing the result shape.
+"""
+
+from __future__ import annotations
+
+import time
+from dataclasses import dataclass
+
+from .. import config
+from . import reccontrol
+from .crashlog import Summary, summarize
+from .health import Finding
+
+
+@dataclass
+class DiagnosticResult:
+    game: str | None
+    summary: Summary           # capture window: peak temps/power, events, last samples (M3)
+    findings: list[Finding]    # health findings: Xid/SMART/driver/etc. (M4)
+
+
+def _clear_diag_log() -> None:
+    """Each diagnostic is a fresh focused capture — drop any previous session + segments."""
+    base = config.DIAG_LOG
+    for p in [base, *base.parent.glob(base.name + ".*")]:
+        try:
+            p.unlink()
+        except OSError:
+            pass
+
+
+def start(game: str | None = None, interval: float | None = None) -> int | None:
+    """Begin a focused capture, tagged with the game, into the dedicated diagnostic log.
+    Returns the pid, or None if a capture is already running."""
+    if reccontrol.running_pid():
+        return None
+    _clear_diag_log()
+    return reccontrol.start_background(interval=interval, out=str(config.DIAG_LOG), game=game)
+
+
+def is_running() -> bool:
+    return reccontrol.running_pid() is not None
+
+
+def active() -> dict | None:
+    """Status of the in-progress session (running flag, game, samples), or None if idle."""
+    if not is_running():
+        return None
+    return reccontrol.read_status()
+
+
+def _await_stopped(timeout: float = 6.0) -> None:
+    deadline = time.monotonic() + timeout
+    while reccontrol.running_pid() and time.monotonic() < deadline:
+        time.sleep(0.1)
+
+
+def _game_from_summary(summary: Summary) -> str | None:
+    """Recover the focused game from the log's 'game' event (survives a crash + reboot)."""
+    for _ts, kind, detail in reversed(summary.events):
+        if kind == "game" and detail:
+            return detail
+    return None
+
+
+def finish(last_n: int = 10, log_path=None) -> DiagnosticResult:
+    """Stop the capture (if running), summarize the window, and run the health report."""
+    from .health import run_health_checks
+
+    reccontrol.stop_background()
+    _await_stopped()
+    path = log_path or config.DIAG_LOG
+    summary = summarize(path, last_n=last_n)
+    game = _game_from_summary(summary) or (reccontrol.read_status() or {}).get("game")
+    findings = run_health_checks()
+    return DiagnosticResult(game=game, summary=summary, findings=findings)

src/rigdoctor/core/fixes.py

@@ -0,0 +1,177 @@
+"""Apply runtime-reversible system tunables (M6) — a limited, consent-gated exception to
+the read-only stance (D9, amended by D22).
+
+Only safe settings that take effect immediately, need no reboot, and revert on reboot are
+applyable here: CPU governor, NVIDIA persistence mode, PCIe ASPM policy, vm.swappiness, and
+Transparent HugePages. Each is set by a single privileged command (one pkexec prompt). The
+chosen value is validated against the live options before building the command, and writes go
+to sysfs / procfs (or `nvidia-smi`) — never the GRUB cmdline or a persistent config file.
+Riskier fixes (GRUB-based PCIe ASPM-off, CPU mitigations) stay suggestion-only.
+"""
+
+from __future__ import annotations
+
+import os
+import shlex
+import shutil
+import subprocess
+from collections.abc import Callable
+from dataclasses import dataclass
+from pathlib import Path
+
+
+@dataclass
+class Tunable:
+    id: str
+    label: str            # e.g. "CPU governor"
+    options: list[str]    # selectable values (live, from the system)
+    current: str | None   # the value in effect now (preselect this in the dropdown)
+    note: str = ""        # caveat shown by the control, e.g. "resets on reboot"
+
+
+def _read(path: str) -> str | None:
+    try:
+        return Path(path).read_text()
+    except OSError:
+        return None
+
+
+def _bracketed(text: str) -> tuple[list[str], str | None]:
+    """Parse a sysfs 'a [b] c' enum into (options, active)."""
+    options = [tok.strip("[]") for tok in text.split()]
+    active = next((tok.strip("[]") for tok in text.split() if tok.startswith("[")), None)
+    return options, active
+
+
+# --- individual tunables: a state reader + a command builder per id -------------------
+
+_GOV = "/sys/devices/system/cpu"
+
+
+def _cpu_governor() -> Tunable | None:
+    cur = _read(f"{_GOV}/cpu0/cpufreq/scaling_governor")
+    if cur is None:
+        return None
+    avail = _read(f"{_GOV}/cpu0/cpufreq/scaling_available_governors")
+    options = avail.split() if avail and avail.strip() else ["performance", "powersave", "schedutil"]
+    return Tunable("cpu_governor", "CPU governor", options, cur.strip(), "applies now; resets on reboot")
+
+
+def _cpu_governor_cmd(value: str) -> list[str]:
+    return ["/bin/sh", "-c",
+            f'for f in {_GOV}/cpu*/cpufreq/scaling_governor; do echo {shlex.quote(value)} > "$f"; done']
+
+
+def _nvidia_persistence() -> Tunable | None:
+    if shutil.which("nvidia-smi") is None:
+        return None
+    try:
+        proc = subprocess.run(
+            ["nvidia-smi", "--query-gpu=persistence_mode", "--format=csv,noheader"],
+            capture_output=True, text=True, timeout=10,
+        )
+    except (subprocess.SubprocessError, OSError):
+        return None
+    state = proc.stdout.strip().splitlines()[0].strip().lower() if proc.stdout.strip() else ""
+    current = "Enabled" if state.startswith("enabled") else ("Disabled" if state.startswith("disabled") else None)
+    return Tunable("nvidia_persistence", "NVIDIA persistence mode", ["Enabled", "Disabled"], current,
+                   "resets on reboot (enable nvidia-persistenced to persist)")
+
+
+def _nvidia_persistence_cmd(value: str) -> list[str]:
+    return ["nvidia-smi", "-pm", "1" if value == "Enabled" else "0"]
+
+
+def _pcie_aspm() -> Tunable | None:
+    text = _read("/sys/module/pcie_aspm/parameters/policy")
+    if not text:
+        return None
+    options, active = _bracketed(text)
+    return Tunable("pcie_aspm", "PCIe ASPM policy", options, active, "applies now; resets on reboot")
+
+
+def _pcie_aspm_cmd(value: str) -> list[str]:
+    return ["/bin/sh", "-c", f'echo {shlex.quote(value)} > /sys/module/pcie_aspm/parameters/policy']
+
+
+def _swappiness() -> Tunable | None:
+    text = _read("/proc/sys/vm/swappiness")
+    if text is None or not text.strip().isdigit():
+        return None
+    cur = text.strip()
+    options = ["0", "10", "30", "60", "100"]
+    if cur not in options:
+        options = sorted(set(options) | {cur}, key=int)
+    return Tunable("swappiness", "vm.swappiness", options, cur, "applies now; resets on reboot")
+
+
+def _swappiness_cmd(value: str) -> list[str]:
+    return ["/bin/sh", "-c", f'echo {shlex.quote(value)} > /proc/sys/vm/swappiness']
+
+
+def _thp() -> Tunable | None:
+    text = _read("/sys/kernel/mm/transparent_hugepage/enabled")
+    if not text:
+        return None
+    options, active = _bracketed(text)
+    return Tunable("thp", "Transparent HugePages", options, active, "applies now; resets on reboot")
+
+
+def _thp_cmd(value: str) -> list[str]:
+    return ["/bin/sh", "-c", f'echo {shlex.quote(value)} > /sys/kernel/mm/transparent_hugepage/enabled']
+
+
+_TUNABLES: dict[str, tuple[Callable[[], Tunable | None], Callable[[str], list[str]]]] = {
+    "cpu_governor": (_cpu_governor, _cpu_governor_cmd),
+    "nvidia_persistence": (_nvidia_persistence, _nvidia_persistence_cmd),
+    "pcie_aspm": (_pcie_aspm, _pcie_aspm_cmd),
+    "swappiness": (_swappiness, _swappiness_cmd),
+    "thp": (_thp, _thp_cmd),
+}
+
+
+# --- public API -----------------------------------------------------------------------
+
+def get_tunable(fix_id: str) -> Tunable | None:
+    """Live state (options + current value) for a fix id, or None if not applicable here."""
+    fns = _TUNABLES.get(fix_id)
+    return fns[0]() if fns else None
+
+
+def apply_command(fix_id: str, value: str) -> list[str] | None:
+    """The privileged command to set fix_id=value, or None if unknown/invalid.
+
+    The value is validated against the *live* options, so only a real, currently-available
+    setting can ever be turned into a command.
+    """
+    fns = _TUNABLES.get(fix_id)
+    if not fns:
+        return None
+    state = fns[0]()
+    if state is None or value not in state.options:
+        return None
+    return fns[1](value)
+
+
+def _elevate(cmd: list[str]) -> list[str]:
+    prog = shutil.which(cmd[0]) or cmd[0]  # pkexec needs an absolute program path
+    cmd = [prog, *cmd[1:]]
+    if os.geteuid() == 0:
+        return cmd
+    if shutil.which("pkexec"):
+        return ["pkexec", *cmd]
+    if shutil.which("sudo"):
+        return ["sudo", *cmd]
+    return cmd  # no escalation available — will likely fail, surfaced to the caller
+
+
+def apply(fix_id: str, value: str) -> tuple[int, str]:
+    """Apply fix_id=value via a single elevated command. Returns (exit_code, output)."""
+    cmd = apply_command(fix_id, value)
+    if cmd is None:
+        return (1, f"Unknown or unavailable setting: {fix_id}={value}")
+    try:
+        proc = subprocess.run(_elevate(cmd), capture_output=True, text=True, timeout=120)
+        return (proc.returncode, proc.stdout + proc.stderr)
+    except (subprocess.SubprocessError, OSError) as exc:
+        return (1, str(exc))

src/rigdoctor/core/gameenv.py

@@ -49,15 +49,18 @@ def evaluate_aspm(policy_text: str | None) -> Finding | None:
             WARNING, "PCIe", f"PCIe ASPM is in power-saving mode ({active})",
             "Aggressive PCIe Active-State Power Management can cause the GPU to drop off the "
             "bus under load (Xid 79) or stutter — the seed-case failure mode.",
-            "Disable ASPM via the kernel cmdline: add `pcie_aspm=off` (and optionally "
+            "Set the policy to performance below (live), or for a permanent change add "
-            "`pcie_aspm.policy=performance`) in GRUB, then `sudo update-grub` and reboot.",
+            "`pcie_aspm=off` in GRUB, then `sudo update-grub` and reboot.",
+            fix="pcie_aspm",
         )
     if active == "performance":
-        return Finding(OK, "PCIe", "PCIe ASPM set to performance", "ASPM power-saving is disabled.")
+        return Finding(OK, "PCIe", "PCIe ASPM set to performance", "ASPM power-saving is disabled.",
+                       fix="pcie_aspm")
     return Finding(
         INFO, "PCIe", f"PCIe ASPM policy: {active}",
         "ASPM is left to the kernel/BIOS default.",
-        "If you see GPU bus-drop events (Xid 79), try `pcie_aspm=off` on the kernel cmdline.",
+        "If you see GPU bus-drop events (Xid 79), set the policy to performance below.",
+        fix="pcie_aspm",
     )
 
 
@@ -84,11 +87,13 @@ def check_gpu_persistence() -> list[Finding]:
             INFO, "GPU", "NVIDIA persistence mode is off",
             "The driver unloads when no client is attached, adding latency on first GPU "
             "access and churning state between game launches.",
-            "Enable it: `sudo nvidia-smi -pm 1` (per-boot), or enable the "
+            "Enable it below (per-boot), or enable the `nvidia-persistenced` service to "
-            "`nvidia-persistenced` service to make it permanent.",
+            "make it permanent.",
+            fix="nvidia_persistence",
         )]
     if state.lower().startswith("enabled"):
-        return [Finding(OK, "GPU", "NVIDIA persistence mode on", "The driver stays resident.")]
+        return [Finding(OK, "GPU", "NVIDIA persistence mode on", "The driver stays resident.",
+                        fix="nvidia_persistence")]
     return []
 
 
@@ -99,18 +104,20 @@ def evaluate_governor(governors: set[str]) -> Finding | None:
         return None
     shown = ", ".join(sorted(governors))
     if governors == {"performance"}:
-        return Finding(OK, "CPU", "CPU governor: performance", "CPUs run at full clocks under load.")
+        return Finding(OK, "CPU", "CPU governor: performance", "CPUs run at full clocks under load.",
+                       fix="cpu_governor")
     if "powersave" in governors:
         return Finding(
             WARNING, "CPU", f"CPU governor set to power-saving ({shown})",
             "A powersave governor caps CPU frequency and can bottleneck frame times.",
-            "Set performance: `sudo cpupower frequency-set -g performance` "
+            "Set it to performance below (or install GameMode to switch it per-game).",
-            "(install `linux-tools-common`/`cpupower`), or install GameMode to switch it per-game.",
+            fix="cpu_governor",
         )
     return Finding(
         INFO, "CPU", f"CPU governor: {shown}",
         "A dynamic governor scales with load; usually fine.",
-        "For the most consistent frame pacing, `performance` (or GameMode) avoids ramp-up lag.",
+        "For the most consistent frame pacing, set performance below (or use GameMode).",
+        fix="cpu_governor",
     )
 
 
@@ -137,6 +144,7 @@ def check_gamemode() -> list[Finding]:
         "GameMode auto-applies performance tweaks (governor, scheduling) for the duration of a game.",
         "Install it: `sudo apt install gamemode`, then launch games with `gamemoderun %command%` "
         "(or use a global Steam launch option).",
+        action="gamemode",
     )]
 
 
@@ -147,6 +155,7 @@ def check_mangohud() -> list[Finding]:
         INFO, "Tools", "MangoHud not installed",
         "MangoHud overlays live FPS, frame times, and temps in-game — handy for spotting stutter.",
         "Install it: `sudo apt install mangohud`, then launch with `mangohud %command%`.",
+        action="mangohud",
     )]
 
 
@@ -158,9 +167,11 @@ def evaluate_swappiness(value: int) -> Finding:
             INFO, "Memory", f"vm.swappiness is high ({value})",
             "A high swappiness lets the kernel swap out memory eagerly, which can cause "
             "hitching during gaming on systems with ample RAM.",
-            "Lower it: `sudo sysctl vm.swappiness=10` (persist in /etc/sysctl.d/99-rigdoctor.conf).",
+            "Lower it below (e.g. 10); applies immediately.",
+            fix="swappiness",
         )
-    return Finding(OK, "Memory", f"vm.swappiness is {value}", "Swapping is conservative.")
+    return Finding(OK, "Memory", f"vm.swappiness is {value}", "Swapping is conservative.",
+                   fix="swappiness")
 
 
 def check_swappiness() -> list[Finding]:
@@ -204,7 +215,8 @@ def check_thp() -> list[Finding]:
         return [Finding(
             INFO, "Memory", "Transparent HugePages disabled (never)",
             "Some workloads benefit from THP; 'madvise' lets apps opt in without the downsides of 'always'.",
-            "Optional: `echo madvise | sudo tee /sys/kernel/mm/transparent_hugepage/enabled`.",
+            "Optional: set 'madvise' below; applies immediately.",
+            fix="thp",
         )]
     return []
 

src/rigdoctor/core/health.py

@@ -27,6 +27,8 @@ class Finding:
     title: str
     detail: str = ""
     suggestion: str = ""
+    action: str = ""  # optional: id of an installable catalog component (for an Install button)
+    fix: str = ""     # optional: id of an applyable runtime tunable (for an Apply dropdown, M6)
 
 
 # --- NVIDIA Xid knowledge (the seed crash is Xid 79) --------------------------

src/rigdoctor/core/reccontrol.py

@@ -38,7 +38,9 @@ def read_status() -> dict | None:
         return None
 
 
-def start_background(interval: float | None = None, out: str | None = None) -> int | None:
+def start_background(
+    interval: float | None = None, out: str | None = None, game: str | None = None
+) -> int | None:
     """Spawn a detached `record run`. Returns the child pid, or None if already running."""
     if running_pid():
         return None
@@ -48,6 +50,8 @@ def start_background(interval: float | None = None, out: str | None = None) -> i
         cmd += ["--interval", str(interval)]
     if out:
         cmd += ["--out", out]
+    if game:
+        cmd += ["--game", game]
     out_fh = open(config.SPAWN_LOG, "a")
     proc = subprocess.Popen(
         cmd,

src/rigdoctor/core/recorder.py

@@ -27,12 +27,14 @@ class Recorder:
         backups: int = 10,
         status_path=None,
         sampler: Sampler | None = None,
+        game: str | None = None,
     ) -> None:
         self.interval = interval
         self.sampler = sampler or Sampler(available_sources())
         self.writer = CrashLogWriter(log_path, max_bytes, backups)
         self.log_path = Path(log_path)
         self.status_path = Path(status_path) if status_path else None
+        self.game = game or None
         self.samples = 0
         self._stop = threading.Event()
         self._gpu_lost = False
@@ -43,6 +45,8 @@ class Recorder:
 
     def run(self) -> None:
         self.writer.write_event("session-start", f"interval={self.interval:g}s")
+        if self.game:
+            self.writer.write_event("game", self.game)  # tag the focused-diagnostic target
         self._write_status(running=True)
         try:
             while not self._stop.is_set():
@@ -81,6 +85,7 @@ class Recorder:
             "samples": self.samples,
             "updated": time.time(),
             "gpu_lost": self._gpu_lost,
+            "game": self.game,
         }
         if sample is not None:
             data["latest"] = headline(sample)

src/rigdoctor/core/steam.py

@@ -15,6 +15,8 @@ from __future__ import annotations
 
 import json
 import os
+import shutil
+import subprocess
 import time
 from dataclasses import asdict, dataclass
 from pathlib import Path
@@ -351,6 +353,24 @@ def acknowledge_new() -> None:
 
 # --- formatting -----------------------------------------------------------------------
 
+def launch_game(appid: str) -> bool:
+    """Best-effort: ask Steam to launch a game by appid (steam:// URL). Non-blocking."""
+    if not appid:
+        return False
+    url = f"steam://rungameid/{appid}"
+    for cmd in (["steam", url], ["xdg-open", url]):
+        if shutil.which(cmd[0]):
+            try:
+                subprocess.Popen(
+                    cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,
+                    stdin=subprocess.DEVNULL, start_new_session=True,
+                )
+                return True
+            except (OSError, subprocess.SubprocessError):
+                continue
+    return False
+
+
 def human_size(num_bytes: int) -> str:
     if num_bytes <= 0:
         return "—"

src/rigdoctor/gui/diagnostic_dialog.py

@@ -0,0 +1,81 @@
+"""Results view for a guided diagnostic session (M6/D12): capture summary + findings."""
+
+from __future__ import annotations
+
+from PySide6.QtCore import Qt
+from PySide6.QtGui import QFont
+from PySide6.QtWidgets import (
+    QDialog,
+    QFrame,
+    QHBoxLayout,
+    QLabel,
+    QPushButton,
+    QScrollArea,
+    QVBoxLayout,
+    QWidget,
+)
+
+from ..render import render_summary
+from .widgets import finding_card
+
+
+class DiagnosticDialog(QDialog):
+    def __init__(self, result, parent=None) -> None:
+        super().__init__(parent)
+        self.setWindowTitle(f"Diagnostic — {result.game}" if result.game else "Diagnostic")
+        self.resize(660, 680)
+
+        root = QVBoxLayout(self)
+        root.setContentsMargins(20, 18, 20, 16)
+        root.setSpacing(14)
+
+        title = QLabel(f"Diagnostic — {result.game}" if result.game else "Diagnostic")
+        title.setObjectName("PageTitle")
+        root.addWidget(title)
+
+        scroll = QScrollArea()
+        scroll.setWidgetResizable(True)
+        scroll.setFrameShape(QFrame.Shape.NoFrame)
+        scroll.setStyleSheet("background: transparent;")
+        body = QWidget()
+        col = QVBoxLayout(body)
+        col.setContentsMargins(0, 0, 0, 0)
+        col.setSpacing(10)
+        col.setAlignment(Qt.AlignmentFlag.AlignTop)
+
+        # Capture window summary (peaks / events / last samples) — monospace for the columns.
+        cap_head = QLabel("Capture")
+        cap_head.setStyleSheet("font-weight: 700; background: transparent;")
+        col.addWidget(cap_head)
+        summary = QLabel(render_summary(result.summary))
+        summary.setObjectName("Report")
+        summary.setFont(QFont("monospace"))
+        summary.setTextInteractionFlags(Qt.TextInteractionFlag.TextSelectableByMouse)
+        summary.setWordWrap(False)
+        summary.setStyleSheet(
+            "background: #0d0f13; color: #cfd3da; border: 1px solid #2a2f39; "
+            "border-radius: 8px; padding: 10px;"
+        )
+        col.addWidget(summary)
+
+        find_head = QLabel(f"Findings ({len(result.findings)})")
+        find_head.setStyleSheet("font-weight: 700; background: transparent;")
+        col.addWidget(find_head)
+        if result.findings:
+            for finding in result.findings:
+                col.addWidget(finding_card(finding))
+        else:
+            none = QLabel("No findings.")
+            none.setObjectName("Muted")
+            col.addWidget(none)
+
+        scroll.setWidget(body)
+        root.addWidget(scroll, 1)
+
+        buttons = QHBoxLayout()
+        buttons.addStretch(1)
+        close = QPushButton("Close")
+        close.setObjectName("PrimaryButton")
+        close.clicked.connect(self.accept)
+        buttons.addWidget(close)
+        root.addLayout(buttons)

src/rigdoctor/gui/environment_page.py

@@ -19,13 +19,27 @@ from PySide6.QtWidgets import (
 from .widgets import finding_card
 
 
+def _fail_reason(out: str) -> str:
+    """Turn the failed command's output into a short, human reason."""
+    low = (out or "").lower()
+    if "not authorized" in low or "dismissed" in low or "authentication" in low:
+        return "cancelled at the password prompt"
+    if "operation not permitted" in low or "invalid argument" in low or "permission denied" in low:
+        return "the system rejected the change (it may be locked by BIOS/kernel)"
+    last = next((ln.strip() for ln in reversed((out or "").splitlines()) if ln.strip()), "")
+    return (last[:80] or "no privileges, or cancelled")
+
+
 class EnvironmentPage(QWidget):
-    _result = Signal(object)  # list[Finding]
+    _result = Signal(object)       # list[Finding]
+    _action_done = Signal(object)  # (label, rc, output) — install or apply finished
 
     def __init__(self) -> None:
         super().__init__()
         self.setObjectName("Page")
         self._result.connect(self._render_findings)
+        self._action_done.connect(self._on_action_done)
+        self._busy = False
 
         root = QVBoxLayout(self)
         root.setContentsMargins(20, 18, 20, 18)
@@ -100,5 +114,43 @@ class EnvironmentPage(QWidget):
             f"{time.strftime('%H:%M:%S')}"
         )
         for finding in findings:
-            self._list.addWidget(finding_card(finding))
+            self._list.addWidget(finding_card(finding, on_install=self._install, on_apply=self._apply))
         self._list.addStretch(1)
+
+    def _install(self, component) -> None:
+        if self._busy:
+            return
+        self._busy = True
+        self._run_btn.setEnabled(False)
+        self._status.setText(f"Installing {component.name}… (may prompt for your password)")
+        threading.Thread(target=self._work_install, args=(component,), daemon=True).start()
+
+    def _work_install(self, component) -> None:
+        from ..core import installer
+
+        rc, out = installer.install_packages(list(component.apt))
+        self._action_done.emit((component.name, rc, out))
+
+    def _apply(self, fix_id: str, value: str) -> None:
+        if self._busy:
+            return
+        self._busy = True
+        self._run_btn.setEnabled(False)
+        self._status.setText(f"Applying {value}… (may prompt for your password)")
+        threading.Thread(target=self._work_apply, args=(fix_id, value), daemon=True).start()
+
+    def _work_apply(self, fix_id: str, value: str) -> None:
+        from ..core import fixes
+
+        rc, out = fixes.apply(fix_id, value)
+        self._action_done.emit((value, rc, out))
+
+    def _on_action_done(self, result) -> None:
+        label, rc, out = result
+        self._busy = False
+        if rc == 0:
+            self._status.setText(f"{label} applied — re-checking…")
+            self._run()  # re-run so the finding reflects the new state
+        else:
+            self._run_btn.setEnabled(True)
+            self._status.setText(f"'{label}' failed — {_fail_reason(out)}")

src/rigdoctor/gui/games_page.py

@@ -17,6 +17,7 @@ from PySide6.QtWidgets import (
     QFrame,
     QHBoxLayout,
     QLabel,
+    QMessageBox,
     QPushButton,
     QScrollArea,
     QVBoxLayout,
@@ -24,10 +25,11 @@ from PySide6.QtWidgets import (
 )
 
 from ..config import load_config, update_config
+from .diagnostic_dialog import DiagnosticDialog
 from .theme import ACCENT, GOOD, MUTED
 
 
-def _game_row(name: str, sublabel: str, size: str, is_new: bool) -> QFrame:
+def _game_row(name: str, sublabel: str, size: str, is_new: bool, appid: str = "", on_diagnose=None) -> QFrame:
     card = QFrame()
     card.setObjectName("Card")
     h = QHBoxLayout(card)
@@ -59,6 +61,13 @@ def _game_row(name: str, sublabel: str, size: str, is_new: bool) -> QFrame:
     size_label.setMinimumWidth(80)
     size_label.setAlignment(Qt.AlignmentFlag.AlignRight | Qt.AlignmentFlag.AlignVCenter)
     h.addWidget(size_label, 0)
+
+    if on_diagnose is not None:
+        diag_btn = QPushButton("Run Diagnostic")
+        diag_btn.setObjectName("ActionButton")
+        diag_btn.setCursor(Qt.CursorShape.PointingHandCursor)
+        diag_btn.clicked.connect(lambda: on_diagnose(name, appid))
+        h.addWidget(diag_btn, 0)
     return card
 
 
@@ -66,14 +75,17 @@ class GamesPage(QWidget):
     _libraries_ready = Signal(object)  # list[dict(path, label, count, selected)]
     _scanned = Signal(object)          # steam.ScanResult
     new_count_changed = Signal(int)    # newly-installed game count (for the nav badge)
+    _diag_done = Signal(object)        # DiagnosticResult — focused capture analyzed
 
     def __init__(self) -> None:
         super().__init__()
         self.setObjectName("Page")
         self._libraries_ready.connect(self._render_libraries)
         self._scanned.connect(self._render_games)
+        self._diag_done.connect(self._on_diag_done)
         self._busy = False
         self._new_appids: set[str] = set()
+        self._diag_game: str | None = None
 
         root = QVBoxLayout(self)
         root.setContentsMargins(20, 18, 20, 18)
@@ -93,6 +105,31 @@ class GamesPage(QWidget):
         header.addWidget(self._rescan_btn)
         root.addLayout(header)
 
+        # In-progress diagnostic banner (hidden until a focused capture is running).
+        self._banner = QFrame()
+        self._banner.setObjectName("Card")
+        self._banner.setStyleSheet(f"#Card {{ border: 1px solid {ACCENT}; }}")
+        banner_h = QHBoxLayout(self._banner)
+        banner_h.setContentsMargins(16, 10, 16, 10)
+        banner_h.setSpacing(10)
+        self._banner_label = QLabel("")
+        self._banner_label.setWordWrap(True)
+        self._banner_label.setStyleSheet(f"color: {ACCENT}; font-weight: 700; background: transparent;")
+        banner_h.addWidget(self._banner_label, 1)
+        self._finish_btn = QPushButton("Finish && analyze")  # && → literal & (not a mnemonic)
+        self._finish_btn.setObjectName("ActionButton")
+        self._finish_btn.clicked.connect(self._finish_diagnostic)
+        banner_h.addWidget(self._finish_btn)
+        self._discard_btn = QPushButton("Discard")
+        self._discard_btn.clicked.connect(self._discard_diagnostic)
+        banner_h.addWidget(self._discard_btn)
+        self._banner.hide()
+        root.addWidget(self._banner)
+
+        self._diag_timer = QTimer(self)
+        self._diag_timer.setInterval(1000)
+        self._diag_timer.timeout.connect(self._poll_diag)
+
         # Libraries (opt-in checkboxes)
         lib_card = QFrame()
         lib_card.setObjectName("Card")
@@ -233,9 +270,107 @@ class GamesPage(QWidget):
                 os.path.basename(g.library.rstrip("/")) or g.library,
                 steam.human_size(g.size_bytes),
                 g.appid in new_appids,
+                appid=g.appid,
+                on_diagnose=self._start_diagnostic,
             ))
         self._list.addStretch(1)
 
+    # --- guided diagnostic (M6/D12) ---------------------------------------------------
+
+    def _start_diagnostic(self, name: str, appid: str = "") -> None:
+        from ..core import diagnostic, steam
+
+        if diagnostic.is_running():
+            QMessageBox.information(
+                self, "RigDoctor",
+                "A capture is already running — finish or discard it first.")
+            return
+
+        # Tell the user what the flow actually is, and offer to launch the game for them.
+        box = QMessageBox(self)
+        box.setIcon(QMessageBox.Icon.Information)
+        box.setWindowTitle(f"Run Diagnostic — {name}")
+        box.setText(f"Record a focused diagnostic while you play {name}?")
+        box.setInformativeText(
+            "RigDoctor will capture sensors in the background. Then:\n\n"
+            "1.  Play the game and try to reproduce the freeze / black screen / crash.\n"
+            "2.  When you're done — or after a hard freeze and reboot — come back here and "
+            "click “Finish & analyze”.\n\n"
+            "Your readings are saved continuously, so even a hard lock won't lose them."
+        )
+        launch_btn = box.addButton("Launch game && start", QMessageBox.ButtonRole.AcceptRole)
+        start_btn = box.addButton("Start without launching", QMessageBox.ButtonRole.ActionRole)
+        box.addButton("Cancel", QMessageBox.ButtonRole.RejectRole)
+        if not appid:
+            launch_btn.setEnabled(False)  # no appid → can't ask Steam to launch it
+        box.exec()
+        clicked = box.clickedButton()
+        if clicked not in (launch_btn, start_btn):
+            return
+
+        if diagnostic.start(game=name) is None:
+            QMessageBox.warning(self, "RigDoctor", "Couldn't start the capture.")
+            return
+        launched = steam.launch_game(appid) if clicked is launch_btn else False
+        self._diag_game = name
+        self._finish_btn.setEnabled(True)
+        self._discard_btn.setEnabled(True)
+        self._banner.show()
+        self._diag_timer.start()
+        self._poll_diag()
+        if clicked is launch_btn and not launched:
+            QMessageBox.information(
+                self, "RigDoctor",
+                "Recording started, but couldn't launch the game automatically — "
+                "launch it yourself, then click “Finish & analyze” when you're done.")
+
+    def _poll_diag(self) -> None:
+        from ..core import diagnostic
+
+        status = diagnostic.active()
+        if not status:
+            self._diag_timer.stop()  # recorder exited on its own
+            return
+        samples = status.get("samples", 0)
+        lost = "  ·  ⚠ GPU-lost detected" if status.get("gpu_lost") else ""
+        game = status.get("game") or self._diag_game or "your game"
+        self._banner_label.setText(
+            f"● Recording {game} — play it and reproduce the problem, then click "
+            f"“Finish & analyze”.   ({samples} samples{lost})"
+        )
+
+    def _finish_diagnostic(self) -> None:
+        self._diag_timer.stop()
+        self._finish_btn.setEnabled(False)
+        self._discard_btn.setEnabled(False)
+        self._banner_label.setText("Analyzing… (running the health report)")
+        threading.Thread(target=self._work_finish, daemon=True).start()
+
+    def _work_finish(self) -> None:
+        from ..core import diagnostic
+
+        try:
+            result = diagnostic.finish()
+        except Exception:
+            result = None
+        self._diag_done.emit(result)
+
+    def _on_diag_done(self, result) -> None:
+        self._banner.hide()
+        self._finish_btn.setEnabled(True)
+        self._discard_btn.setEnabled(True)
+        if result is None:
+            QMessageBox.warning(self, "RigDoctor", "The diagnostic couldn't be analyzed.")
+            return
+        DiagnosticDialog(result, self).exec()
+
+    def _discard_diagnostic(self) -> None:
+        from ..core import reccontrol
+
+        self._diag_timer.stop()
+        reccontrol.stop_background()
+        self._banner.hide()
+
     # --- nav badge integration --------------------------------------------------------
 
     def showEvent(self, event) -> None:  # noqa: N802 (Qt override)
@@ -247,3 +382,13 @@ class GamesPage(QWidget):
 
             threading.Thread(target=steam.acknowledge_new, daemon=True).start()
             self.new_count_changed.emit(0)
+
+        # Reflect a capture that's still running (e.g. started earlier, navigated back).
+        from ..core import diagnostic
+
+        if diagnostic.is_running():
+            status = diagnostic.active() or {}
+            self._diag_game = status.get("game") or self._diag_game
+            self._banner.show()
+            if not self._diag_timer.isActive():
+                self._diag_timer.start()

src/rigdoctor/gui/theme.py

@@ -104,6 +104,15 @@ QPushButton#PrimaryButton {{ background: {ACCENT}; color: #06222e; border: none;
 QPushButton#PrimaryButton:hover {{ background: #5cc8fb; }}
 QPushButton#PrimaryButton:disabled {{ background: #27424f; color: #5f7c8a; }}
 
+/* Inline per-finding action buttons (Install / Apply). Outlined: bright accent text on the
+   dark card so it stays readable regardless of fill painting; fills accent on hover. */
+QPushButton#ActionButton {{
+    background: transparent; color: {ACCENT}; border: 1px solid {ACCENT};
+    border-radius: 8px; padding: 6px 16px; font-weight: 700; min-height: 18px;
+}}
+QPushButton#ActionButton:hover {{ background: {ACCENT}; color: #06222e; }}
+QPushButton#ActionButton:disabled {{ color: {MUTED}; border-color: {CARD_BORDER}; }}
+
 QDoubleSpinBox, QSpinBox {{
     background: #262b34; color: {TEXT}; border: 1px solid {CARD_BORDER};
     border-radius: 6px; padding: 4px 6px;
@@ -150,4 +159,13 @@ QLineEdit:focus, QPlainTextEdit:focus, QAbstractSpinBox:focus, QComboBox:focus {
     border: 1px solid {ACCENT};
 }}
 QLineEdit:disabled, QPlainTextEdit:disabled, QAbstractSpinBox:disabled {{ color: {MUTED}; }}
+
+/* The combo-box drop-down list is a separate popup view — unstyled it renders
+   light-on-light (same Fusion trap as the closed control above). */
+QComboBox QAbstractItemView {{
+    background: {CARD}; color: {TEXT};
+    border: 1px solid {CARD_BORDER}; outline: 0;
+    selection-background-color: {ACCENT}; selection-color: #06222e;
+}}
+QComboBox QAbstractItemView::item {{ padding: 5px 8px; min-height: 22px; }}
 """

src/rigdoctor/gui/widgets.py

@@ -5,6 +5,7 @@ from __future__ import annotations
 from PySide6.QtCore import QRectF, Qt
 from PySide6.QtGui import QColor, QFont, QPainter, QPen
 from PySide6.QtWidgets import (
+    QComboBox,
     QFrame,
     QHBoxLayout,
     QLabel,
@@ -26,8 +27,17 @@ _SEV = {
 }
 
 
-def finding_card(finding) -> QFrame:
+def finding_card(finding, on_install=None, on_apply=None) -> QFrame:
-    """A card for one M4/M6 Finding (severity-colored title, detail, suggested fix)."""
+    """A card for one M4/M6 Finding (severity-colored title, detail, suggested fix).
+
+    If the finding names an installable catalog component (``finding.action``) and an
+    ``on_install(component)`` callback is given, an "Install" button is shown — so a
+    "tool not installed" finding becomes one click instead of a copy-pasted apt command.
+
+    If the finding names a runtime tunable (``finding.fix``) and an ``on_apply(fix_id,
+    value)`` callback is given, a dropdown of the live options + an Apply button is shown
+    (M6 live fixes — D22).
+    """
     label, color = _SEV.get(finding.severity, ("?", MUTED))
     card = QFrame()
     card.setObjectName("Card")
@@ -50,9 +60,65 @@ def finding_card(finding) -> QFrame:
         suggestion.setStyleSheet(f"color: {ACCENT}; background: transparent;")
         suggestion.setWordWrap(True)
         v.addWidget(suggestion)
+
+    component = _installable_component(finding) if on_install else None
+    if component is not None:
+        row = QHBoxLayout()
+        row.addStretch(1)
+        btn = QPushButton(f"Install {component.name}")
+        btn.setObjectName("ActionButton")
+        btn.setCursor(Qt.CursorShape.PointingHandCursor)
+        btn.clicked.connect(lambda: on_install(component))
+        row.addWidget(btn)
+        v.addLayout(row)
+
+    tunable = _tunable(finding) if on_apply else None
+    if tunable is not None and tunable.options:
+        row = QHBoxLayout()
+        name = QLabel(f"{tunable.label}:")
+        name.setObjectName("Muted")
+        combo = QComboBox()
+        combo.addItems(tunable.options)
+        if tunable.current in tunable.options:
+            combo.setCurrentText(tunable.current)
+        combo.setCursor(Qt.CursorShape.PointingHandCursor)
+        apply_btn = QPushButton("Apply")
+        apply_btn.setObjectName("ActionButton")
+        apply_btn.setCursor(Qt.CursorShape.PointingHandCursor)
+        apply_btn.clicked.connect(lambda: on_apply(tunable.id, combo.currentText()))
+        row.addWidget(name)
+        row.addWidget(combo, 1)
+        row.addWidget(apply_btn)
+        v.addLayout(row)
+        if tunable.note:
+            note = QLabel(tunable.note)
+            note.setObjectName("Muted")
+            v.addWidget(note)
     return card
 
 
+def _tunable(finding):
+    """The runtime tunable a finding can apply, if any."""
+    fix = getattr(finding, "fix", "")
+    if not fix:
+        return None
+    from ..core import fixes
+
+    return fixes.get_tunable(fix)
+
+
+def _installable_component(finding):
+    """The catalog component a finding offers to install, if any and if apt is usable."""
+    action = getattr(finding, "action", "")
+    if not action:
+        return None
+    from ..core import catalog, sysenv
+
+    if sysenv.package_manager() != "apt":
+        return None  # apt-only (D15) — no one-click install elsewhere
+    return catalog.by_id(action)
+
+
 class Card(QFrame):
     """A titled panel whose body collapses when the header is clicked."""
 

tests/test_diagnostic.py

@@ -0,0 +1,61 @@
+"""Tests for the guided diagnostic orchestration (M3+M4 glue)."""
+
+import tempfile
+import time
+import unittest
+from pathlib import Path
+from unittest import mock
+
+from rigdoctor.core import diagnostic
+from rigdoctor.core.crashlog import CrashLogWriter, summarize
+from rigdoctor.core.health import Finding
+from rigdoctor.core.sample import Reading, Sample
+
+
+def _write_log(path: str, game: str) -> None:
+    w = CrashLogWriter(path)
+    w.write_event("session-start", "interval=1s")
+    w.write_event("game", game)
+    for temp in (60.0, 72.0, 81.0):
+        w.write_sample(Sample(ts=time.time(), readings=[Reading("gpu", "temp", temp, "°C", "")]))
+    w.write_event("gpu-lost", "nvidia-smi query timed out")
+    w.close()
+
+
+class GameRecoveryTests(unittest.TestCase):
+    def test_game_recovered_from_log_event(self):
+        with tempfile.TemporaryDirectory() as d:
+            log = str(Path(d) / "capture.jsonl")
+            _write_log(log, "Path of Exile 2")
+            summary = summarize(log)
+            self.assertEqual(diagnostic._game_from_summary(summary), "Path of Exile 2")
+
+    def test_no_game_event_returns_none(self):
+        with tempfile.TemporaryDirectory() as d:
+            log = str(Path(d) / "capture.jsonl")
+            w = CrashLogWriter(log)
+            w.write_event("session-start")
+            w.close()
+            self.assertIsNone(diagnostic._game_from_summary(summarize(log)))
+
+
+class FinishTests(unittest.TestCase):
+    def test_finish_combines_summary_and_findings(self):
+        with tempfile.TemporaryDirectory() as d:
+            log = Path(d) / "capture.jsonl"
+            _write_log(str(log), "Satisfactory")
+            fake = [Finding("warning", "GPU", "NVIDIA Xid 79 ×1", "fell off the bus")]
+            with mock.patch("rigdoctor.core.health.run_health_checks", return_value=fake), \
+                 mock.patch.object(diagnostic.reccontrol, "stop_background", return_value=False), \
+                 mock.patch.object(diagnostic.reccontrol, "running_pid", return_value=None):
+                result = diagnostic.finish(log_path=log)
+            self.assertEqual(result.game, "Satisfactory")
+            self.assertEqual(result.summary.samples, 3)
+            self.assertEqual(result.findings, fake)
+            # peak GPU temp captured in the window, GPU-lost event recorded
+            self.assertEqual(result.summary.maxima["gpu.temp"][0], 81.0)
+            self.assertTrue(any(kind == "gpu-lost" for _ts, kind, _d in result.summary.events))
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_fixes.py

@@ -0,0 +1,63 @@
+"""Tests for M6 runtime tunables (parse, command builders, value validation)."""
+
+import unittest
+from unittest import mock
+
+from rigdoctor.core import fixes
+from rigdoctor.core.fixes import Tunable
+
+
+class ParseTests(unittest.TestCase):
+    def test_bracketed(self):
+        self.assertEqual(fixes._bracketed("always [madvise] never"), (["always", "madvise", "never"], "madvise"))
+
+    def test_bracketed_none_active(self):
+        self.assertEqual(fixes._bracketed("a b c"), (["a", "b", "c"], None))
+
+
+class CommandBuilderTests(unittest.TestCase):
+    def test_governor_cmd_writes_value_to_sysfs(self):
+        cmd = fixes._cpu_governor_cmd("performance")
+        self.assertEqual(cmd[:2], ["/bin/sh", "-c"])
+        self.assertIn("performance", cmd[2])
+        self.assertIn("scaling_governor", cmd[2])
+
+    def test_persistence_cmd(self):
+        self.assertEqual(fixes._nvidia_persistence_cmd("Enabled"), ["nvidia-smi", "-pm", "1"])
+        self.assertEqual(fixes._nvidia_persistence_cmd("Disabled"), ["nvidia-smi", "-pm", "0"])
+
+    def test_swappiness_cmd_targets_procfs(self):
+        self.assertIn("/proc/sys/vm/swappiness", fixes._swappiness_cmd("10")[2])
+
+    def test_quoting_is_safe(self):
+        # A value that would be dangerous unquoted stays a single quoted token.
+        cmd = fixes._pcie_aspm_cmd("performance; rm -rf /")
+        self.assertIn("'performance; rm -rf /'", cmd[2])
+
+
+class ApplyValidationTests(unittest.TestCase):
+    def test_unknown_fix_returns_none(self):
+        self.assertIsNone(fixes.apply_command("does_not_exist", "x"))
+
+    def test_value_validated_against_live_options(self):
+        fake = Tunable("x", "X", ["a", "b"], "a")
+        with mock.patch.dict(fixes._TUNABLES, {"x": (lambda: fake, lambda v: ["echo", v])}, clear=False):
+            self.assertEqual(fixes.apply_command("x", "a"), ["echo", "a"])
+            self.assertIsNone(fixes.apply_command("x", "not-an-option"))
+
+    def test_apply_unknown_is_error(self):
+        rc, _ = fixes.apply("nope", "x")
+        self.assertEqual(rc, 1)
+
+
+class GameenvWiringTests(unittest.TestCase):
+    def test_findings_reference_known_fix_ids(self):
+        from rigdoctor.core import gameenv
+
+        fix_ids = {f.fix for f in gameenv.run_gameenv_checks() if f.fix}
+        # Whatever fixes the live system surfaces, each must be a real tunable id.
+        self.assertTrue(fix_ids.issubset(set(fixes._TUNABLES)))
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_gameenv.py

@@ -30,7 +30,7 @@ class GovernorTests(unittest.TestCase):
     def test_powersave_is_warning(self):
         f = gameenv.evaluate_governor({"powersave"})
         self.assertEqual(f.severity, "warning")
-        self.assertIn("cpupower", f.suggestion)
+        self.assertEqual(f.fix, "cpu_governor")  # offers the live Apply dropdown
 
     def test_dynamic_is_info(self):
         self.assertEqual(gameenv.evaluate_governor({"schedutil"}).severity, "info")
@@ -43,7 +43,7 @@ class SwappinessTests(unittest.TestCase):
     def test_high_is_info_with_suggestion(self):
         f = gameenv.evaluate_swappiness(60)
         self.assertEqual(f.severity, "info")
-        self.assertIn("swappiness", f.suggestion)
+        self.assertEqual(f.fix, "swappiness")  # offers the live Apply dropdown
 
     def test_low_is_ok(self):
         self.assertEqual(gameenv.evaluate_swappiness(10).severity, "ok")