Add isolated transport broker

README.md

@@ -21,8 +21,8 @@ capabilities they exercise, while project-specific target notes stay in private
 - Prompt on first visit before installing or starting a missing transport.
 - Manage approved transports through isolated AMPB state.
 - Keep browser profiles isolated by transport.
-- Treat route-aware desktop launches as a convenience and QA mode until storage isolation
-  is proven for mixed clearnet, Tor, and I2P navigation.
+- Hand alternate-network links from the clearnet broker to transport-specific browser
+  profiles before the destination request leaves the broker profile.
 - Present transport health in plain language.
 
 ## Non-goals
@@ -41,7 +41,7 @@ python3 -m ampbrowser route ipfs://bafyexample/
 python3 -m ampbrowser inspect
 python3 -m ampbrowser plan gemini://wownero.org/
 python3 -m ampbrowser open https://wownero.org/
-python3 -m ampbrowser open https://ampgateway.site/ --route-aware --launch
+python3 -m ampbrowser open https://ampgateway.site/ --broker --launch
 python3 -m ampbrowser open http://example.onion/ --launch
 python3 -m ampbrowser open http://example.onion/ --yes --launch
 python3 -m ampbrowser shell http://example.onion/
@@ -67,6 +67,7 @@ python3 -m unittest discover -s tests
 
 - [Architecture](docs/architecture.md)
 - [Browser builds](docs/browser-builds.md)
+- [Transport broker](docs/broker.md)
 - [Candidate transports](docs/candidate-transports.md)
 - [Configuration](docs/configuration.md)
 - [Desktop vertical](docs/desktop-vertical.md)

ampbrowser/broker.py

@@ -0,0 +1,41 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from .config import AppConfig
+from .launch import OpenPlan, prepare_open
+from .open_runner import launch_open_plan
+from .routing import route_url
+
+
+BROKER_TRANSPORTS = {"tor", "i2p"}
+
+
+class BrokerRouteError(ValueError):
+    pass
+
+
+def open_brokered_url(
+    raw_url: str,
+    *,
+    expected_transport: str,
+    consent: bool,
+    config: AppConfig,
+    root: Path,
+) -> OpenPlan:
+    route = route_url(raw_url)
+    if route.transport != expected_transport:
+        raise BrokerRouteError(
+            f"route transport {route.transport} does not match requested transport {expected_transport}"
+        )
+    if route.transport not in BROKER_TRANSPORTS:
+        raise BrokerRouteError(f"{route.transport} is not supported by the desktop broker yet")
+
+    open_plan = prepare_open(
+        route.normalized,
+        consent=consent,
+        dry_run=False,
+        config=config,
+        platform="desktop",
+    )
+    return launch_open_plan(open_plan, config=config, root=root)

ampbrowser/cli.py

@@ -41,9 +41,11 @@ def main(argv: list[str] | None = None) -> int:
         help="Approve first-use setup in the dry-run plan.",
     )
     open_parser.add_argument(
+        "--broker",
         "--route-aware",
+        dest="broker",
         action="store_true",
-        help="Launch one desktop profile with PAC routing for clearnet, Tor, and I2P.",
+        help="Launch a clearnet broker that hands Tor and I2P routes to isolated profiles.",
     )
     open_mode = open_parser.add_mutually_exclusive_group()
     open_mode.add_argument(
@@ -66,6 +68,11 @@ def main(argv: list[str] | None = None) -> int:
         action="store_true",
         help="Approve first-use setup without showing a prompt.",
     )
+    shell_parser.add_argument(
+        "--broker",
+        action="store_true",
+        help="Launch the isolated transport broker in the bundled browser.",
+    )
 
     subcommands.add_parser("inspect", help="Inspect local transport readiness.")
 
@@ -116,10 +123,10 @@ def main(argv: list[str] | None = None) -> int:
                 launch=args.launch,
                 config_path=args.config,
                 platform=args.platform,
-                route_aware=args.route_aware,
+                broker=args.broker,
             )
         if args.command == "shell":
-            return _cmd_shell(args.url, approve=args.yes, config_path=args.config)
+            return _cmd_shell(args.url, approve=args.yes, broker=args.broker, config_path=args.config)
         if args.command == "inspect":
             return _cmd_inspect()
         if args.command == "transport":
@@ -182,7 +189,7 @@ def _cmd_open(
     launch: bool,
     config_path: Path | None,
     platform: str | None,
-    route_aware: bool,
+    broker: bool,
 ) -> int:
     config = load_config(Path.cwd(), config_path)
     open_plan = prepare_open(
@@ -191,7 +198,7 @@ def _cmd_open(
         dry_run=dry_run,
         config=config,
         platform=platform,
-        route_aware=route_aware,
+        broker=broker,
     )
     if launch:
         open_plan = launch_open_plan(open_plan, config=config, root=Path.cwd())
@@ -199,9 +206,9 @@ def _cmd_open(
     return 0
 
 
-def _cmd_shell(url: str, *, approve: bool, config_path: Path | None) -> int:
+def _cmd_shell(url: str, *, approve: bool, broker: bool, config_path: Path | None) -> int:
     config = load_config(Path.cwd(), config_path)
-    result = launch_desktop_shell(url, config=config, root=Path.cwd(), auto_approve=approve)
+    result = launch_desktop_shell(url, config=config, root=Path.cwd(), auto_approve=approve, broker=broker)
     _print_open_plan(
         "AMPBROWSER_SHELL",
         result.open_plan,
@@ -220,8 +227,7 @@ def _print_open_plan(prefix: str, open_plan, extra_fields: tuple[str, ...] = ())
     launch_command = shlex.join(launch_spec.command) if launch_spec else "-"
     runtime_path = launch_spec.runtime_path if launch_spec else "-"
     user_js_path = launch_spec.user_js_path if launch_spec else "-"
-    route_aware = str(bool(launch_spec and launch_spec.route_aware)).lower()
-    pac_path = launch_spec.pac_path if launch_spec else "-"
+    broker = str(open_plan.broker).lower()
     message = _safe(open_plan.message)
     extra = (" " + " ".join(extra_fields)) if extra_fields else ""
     print(
@@ -240,10 +246,9 @@ def _print_open_plan(prefix: str, open_plan, extra_fields: tuple[str, ...] = ())
         f"browser_pid={open_plan.browser_pid} "
         f"profile_path={open_plan.profile_path} "
         f"proxy={open_plan.proxy} "
-        f"route_aware={route_aware} "
+        f"broker={broker} "
         f"runtime_path={runtime_path} "
         f"user_js_path={user_js_path} "
-        f"pac_path={pac_path} "
         f"setup_prompt_title=\"{_safe(open_plan.setup_prompt_title)}\" "
         f"setup_prompt_body=\"{_safe(open_plan.setup_prompt_body)}\" "
         f"setup_prompt_approve_label=\"{_safe(open_plan.setup_prompt_approve_label)}\" "
@@ -351,6 +356,8 @@ def _cmd_fixture(args) -> int:
                 f"actual_transport={check.actual_transport} "
                 f"expected_profile={check.expected_profile} "
                 f"actual_profile={check.actual_profile} "
+                f"expected_isolation={check.expected_isolation} "
+                f"actual_isolation={check.actual_isolation} "
                 f"tier={check.tier} "
                 f"identity={check.identity} "
                 f"payments={check.payments} "

ampbrowser/config.py

@@ -22,6 +22,7 @@ class ConfigError(ValueError):
 
 @dataclass(frozen=True)
 class AppConfig:
+    config_path: str = ""
     state_dir: str = ".ampb"
     default_engine: str = "ampb-gecko"
     runtime_path: str = ""
@@ -82,6 +83,7 @@ def _parse_config(data: dict[str, Any], path: Path) -> AppConfig:
     transport_binaries = _transport_binaries(transports, path)
 
     return AppConfig(
+        config_path=str(path.resolve()),
         state_dir=state_dir,
         default_engine=default_engine,
         runtime_path=runtime_path,

ampbrowser/desktop_shell.py

@@ -27,9 +27,17 @@ def launch_desktop_shell(
     config: AppConfig,
     root: Path,
     auto_approve: bool = False,
+    broker: bool = False,
     prompt_driver: PromptDriver | None = None,
 ) -> DesktopShellResult:
-    open_plan = prepare_open(raw_url, consent=False, dry_run=False, config=config, platform="desktop")
+    open_plan = prepare_open(
+        raw_url,
+        consent=False,
+        dry_run=False,
+        config=config,
+        platform="desktop",
+        broker=broker,
+    )
     prompt_shown = False
     prompt_approved = False
 
@@ -45,7 +53,14 @@ def launch_desktop_shell(
                 prompt_shown,
                 False,
             )
-        open_plan = prepare_open(raw_url, consent=True, dry_run=False, config=config, platform="desktop")
+        open_plan = prepare_open(
+            raw_url,
+            consent=True,
+            dry_run=False,
+            config=config,
+            platform="desktop",
+            broker=broker,
+        )
 
     return DesktopShellResult(
         launch_open_plan(open_plan, config=config, root=root),

ampbrowser/fixtures.py

@@ -23,6 +23,8 @@ class FixtureCheck:
     actual_transport: str
     expected_profile: str
     actual_profile: str
+    expected_isolation: str
+    actual_isolation: str
     tier: str
     identity: str
     payments: str
@@ -78,15 +80,19 @@ def _check_fixture(site_id: str, fixture: Any, path: Path) -> FixtureCheck:
         raise ValueError(f"{path}: {protocol}: missing checks table")
     expected_transport = _string(checks, "transport")
     expected_profile = _string(checks, "profile")
+    expected_isolation = _optional_string(checks, "isolation", "transport-profile")
     interaction = _interaction_policy(fixture)
     route_metadata = _route_metadata(fixture)
 
     route = route_url(url)
+    actual_isolation = "transport-profile" if route.profile == route.transport else "shared-profile"
     failures: list[str] = []
     if route.transport != expected_transport:
         failures.append(f"transport expected {expected_transport} got {route.transport}")
     if route.profile != expected_profile:
         failures.append(f"profile expected {expected_profile} got {route.profile}")
+    if actual_isolation != expected_isolation:
+        failures.append(f"isolation expected {expected_isolation} got {actual_isolation}")
     failures.extend(
         interaction_failures(
             expected_transport,
@@ -108,6 +114,8 @@ def _check_fixture(site_id: str, fixture: Any, path: Path) -> FixtureCheck:
         actual_transport=route.transport,
         expected_profile=expected_profile,
         actual_profile=route.profile,
+        expected_isolation=expected_isolation,
+        actual_isolation=actual_isolation,
         tier=interaction["tier"],
         identity=interaction["identity"],
         payments=interaction["payments"],

ampbrowser/launch.py

@@ -19,12 +19,11 @@ from .config import AppConfig, default_config
 from .plan import BrowsePlan, plan_url
 
 
-ROUTE_AWARE_PROFILE = "route-aware"
-ROUTE_AWARE_PAC_NAME = "ampb-proxy.pac"
+BROKER_PROFILE = "broker"
 ROUTE_HELPER_EXTENSION_ID = "ampb-route-helper@such.software"
-PAC_URL_PLACEHOLDER = "__AMPB_ROUTE_AWARE_PAC_URL__"
 HELPER_URL_PLACEHOLDER = "__AMPB_ROUTE_HELPER_URL__"
 HELPER_TOKEN_PLACEHOLDER = "__AMPB_ROUTE_HELPER_TOKEN__"
+PROFILE_SESSION_NAME = "ampb-session.json"
 
 
 @dataclass(frozen=True)
@@ -51,9 +50,7 @@ class BrowserLaunchSpec:
     user_js_path: str
     command: tuple[str, ...]
     prefs: tuple[str, ...]
-    route_aware: bool = False
-    pac_path: str = "-"
-    pac_content: str = ""
+    broker: bool = False
     extension_path: str = "-"
     extension_assets: tuple[ProfileAsset, ...] = ()
 
@@ -68,6 +65,7 @@ class OpenPlan:
     proxy: str
     setup_steps: tuple[str, ...]
     message: str
+    broker: bool = False
     launch_spec: BrowserLaunchSpec | None = None
     browser_pid: int = 0
     setup_prompt_title: str = "-"
@@ -94,18 +92,32 @@ def prepare_open(
     dry_run: bool = True,
     config: AppConfig | None = None,
     platform: str | None = None,
+    broker: bool = False,
     route_aware: bool = False,
 ) -> OpenPlan:
     config = config or default_config()
     browse_plan = plan_url(raw_url, config=config, platform=platform)
+    broker = broker or route_aware
+    if broker and browse_plan.route.transport != "clearnet":
+        return OpenPlan(
+            browse_plan=browse_plan,
+            status="blocked",
+            dry_run=dry_run,
+            consent_granted=consent,
+            profile_path=config.profile_path(BROKER_PROFILE),
+            proxy="-",
+            setup_steps=(),
+            message="broker entry URLs must use clearnet; alternate routes open in their isolated profile",
+            broker=True,
+        )
     profile_name = (
-        ROUTE_AWARE_PROFILE
-        if route_aware and browse_plan.route.transport in {"clearnet", "tor", "i2p"}
+        BROKER_PROFILE
+        if broker
         else browse_plan.route.profile
     )
     profile_path = config.profile_path(profile_name)
     proxy = _proxy_for(browse_plan)
-    launch_spec = _launch_spec_for(browse_plan, config=config, profile_path=profile_path, route_aware=route_aware)
+    launch_spec = _launch_spec_for(browse_plan, config=config, profile_path=profile_path, broker=broker)
 
     if browse_plan.action.startswith("blocked"):
         return OpenPlan(
@@ -117,12 +129,13 @@ def prepare_open(
             proxy=proxy,
             setup_steps=(),
             message=browse_plan.action,
+            broker=broker,
             launch_spec=launch_spec,
         )
 
     if browse_plan.requires_consent:
         setup_steps = _setup_steps(browse_plan)
-        setup_prompt = _setup_prompt(browse_plan, setup_steps, route_aware=route_aware)
+        setup_prompt = _setup_prompt(browse_plan, setup_steps)
         if not consent:
             return OpenPlan(
                 browse_plan=browse_plan,
@@ -133,6 +146,7 @@ def prepare_open(
                 proxy=proxy,
                 setup_steps=setup_steps,
                 message=browse_plan.prompt,
+                broker=broker,
                 launch_spec=launch_spec,
                 setup_prompt_title=setup_prompt.title,
                 setup_prompt_body=setup_prompt.body,
@@ -148,6 +162,7 @@ def prepare_open(
             proxy=proxy,
             setup_steps=setup_steps,
             message="first-use setup approved; browser launch waits for transport readiness",
+            broker=broker,
             launch_spec=launch_spec,
             setup_prompt_title=setup_prompt.title,
             setup_prompt_body=setup_prompt.body,
@@ -164,11 +179,17 @@ def prepare_open(
         proxy=proxy,
         setup_steps=(),
         message="ready to open with isolated profile",
+        broker=broker,
         launch_spec=launch_spec,
     )
 
 
-def execute_open(open_plan: OpenPlan, *, root: Path | None = None) -> OpenPlan:
+def execute_open(
+    open_plan: OpenPlan,
+    *,
+    root: Path | None = None,
+    config: AppConfig | None = None,
+) -> OpenPlan:
     root = root or Path.cwd()
     spec = open_plan.launch_spec
     if spec is None:
@@ -194,17 +215,31 @@ def execute_open(open_plan: OpenPlan, *, root: Path | None = None) -> OpenPlan:
             message=f"browser runtime not found: {spec.runtime_path}",
         )
 
-    route_helper = _route_helper_launch_plan(root) if spec.route_aware else RouteHelperLaunch("disabled")
+    active_pid = _active_profile_session(root, spec)
+    if active_pid:
+        return _open_existing_profile(open_plan, root=root, spec=spec, active_pid=active_pid)
+
+    config_path = Path(config.config_path) if config and config.config_path else None
+    route_helper = (
+        _route_helper_launch_plan(root, config_path=config_path)
+        if spec.broker
+        else RouteHelperLaunch("disabled")
+    )
     _write_profile(root, spec, route_helper=route_helper)
     launch_spec = replace(spec, command=_execution_command(root, spec))
     process = subprocess.Popen(launch_spec.command, cwd=str(root), start_new_session=True)  # noqa: S603
-    if spec.route_aware:
-        route_helper = _start_route_helper(root, planned=route_helper, watch_pid=process.pid)
+    if spec.broker:
+        route_helper = _start_route_helper(
+            root,
+            planned=route_helper,
+            watch_pid=process.pid,
+            config_path=config_path,
+        )
     exit_code = _immediate_exit_code(process)
     if exit_code is not None:
         helper_status = route_helper.status
         helper_message = route_helper.message
-        if spec.route_aware:
+        if spec.broker:
             helper_status = _stop_route_helper(route_helper)
             helper_message = "stopped route helper after browser exited immediately"
         return replace(
@@ -219,9 +254,10 @@ def execute_open(open_plan: OpenPlan, *, root: Path | None = None) -> OpenPlan:
             route_helper_pid=route_helper.pid,
             route_helper_message=helper_message,
         )
+    _record_profile_session(root, spec, process.pid)
     message = "launched bundled browser"
-    if spec.route_aware:
-        message = f"launched bundled browser with route helper {route_helper.status}"
+    if spec.broker:
+        message = f"launched isolated transport broker with route helper {route_helper.status}"
     return replace(
         open_plan,
         dry_run=False,
@@ -274,7 +310,7 @@ class _SetupPrompt:
     approval_command: str
 
 
-def _setup_prompt(browse_plan: BrowsePlan, setup_steps: tuple[str, ...], *, route_aware: bool = False) -> _SetupPrompt:
+def _setup_prompt(browse_plan: BrowsePlan, setup_steps: tuple[str, ...]) -> _SetupPrompt:
     transport = browse_plan.route.transport
     label = _transport_label(transport)
     platform = browse_plan.platform_capability.platform
@@ -297,8 +333,6 @@ def _setup_prompt(browse_plan: BrowsePlan, setup_steps: tuple[str, ...], *, rout
         f"{browse_plan.route.normalized}. Setup plan: {setup_summary}."
     )
     approval_args = ["ampbrowser", "open", browse_plan.route.normalized, "--yes", "--launch"]
-    if route_aware:
-        approval_args.append("--route-aware")
     approval_command = shlex.join(approval_args)
     return _SetupPrompt(
         title=f"Set up {label}?",
@@ -324,27 +358,23 @@ def _launch_spec_for(
     *,
     config: AppConfig,
     profile_path: str,
-    route_aware: bool = False,
+    broker: bool = False,
 ) -> BrowserLaunchSpec | None:
     if browse_plan.route.transport not in {"clearnet", "tor", "i2p"}:
         return None
     runtime_path = _runtime_path(config)
     user_js_path = str(Path(profile_path) / "user.js")
     command = (runtime_path, "--new-instance", "--profile", profile_path, browse_plan.route.normalized)
-    prefs = _prefs_for(browse_plan, route_aware=route_aware)
-    pac_path = str(Path(profile_path) / ROUTE_AWARE_PAC_NAME) if route_aware else "-"
-    pac_content = _route_aware_pac() if route_aware else ""
-    extension_path = str(Path(profile_path) / "extensions" / ROUTE_HELPER_EXTENSION_ID) if route_aware else "-"
-    extension_assets = _route_helper_extension_assets(extension_path) if route_aware else ()
+    prefs = _prefs_for(browse_plan, broker=broker)
+    extension_path = str(Path(profile_path) / "extensions" / ROUTE_HELPER_EXTENSION_ID) if broker else "-"
+    extension_assets = _route_helper_extension_assets(extension_path) if broker else ()
     return BrowserLaunchSpec(
         runtime_path=runtime_path,
         profile_path=profile_path,
         user_js_path=user_js_path,
         command=command,
         prefs=prefs,
-        route_aware=route_aware,
-        pac_path=pac_path,
-        pac_content=pac_content,
+        broker=broker,
         extension_path=extension_path,
         extension_assets=extension_assets,
     )
@@ -372,7 +402,7 @@ def _runtime_candidates(build_root: Path) -> tuple[Path, ...]:
     )
 
 
-def _prefs_for(browse_plan: BrowsePlan, *, route_aware: bool = False) -> tuple[str, ...]:
+def _prefs_for(browse_plan: BrowsePlan, *, broker: bool = False) -> tuple[str, ...]:
     prefs: list[tuple[str, str | int | bool]] = [
         ("browser.shell.checkDefaultBrowser", False),
         ("datareporting.policy.dataSubmissionEnabled", False),
@@ -381,14 +411,10 @@ def _prefs_for(browse_plan: BrowsePlan, *, route_aware: bool = False) -> tuple[s
         ("network.predictor.enabled", False),
     ]
 
-    if route_aware:
+    if broker:
         prefs.extend(
             [
-                ("network.proxy.type", 2),
-                ("network.proxy.autoconfig_url", PAC_URL_PLACEHOLDER),
-                ("network.proxy.failover_direct", False),
-                ("network.proxy.socks_remote_dns", True),
-                ("network.proxy.no_proxies_on", ""),
+                ("network.proxy.type", 0),
                 ("extensions.autoDisableScopes", 0),
                 ("extensions.enabledScopes", 5),
                 ("xpinstall.signatures.required", False),
@@ -427,52 +453,6 @@ def _prefs_for(browse_plan: BrowsePlan, *, route_aware: bool = False) -> tuple[s
     return tuple(_format_pref(name, value) for name, value in prefs)
 
 
-def _route_aware_pac() -> str:
-    tor_proxy = _pac_proxy_for_endpoint(
-        "SOCKS5",
-        _endpoint_for_transport("tor", "socks5://127.0.0.1:9050"),
-    )
-    i2p_proxy = _pac_proxy_for_endpoint(
-        "PROXY",
-        _endpoint_for_transport("i2p", "http://127.0.0.1:4444"),
-    )
-    return "\n".join(
-        (
-            "// Managed by AMPB. Route-aware proxy policy.",
-            "function hasSuffix(value, suffix) {",
-            "  return value.length >= suffix.length && value.substring(value.length - suffix.length) === suffix;",
-            "}",
-            "",
-            "function FindProxyForURL(url, host) {",
-            '  var h = (host || "").toLowerCase();',
-            '  if (h.length > 0 && h.charAt(h.length - 1) === ".") {',
-            "    h = h.substring(0, h.length - 1);",
-            "  }",
-            '  if (hasSuffix(h, ".onion")) {',
-            f'    return "{tor_proxy}";',
-            "  }",
-            '  if (hasSuffix(h, ".i2p")) {',
-            f'    return "{i2p_proxy}";',
-            "  }",
-            '  return "DIRECT";',
-            "}",
-            "",
-        )
-    )
-
-
-def _endpoint_for_transport(transport: str, fallback: str) -> str:
-    adapter = adapter_for(transport)
-    if adapter:
-        return adapter.endpoint
-    return fallback
-
-
-def _pac_proxy_for_endpoint(proxy_type: str, endpoint: str) -> str:
-    host, port = _endpoint_host_port(endpoint)
-    return f"{proxy_type} {host}:{port}"
-
-
 def _route_helper_extension_assets(extension_path: str) -> tuple[ProfileAsset, ...]:
     base = Path(extension_path)
     return (
@@ -481,6 +461,8 @@ def _route_helper_extension_assets(extension_path: str) -> tuple[ProfileAsset, .
         ProfileAsset(str(base / "setup.html"), _route_helper_setup_html()),
         ProfileAsset(str(base / "setup.js"), _route_helper_setup_js()),
         ProfileAsset(str(base / "setup.css"), _route_helper_setup_css()),
+        ProfileAsset(str(base / "handoff.html"), _route_helper_handoff_html()),
+        ProfileAsset(str(base / "handoff.js"), _route_helper_handoff_js()),
     )
 
 
@@ -490,11 +472,20 @@ def _route_helper_manifest() -> str:
             "manifest_version": 2,
             "name": "AMPB Route Helper",
             "version": "0.1.0",
-            "description": "Starts AMPB-managed transports when alternate-network links are opened.",
+            "description": "Hands alternate-network links to isolated AMPB transport profiles.",
             "applications": {"gecko": {"id": ROUTE_HELPER_EXTENSION_ID}},
             "permissions": [
                 "tabs",
-                "webNavigation",
+                "webRequest",
+                "webRequestBlocking",
+                "http://*.onion/*",
+                "https://*.onion/*",
+                "ws://*.onion/*",
+                "wss://*.onion/*",
+                "http://*.i2p/*",
+                "https://*.i2p/*",
+                "ws://*.i2p/*",
+                "wss://*.i2p/*",
                 "http://127.0.0.1/*",
             ],
             "background": {"scripts": ["background.js"]},
@@ -523,44 +514,64 @@ def _route_helper_background_js() -> str:
             "  return '';",
             "}",
             "",
-            "async function helper(action, transport, url) {",
+            "async function helper(action, transport, url, consent = false) {",
             "  const response = await fetch(HELPER_URL, {",
             "    method: 'POST',",
             "    headers: {",
             "      'Content-Type': 'application/json',",
             "      'X-AMPB-Token': HELPER_TOKEN,",
             "    },",
-            "    body: JSON.stringify({ action, transport, url }),",
+            "    body: JSON.stringify({ action, transport, url, consent }),",
             "  });",
             "  return response.json();",
             "}",
             "",
-            "async function handleNavigate(details) {",
-            "  if (details.frameId !== 0) return;",
-            "  const transport = transportForUrl(details.url);",
-            "  if (!transport) return;",
-            "  const key = `${details.tabId}:${details.url}`;",
-            "  if (pendingByTab.get(details.tabId) === details.url) return;",
-            "  let status;",
-            "  try {",
-            "    status = await helper('status', transport, details.url);",
-            "  } catch (error) {",
-            "    status = { ok: false, ready: false, message: String(error) };",
-            "  }",
-            "  if (status.ready) return;",
-            "  pendingByTab.set(details.tabId, details.url);",
-            "  const installCommand = Array.isArray(status.install_command) ? status.install_command.join(' ') : '';",
-            "  const setupUrl = browser.runtime.getURL(",
-            "    `setup.html?transport=${encodeURIComponent(transport)}&url=${encodeURIComponent(details.url)}&message=${encodeURIComponent(status.message || '')}&hint=${encodeURIComponent(status.setup_hint || '')}&install=${encodeURIComponent(installCommand)}`",
-            "  );",
-            "  await browser.tabs.update(details.tabId, { url: setupUrl });",
+            "function internalUrl(page, transport, url, result) {",
+            "  const installCommand = Array.isArray(result.install_command) ? result.install_command.join(' ') : '';",
+            "  const params = new URLSearchParams({",
+            "    transport,",
+            "    url,",
+            "    message: result.message || '',",
+            "    hint: result.setup_hint || '',",
+            "    install: installCommand,",
+            "  });",
+            "  return browser.runtime.getURL(`${page}.html?${params.toString()}`);",
             "}",
             "",
-            "browser.webNavigation.onBeforeNavigate.addListener(handleNavigate);",
+            "async function handoff(details, transport) {",
+            "  let result;",
+            "  try {",
+            "    result = await helper('open', transport, details.url, false);",
+            "  } catch (error) {",
+            "    result = { ok: false, launched: false, message: String(error) };",
+            "  }",
+            "  const page = result.launched ? 'handoff' : 'setup';",
+            "  try {",
+            "    await browser.tabs.update(details.tabId, { url: internalUrl(page, transport, details.url, result) });",
+            "  } finally {",
+            "    pendingByTab.delete(details.tabId);",
+            "  }",
+            "}",
+            "",
+            "function interceptRequest(details) {",
+            "  const transport = transportForUrl(details.url);",
+            "  if (!transport) return {};",
+            "  if (details.type !== 'main_frame' || details.tabId < 0) return { cancel: true };",
+            "  if (pendingByTab.get(details.tabId) === details.url) return { cancel: true };",
+            "  pendingByTab.set(details.tabId, details.url);",
+            "  void handoff(details, transport);",
+            "  return { cancel: true };",
+            "}",
+            "",
+            "browser.webRequest.onBeforeRequest.addListener(",
+            "  interceptRequest,",
+            "  { urls: ['http://*.onion/*', 'https://*.onion/*', 'ws://*.onion/*', 'wss://*.onion/*', 'http://*.i2p/*', 'https://*.i2p/*', 'ws://*.i2p/*', 'wss://*.i2p/*'] },",
+            "  ['blocking']",
+            ");",
             "",
             "browser.runtime.onMessage.addListener((message) => {",
-            "  if (!message || message.type !== 'ampb-ensure') return false;",
-            "  return helper('ensure', message.transport, message.url);",
+            "  if (!message || message.type !== 'ampb-open') return false;",
+            "  return helper('open', message.transport, message.url, message.consent === true);",
             "});",
             "",
         )
@@ -631,10 +642,11 @@ def _route_helper_setup_js() -> str:
             "document.getElementById('approve').addEventListener('click', async () => {",
             "  const status = document.getElementById('status');",
             "  status.textContent = `Starting ${label}...`;",
-            "  const result = await browser.runtime.sendMessage({ type: 'ampb-ensure', transport, url });",
-            "  if (result && result.ready) {",
-            "    status.textContent = `${label} is ready. Opening route...`;",
-            "    window.location.href = url;",
+            "  const result = await browser.runtime.sendMessage({ type: 'ampb-open', transport, url, consent: true });",
+            "  if (result && result.launched) {",
+            "    status.textContent = `${label} opened in its isolated browser profile.`;",
+            "    const params = new URLSearchParams({ transport, url });",
+            "    window.location.href = browser.runtime.getURL(`handoff.html?${params.toString()}`);",
             "    return;",
             "  }",
             "  if (result && Array.isArray(result.install_command)) {",
@@ -664,6 +676,49 @@ def _route_helper_setup_css() -> str:
     )
 
 
+def _route_helper_handoff_html() -> str:
+    return "\n".join(
+        (
+            "<!doctype html>",
+            '<html lang="en">',
+            "<head>",
+            '  <meta charset="utf-8">',
+            '  <meta name="viewport" content="width=device-width, initial-scale=1">',
+            "  <title>Route Opened</title>",
+            '  <link rel="stylesheet" href="setup.css">',
+            "</head>",
+            "<body>",
+            '  <main class="panel">',
+            '    <p class="eyebrow">AMPB Transport Broker</p>',
+            '    <h1 id="title">Route opened</h1>',
+            '    <p id="body">The destination is open in its isolated transport profile.</p>',
+            '    <pre id="url"></pre>',
+            "  </main>",
+            '  <script src="handoff.js"></script>',
+            "</body>",
+            "</html>",
+            "",
+        )
+    )
+
+
+def _route_helper_handoff_js() -> str:
+    return "\n".join(
+        (
+            '"use strict";',
+            "",
+            "const params = new URLSearchParams(window.location.search);",
+            "const transport = params.get('transport') || '';",
+            "const url = params.get('url') || '';",
+            "const label = transport === 'tor' ? 'Tor' : transport === 'i2p' ? 'I2P' : transport;",
+            "document.getElementById('title').textContent = `${label} route opened`;",
+            "document.getElementById('body').textContent = `This destination opened in the isolated ${label} profile. This clearnet profile did not load it.`;",
+            "document.getElementById('url').textContent = url;",
+            "",
+        )
+    )
+
+
 def _endpoint_host_port(endpoint: str) -> tuple[str, int]:
     parsed = urlparse(endpoint)
     return parsed.hostname or "127.0.0.1", parsed.port or 0
@@ -679,7 +734,7 @@ def _format_pref(name: str, value: str | int | bool) -> str:
     return f"user_pref({json.dumps(name)}, {literal});"
 
 
-def _route_helper_launch_plan(root: Path) -> RouteHelperLaunch:
+def _route_helper_launch_plan(root: Path, *, config_path: Path | None = None) -> RouteHelperLaunch:
     port = _free_loopback_port()
     token = secrets.token_urlsafe(24)
     endpoint = f"http://127.0.0.1:{port}/"
@@ -687,7 +742,7 @@ def _route_helper_launch_plan(root: Path) -> RouteHelperLaunch:
         "planned",
         endpoint=endpoint,
         token=token,
-        command=_route_helper_command(root=root, port=port, token=token),
+        command=_route_helper_command(root=root, port=port, token=token, config_path=config_path),
     )
 
 
@@ -696,10 +751,17 @@ def _start_route_helper(
     *,
     planned: RouteHelperLaunch | None = None,
     watch_pid: int = 0,
+    config_path: Path | None = None,
 ) -> RouteHelperLaunch:
-    helper = planned or _route_helper_launch_plan(root)
+    helper = planned or _route_helper_launch_plan(root, config_path=config_path)
     port = _endpoint_host_port(helper.endpoint)[1]
-    command = _route_helper_command(root=root, port=port, token=helper.token, watch_pid=watch_pid)
+    command = _route_helper_command(
+        root=root,
+        port=port,
+        token=helper.token,
+        watch_pid=watch_pid,
+        config_path=config_path,
+    )
     try:
         process = subprocess.Popen(command, cwd=str(root), start_new_session=True)  # noqa: S603
     except OSError as exc:
@@ -707,7 +769,14 @@ def _start_route_helper(
     return replace(helper, status="started", pid=process.pid, watch_pid=watch_pid, command=command, message="-")
 
 
-def _route_helper_command(*, root: Path, port: int, token: str, watch_pid: int = 0) -> tuple[str, ...]:
+def _route_helper_command(
+    *,
+    root: Path,
+    port: int,
+    token: str,
+    watch_pid: int = 0,
+    config_path: Path | None = None,
+) -> tuple[str, ...]:
     command = (
         sys.executable,
         "-m",
@@ -724,6 +793,8 @@ def _route_helper_command(*, root: Path, port: int, token: str, watch_pid: int =
     )
     if watch_pid > 0:
         command = (*command, "--watch-pid", str(watch_pid))
+    if config_path:
+        command = (*command, "--config", str(config_path))
     return command
 
 
@@ -739,6 +810,102 @@ def _execution_command(root: Path, spec: BrowserLaunchSpec) -> tuple[str, ...]:
     return tuple(command)
 
 
+def _open_existing_profile(
+    open_plan: OpenPlan,
+    *,
+    root: Path,
+    spec: BrowserLaunchSpec,
+    active_pid: int,
+) -> OpenPlan:
+    runtime_path = str(_path_from(root, spec.runtime_path))
+    profile_path = str(_path_from(root, spec.profile_path))
+    command = (runtime_path, "--profile", profile_path, "--new-tab", open_plan.browse_plan.route.normalized)
+    try:
+        process = subprocess.Popen(command, cwd=str(root), start_new_session=True)  # noqa: S603
+    except OSError as exc:
+        return replace(
+            open_plan,
+            dry_run=False,
+            status="profile-reuse-failed",
+            browser_pid=active_pid,
+            message=f"could not open route in active {open_plan.browse_plan.route.profile} profile: {exc}",
+        )
+    exit_code = _immediate_exit_code(process)
+    if exit_code == 0:
+        return replace(
+            open_plan,
+            dry_run=False,
+            launch_spec=replace(spec, command=command),
+            status="opened-existing",
+            browser_pid=active_pid,
+            message=f"opened route in active {open_plan.browse_plan.route.profile} profile",
+        )
+    if exit_code is None:
+        _record_profile_session(root, spec, process.pid)
+        return replace(
+            open_plan,
+            dry_run=False,
+            launch_spec=replace(spec, command=command),
+            status="launched",
+            browser_pid=process.pid,
+            message=f"launched replacement {open_plan.browse_plan.route.profile} profile process",
+        )
+    return replace(
+        open_plan,
+        dry_run=False,
+        launch_spec=replace(spec, command=command),
+        status="profile-reuse-failed",
+        browser_pid=active_pid,
+        message=f"active profile rejected route with code {exit_code}",
+    )
+
+
+def _active_profile_session(root: Path, spec: BrowserLaunchSpec) -> int:
+    session_path = _profile_session_path(root, spec)
+    try:
+        data = json.loads(session_path.read_text(encoding="utf-8"))
+    except (OSError, json.JSONDecodeError):
+        return 0
+    if not isinstance(data, dict):
+        return 0
+    pid = data.get("pid")
+    runtime_path = data.get("runtime_path")
+    if not isinstance(pid, int) or pid <= 0 or runtime_path != str(_path_from(root, spec.runtime_path)):
+        return 0
+    if _pid_exists(pid):
+        return pid
+    try:
+        session_path.unlink()
+    except OSError:
+        pass
+    return 0
+
+
+def _record_profile_session(root: Path, spec: BrowserLaunchSpec, pid: int) -> None:
+    if not isinstance(pid, int) or pid <= 0:
+        return
+    session_path = _profile_session_path(root, spec)
+    session_path.parent.mkdir(parents=True, exist_ok=True)
+    payload = {
+        "pid": pid,
+        "profile_path": str(_path_from(root, spec.profile_path)),
+        "runtime_path": str(_path_from(root, spec.runtime_path)),
+    }
+    temporary_path = session_path.with_name(f".{PROFILE_SESSION_NAME}.{pid}.tmp")
+    try:
+        temporary_path.write_text(json.dumps(payload, indent=2, sort_keys=True) + "\n", encoding="utf-8")
+        temporary_path.replace(session_path)
+    except OSError:
+        try:
+            temporary_path.unlink()
+        except OSError:
+            pass
+
+
+def _profile_session_path(root: Path, spec: BrowserLaunchSpec) -> Path:
+    return _path_from(root, spec.profile_path) / PROFILE_SESSION_NAME
+
+
 def _stop_route_helper(route_helper: RouteHelperLaunch) -> str:
     if route_helper.pid <= 0:
         return route_helper.status
@@ -757,6 +924,16 @@ def _immediate_exit_code(process: subprocess.Popen, *, wait_seconds: float = 1.0
     return None
 
 
+def _pid_exists(pid: int) -> bool:
+    if pid <= 0:
+        return False
+    try:
+        os.kill(pid, 0)
+    except OSError:
+        return False
+    return True
+
+
 def _free_loopback_port() -> int:
     with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
         sock.bind(("127.0.0.1", 0))
@@ -766,13 +943,7 @@ def _free_loopback_port() -> int:
 def _write_profile(root: Path, spec: BrowserLaunchSpec, *, route_helper: RouteHelperLaunch | None = None) -> None:
     profile_path = _path_from(root, spec.profile_path)
     profile_path.mkdir(parents=True, exist_ok=True)
-    pac_url = "-"
-    if spec.route_aware and spec.pac_content:
-        pac_path = _path_from(root, spec.pac_path)
-        pac_path.parent.mkdir(parents=True, exist_ok=True)
-        pac_path.write_text(spec.pac_content, encoding="utf-8")
-        pac_url = pac_path.resolve().as_uri()
-    if spec.route_aware:
+    if spec.broker:
         helper = route_helper or RouteHelperLaunch("disabled")
         for asset in spec.extension_assets:
             asset_path = _path_from(root, asset.path)
@@ -782,7 +953,6 @@ def _write_profile(root: Path, spec: BrowserLaunchSpec, *, route_helper: RouteHe
             asset_path.write_text(content, encoding="utf-8")
     user_js_path = _path_from(root, spec.user_js_path)
     text = "// Managed by AMPB. Local browser profile policy.\n" + "\n".join(spec.prefs) + "\n"
-    text = text.replace(PAC_URL_PLACEHOLDER, pac_url)
     user_js_path.write_text(text, encoding="utf-8")
 
 

ampbrowser/open_runner.py

@@ -29,4 +29,4 @@ def launch_open_plan(open_plan: OpenPlan, *, config: AppConfig, root: Path) -> O
             transport_setup_endpoint=transport_result.endpoint,
             transport_setup_message=transport_result.message,
         )
-    return execute_open(open_plan, root=root)
+    return execute_open(open_plan, root=root, config=config)

ampbrowser/route_helper.py

@@ -8,7 +8,9 @@ import threading
 import time
 from typing import Any
 
+from .broker import BrokerRouteError, open_brokered_url
 from .config import AppConfig, load_config
+from .launch import OpenPlan
 from .routing import route_url
 from .transport_manager import ManagedTransportResult, ensure_transport_ready, transport_status
 
@@ -33,6 +35,24 @@ def handle_helper_message(
         return _result_response(transport_status(transport, config=config, root=root))
     if action == "ensure":
         return _result_response(ensure_transport_ready(transport, config=config, root=root))
+    if action == "open":
+        raw_url = _string(message.get("url"))
+        if not raw_url:
+            return _error_response("missing-url", "broker open requires a URL")
+        try:
+            open_plan = open_brokered_url(
+                raw_url,
+                expected_transport=transport,
+                consent=message.get("consent") is True,
+                config=config,
+                root=root,
+            )
+        except BrokerRouteError as exc:
+            return _error_response("route-mismatch", str(exc))
+        transport_result = None
+        if open_plan.status not in {"launched", "opened-existing"}:
+            transport_result = transport_status(transport, config=config, root=root)
+        return _open_response(open_plan, transport_result)
     return _error_response("unsupported-action", f"unsupported helper action: {action or '-'}")
 
 
@@ -131,6 +151,32 @@ def _result_response(result: ManagedTransportResult) -> dict[str, Any]:
     }
 
 
+def _open_response(
+    open_plan: OpenPlan,
+    transport_result: ManagedTransportResult | None,
+) -> dict[str, Any]:
+    route = open_plan.browse_plan.route
+    opened = open_plan.status in {"launched", "opened-existing"}
+    return {
+        "ok": True,
+        "transport": route.transport,
+        "profile": route.profile,
+        "status": open_plan.status,
+        "ready": opened,
+        "launched": opened,
+        "requires_consent": open_plan.status == "consent-required",
+        "consent_granted": open_plan.consent_granted,
+        "browser_pid": open_plan.browser_pid,
+        "profile_path": open_plan.profile_path,
+        "message": open_plan.message,
+        "setup_prompt_title": open_plan.setup_prompt_title,
+        "setup_prompt_body": open_plan.setup_prompt_body,
+        "setup_prompt_approve_label": open_plan.setup_prompt_approve_label,
+        "setup_hint": transport_result.setup_hint if transport_result else "-",
+        "install_command": list(transport_result.install_command) if transport_result else [],
+    }
+
+
 def _error_response(status: str, message: str) -> dict[str, Any]:
     return {
         "ok": False,

docs/architecture.md

@@ -1,6 +1,6 @@
 # Architecture
 
-> Status: draft | Updated 2026-07-07 | Applies to: AMPB contributors and integrators
+> Status: draft | Updated 2026-07-11 | Applies to: AMPB contributors and integrators
 
 AMPB is a browser orchestration layer for privacy, resilient-network, content-addressed,
 and alternate-web transports. It keeps the routing, transport management, and profile
@@ -16,12 +16,20 @@ isolation decisions outside the browser engine until those contracts are stable.
 6. Start or install managed transports only after user consent.
 7. Open the URL with the matching isolated profile.
 
+The clearnet entry profile is a broker, not a mixed-network profile. It uses direct
+clearnet networking. Its extension blocks all `.onion` and `.i2p` requests from that
+profile. For a top-level navigation, it asks a token-gated loopback helper to apply the
+normal route and consent policy, then opens the destination in a separate transport
+profile and browser process.
+
 ## Main Components
 
 - `ampbrowser.routing`: deterministic URL-to-transport rules.
 - `ampbrowser.adapters`: transport ownership, setup, inspection, and health contracts.
 - `ampbrowser.transports`: local readiness checks for Tor, I2P, IPFS, Reticulum, and Gemini.
 - `ampbrowser.plan`: dry-run action planner for browser launches.
+- `ampbrowser.broker`: validated handoff from the clearnet entry profile to an isolated
+  transport profile.
 - `ampbrowser.launch`: side-effect-free launch specs and first-use consent state.
 - `ampbrowser.platforms`: platform capability matrix for desktop, Android, and iOS.
 - `ampbrowser.candidates`: evaluated transport candidates before active adapter support.
@@ -49,8 +57,21 @@ Generated backend metadata lives in
 
 The first implementation path is documented in [desktop vertical](desktop-vertical.md).
 
+## Isolation Boundaries
+
+- Browser storage is isolated by transport profile.
+- Transport runtime state is isolated under AMPB-owned transport directories when AMPB
+  manages the daemon.
+- A transport profile remains sticky: ordinary navigation stays in that profile and uses
+  its configured proxy until the user explicitly starts a different context.
+- The loopback helper accepts a random per-launch token and recomputes the URL route before
+  opening it. A caller cannot label an I2P URL as Tor or vice versa.
+
+These controls prevent accidental browser-state mixing. They do not by themselves provide
+Tor Browser fingerprinting resistance or make non-anonymous transports anonymous.
+
 ## Relationship To AMPG
 
-AMPG publishes protocol-specific site variants. AMPB opens those variants with the right
-transport and profile. Wownero is the shared fixture for static publishing, while
-interactive targets exercise sessions, dynamic assets, forms, and script policy.
+AMPG publishes protocol-specific site variants and declares their expected transport,
+profile, and isolation mode in fixture manifests. AMPB validates and enforces the browser
+side of that contract. AMPG never controls local browser daemon ownership or profile state.

docs/broker.md

@@ -0,0 +1,44 @@
+# Transport Broker
+
+> Status: draft | Updated 2026-07-11 | Applies to: AMPB desktop users and implementers
+
+The transport broker is AMPB's clearnet entry profile. It gives users one place to begin
+without combining clearnet, Tor, and I2P browser storage or proxy policy.
+
+## Handoff
+
+1. The broker profile begins a top-level navigation.
+2. Its extension recognizes `.onion` or `.i2p` and cancels the request.
+3. A token-gated loopback helper independently routes the URL.
+4. If needed, AMPB asks for first-use consent and starts or adopts the transport.
+5. AMPB opens the URL in `.ampb/profiles/tor` or `.ampb/profiles/i2p` with that profile's
+   proxy policy.
+6. The broker tab reports that the route opened in an isolated context.
+
+AMPB records the process it launches for each exact profile. Later handoffs reuse only a
+live process recorded for that profile; otherwise AMPB launches a new isolated process.
+
+The helper rejects a handoff when the supplied transport does not match the URL. It is
+tied to the broker browser process and stops when that process exits.
+
+Subresources, frames, and background requests to alternate-network hosts are blocked in
+the clearnet broker and are not converted into handoffs. Only top-level navigation can
+open another transport context.
+
+## Boundaries
+
+The broker separates cookies, cache, history, service workers, and other profile storage
+by transport. AMPB-managed daemon state is separately stored under
+`.ampb/transports/<transport>`.
+
+Transport isolation is not an anonymity claim. Tor browsing still requires Tor Browser
+hardening and update parity before AMPB can claim equivalent fingerprinting resistance.
+I2P and Reticulum have different threat models and must be described on their own terms.
+
+## Command
+
+```sh
+python3 -m ampbrowser open https://ampgateway.site/ --broker --launch
+```
+
+`--route-aware` is retained as a compatibility alias for `--broker`.

docs/desktop-vertical.md

@@ -27,9 +27,10 @@ artifacts are available for the selected checkout.
 ## Transport Path
 
 The first transport target is Tor through an AMPB-owned Arti/Tor runtime. The current
-desktop vertical can launch a bundled Gecko runtime, start a route-aware helper, and keep
-the helper tied to the browser process. I2P uses the same route, consent, state, and
-health-check model. Reticulum follows after the resilient-network adapter is concrete.
+desktop vertical can launch a bundled Gecko runtime, start the isolated transport broker,
+and keep its token-gated helper tied to the broker process. Tor and I2P destinations launch
+in their own browser profiles after route validation and consent. Reticulum follows after
+the resilient-network adapter and renderer handoff are concrete.
 
 ## Desktop Shell
 
@@ -41,4 +42,5 @@ approval. Use `--yes` for scripted verification without showing the dialog.
 ```sh
 python3 -m ampbrowser shell http://example.onion/
 python3 -m ampbrowser shell http://example.onion/ --yes
+python3 -m ampbrowser shell https://ampgateway.site/ --broker
 ```

docs/fixture-manifests.md

@@ -1,10 +1,11 @@
 # Fixture Manifests
 
-> Status: draft | Updated 2026-07-06 | Applies to: AMPB and AMPG compatibility checks
+> Status: draft | Updated 2026-07-11 | Applies to: AMPB and AMPG compatibility checks
 
 AMPB can check AMPG fixture manifests without contacting any network. The check confirms
-that each generated fixture URL routes to the expected AMPB transport and profile, and
-that its declared interaction policy fits that transport.
+that each generated fixture URL routes to the expected AMPB transport and profile, uses
+the declared transport-profile isolation contract, and fits that transport's interaction
+policy.
 
 Route-expanded fixtures may include `route.match` and `route.fixture_path`, which identify
 the route group that produced the fixture.
@@ -20,8 +21,9 @@ manifest.
 
 ## Scope
 
-Fixture checks validate route selection and declared interaction policy only. They do not
-verify daemon health, hidden service reachability, IPFS pinning, TLS, or content freshness.
+Fixture checks validate route selection, profile isolation expectations, and declared
+interaction policy only. They do not verify process separation, daemon health, hidden
+service reachability, IPFS pinning, TLS, or content freshness.
 
 The manifest must not contain private deployment notes, service keys, credentials, or
 host inventory.

docs/open-flow.md

@@ -34,13 +34,12 @@ adopted daemon from an AMPB-owned managed process.
 through a desktop dialog when possible, falls back to a terminal prompt when needed, and
 launches through the same transport runner after approval.
 
-`ampbrowser open <url> --route-aware --launch` creates a desktop convenience profile for
-clearnet, Tor, and I2P QA. The profile uses a PAC file for `.onion` and `.i2p` routing,
-installs the AMPB route-helper extension, and starts a token-gated loopback helper tied
-to the browser process. If a user clicks an alternate-network link before its local
-transport is ready, the extension shows a setup page and asks the helper to start the
-AMPB-managed transport after approval. This mode proves routing and first-use setup; it
-is not the final per-transport storage isolation model.
+`ampbrowser open <clearnet-url> --broker --launch` creates the desktop entry profile. The
+broker has direct clearnet networking and no mixed-transport PAC. Its extension cancels
+all `.onion` and `.i2p` requests before they leave the profile. For a top-level navigation,
+it asks a token-gated loopback helper to open the URL in the isolated Tor or I2P profile.
+Missing transports use the same first-use consent flow before the handoff. `--route-aware`
+remains a compatibility alias for `--broker`.
 
 ## Examples
 
@@ -51,7 +50,7 @@ python3 -m ampbrowser open http://example.b32.i2p/ --yes
 python3 -m ampbrowser open http://example.b32.i2p/ --config examples/config.toml
 python3 -m ampbrowser open http://example.b32.i2p/ --platform android
 python3 -m ampbrowser open https://wownero.org/ --launch
-python3 -m ampbrowser open https://ampgateway.site/ --route-aware --launch
+python3 -m ampbrowser open https://ampgateway.site/ --broker --launch
 python3 -m ampbrowser open http://example.onion/ --launch
 python3 -m ampbrowser open http://example.onion/ --yes --launch
 python3 -m ampbrowser shell http://example.onion/

tests/test_broker.py

@@ -0,0 +1,54 @@
+from __future__ import annotations
+
+from pathlib import Path
+import tempfile
+import unittest
+from unittest.mock import patch
+
+from ampbrowser.broker import BrokerRouteError, open_brokered_url
+from ampbrowser.config import AppConfig
+from ampbrowser.transports import TransportStatus
+
+
+class BrokerTest(unittest.TestCase):
+    def test_broker_launches_matching_route_without_shared_profile(self) -> None:
+        status = TransportStatus(
+            transport="tor",
+            installed=True,
+            running=True,
+            endpoint="socks5://127.0.0.1:9050",
+            adoptable=True,
+            manage_supported=True,
+            note="Tor SOCKS proxy",
+        )
+
+        with tempfile.TemporaryDirectory() as tmp:
+            with patch("ampbrowser.plan.inspect_transport", return_value=status):
+                with patch("ampbrowser.broker.launch_open_plan", side_effect=lambda plan, **_: plan) as launch:
+                    result = open_brokered_url(
+                        "http://example.onion/",
+                        expected_transport="tor",
+                        consent=False,
+                        config=AppConfig(transport_modes={}),
+                        root=Path(tmp),
+                    )
+
+        self.assertEqual("ready", result.status)
+        self.assertEqual(".ampb/profiles/tor", result.profile_path)
+        self.assertFalse(result.launch_spec.broker)
+        launch.assert_called_once()
+
+    def test_broker_rejects_claimed_transport_mismatch(self) -> None:
+        with tempfile.TemporaryDirectory() as tmp:
+            with self.assertRaises(BrokerRouteError):
+                open_brokered_url(
+                    "http://example.b32.i2p/",
+                    expected_transport="tor",
+                    consent=False,
+                    config=AppConfig(transport_modes={}),
+                    root=Path(tmp),
+                )
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_cli_open.py

@@ -63,7 +63,7 @@ class CliOpenTest(unittest.TestCase):
             provider_source="bundled-sidecar",
         )
 
-        def fake_execute(open_plan, *, root: Path):
+        def fake_execute(open_plan, *, root: Path, config: AppConfig):
             return replace(
                 open_plan,
                 status="launched",
@@ -108,15 +108,22 @@ class CliOpenTest(unittest.TestCase):
         self.assertIn("prompt_shown=false", output)
         self.assertIn("prompt_approved=false", output)
 
-    def test_route_aware_open_prints_profile_and_pac_path(self) -> None:
+    def test_broker_open_prints_isolated_broker_profile(self) -> None:
+        with patch.object(sys, "stdout", new_callable=io.StringIO) as stdout:
+            code = main(["open", "https://ampgateway.site/", "--broker"])
+
+        self.assertEqual(0, code)
+        output = stdout.getvalue()
+        self.assertIn("broker=true", output)
+        self.assertIn("profile_path=.ampb/profiles/broker", output)
+        self.assertNotIn("pac_path=", output)
+
+    def test_route_aware_flag_remains_broker_alias(self) -> None:
         with patch.object(sys, "stdout", new_callable=io.StringIO) as stdout:
             code = main(["open", "https://ampgateway.site/", "--route-aware"])
 
         self.assertEqual(0, code)
-        output = stdout.getvalue()
-        self.assertIn("route_aware=true", output)
-        self.assertIn("profile_path=.ampb/profiles/route-aware", output)
-        self.assertIn("pac_path=.ampb/profiles/route-aware/ampb-proxy.pac", output)
+        self.assertIn("broker=true", stdout.getvalue())
 
     def test_hidden_helper_command_passes_watch_pid(self) -> None:
         with patch("ampbrowser.cli.serve_route_helper") as helper:

tests/test_config.py

@@ -40,6 +40,7 @@ enabled = false
 
             config = load_config(Path(tmp), path)
 
+        self.assertEqual(str(path.resolve()), config.config_path)
         self.assertEqual(".local/ampb", config.state_dir)
         self.assertEqual("/opt/ampb/firefox", config.runtime_path)
         self.assertEqual("adopt", config.transport_mode("tor"))

tests/test_fixtures.py

@@ -26,7 +26,11 @@ class FixtureCheckTest(unittest.TestCase):
                             {
                                 "protocol": "tor",
                                 "url": "http://wownero.onion/",
-                                "checks": {"transport": "tor", "profile": "tor"},
+                                "checks": {
+                                    "transport": "tor",
+                                    "profile": "tor",
+                                    "isolation": "transport-profile",
+                                },
                             },
                             {
                                 "protocol": "ipfs",
@@ -45,6 +49,7 @@ class FixtureCheckTest(unittest.TestCase):
 
         self.assertTrue(result.ok)
         self.assertEqual(3, len(result.checks))
+        self.assertEqual("transport-profile", result.checks[1].actual_isolation)
         self.assertEqual("/snapshot/*", result.checks[2].route_match)
         self.assertEqual("/snapshot/", result.checks[2].fixture_path)
 

tests/test_launch.py

@@ -6,11 +6,22 @@ import tempfile
 from pathlib import Path
 
 from ampbrowser.config import AppConfig
-from ampbrowser.launch import RouteHelperLaunch, execute_open, prepare_open
+from ampbrowser.launch import RouteHelperLaunch, _route_helper_command, execute_open, prepare_open
 from ampbrowser.transports import TransportStatus
 
 
 class PrepareOpenTest(unittest.TestCase):
+    def test_route_helper_command_preserves_selected_config(self) -> None:
+        command = _route_helper_command(
+            root=Path("/tmp/ampb-root"),
+            port=44001,
+            token="test-token",
+            watch_pid=9876,
+            config_path=Path("/tmp/ampb-config.toml"),
+        )
+
+        self.assertEqual(("--config", "/tmp/ampb-config.toml"), command[-2:])
+
     def test_clearnet_is_ready_without_consent(self) -> None:
         config = AppConfig(runtime_path="/opt/ampb/firefox", transport_modes={})
 
@@ -130,25 +141,25 @@ class PrepareOpenTest(unittest.TestCase):
             self.assertTrue(user_js.exists())
             self.assertIn('user_pref("network.proxy.type", 0);', user_js.read_text(encoding="utf-8"))
 
-    def test_route_aware_open_writes_pac_profile(self) -> None:
+    def test_broker_open_writes_direct_profile_and_handoff_extension(self) -> None:
         with tempfile.TemporaryDirectory() as tmp:
             root = Path(tmp)
             runtime = root / "firefox"
             runtime.write_text("#!/bin/sh\n", encoding="utf-8")
             config = AppConfig(runtime_path=str(runtime), transport_modes={})
-            plan = prepare_open("https://ampgateway.site/", config=config, route_aware=True)
+            plan = prepare_open("https://ampgateway.site/", config=config, broker=True)
 
-            self.assertEqual(".ampb/profiles/route-aware", plan.profile_path)
+            self.assertEqual(".ampb/profiles/broker", plan.profile_path)
             self.assertIsNotNone(plan.launch_spec)
-            self.assertTrue(plan.launch_spec.route_aware)
-            self.assertEqual(".ampb/profiles/route-aware/ampb-proxy.pac", plan.launch_spec.pac_path)
-            self.assertIn('user_pref("network.proxy.type", 2);', plan.launch_spec.prefs)
-            self.assertIn("__AMPB_ROUTE_AWARE_PAC_URL__", "\n".join(plan.launch_spec.prefs))
+            self.assertTrue(plan.launch_spec.broker)
+            self.assertIn('user_pref("network.proxy.type", 0);', plan.launch_spec.prefs)
 
+            planned_helper = RouteHelperLaunch("planned", endpoint="http://127.0.0.1:44001/", token="test-token")
             helper = RouteHelperLaunch("started", endpoint="http://127.0.0.1:44001/", token="test-token", pid=4321)
-            with patch("ampbrowser.launch._start_route_helper", return_value=helper):
-                with patch("ampbrowser.launch.subprocess.Popen") as popen:
-                    launched = execute_open(plan, root=root)
+            with patch("ampbrowser.launch._route_helper_launch_plan", return_value=planned_helper):
+                with patch("ampbrowser.launch._start_route_helper", return_value=helper):
+                    with patch("ampbrowser.launch.subprocess.Popen") as popen:
+                        launched = execute_open(plan, root=root)
 
             self.assertEqual("launched", launched.status)
             self.assertEqual("started", launched.route_helper_status)
@@ -159,33 +170,39 @@ class PrepareOpenTest(unittest.TestCase):
                     str(runtime),
                     "--new-instance",
                     "--profile",
-                    str(root / ".ampb/profiles/route-aware"),
+                    str(root / ".ampb/profiles/broker"),
                     "https://ampgateway.site/",
                 ),
                 cwd=str(root),
                 start_new_session=True,
             )
-            profile = root / ".ampb/profiles/route-aware"
+            profile = root / ".ampb/profiles/broker"
             user_js = (profile / "user.js").read_text(encoding="utf-8")
-            pac = (profile / "ampb-proxy.pac").read_text(encoding="utf-8")
-            self.assertIn((profile / "ampb-proxy.pac").resolve().as_uri(), user_js)
-            self.assertNotIn("__AMPB_ROUTE_AWARE_PAC_URL__", user_js)
-            self.assertIn('hasSuffix(h, ".onion")', pac)
-            self.assertIn('return "SOCKS5 127.0.0.1:9050";', pac)
-            self.assertIn('hasSuffix(h, ".i2p")', pac)
-            self.assertIn('return "PROXY 127.0.0.1:4444";', pac)
-            self.assertIn('return "DIRECT";', pac)
+            self.assertIn('user_pref("network.proxy.type", 0);', user_js)
+            self.assertFalse((profile / "ampb-proxy.pac").exists())
             extension = profile / "extensions/ampb-route-helper@such.software"
             manifest = (extension / "manifest.json").read_text(encoding="utf-8")
             background = (extension / "background.js").read_text(encoding="utf-8")
             setup = (extension / "setup.html").read_text(encoding="utf-8")
-            self.assertIn("webNavigation", manifest)
+            self.assertIn("webRequestBlocking", manifest)
+            self.assertIn("http://*.onion/*", manifest)
+            self.assertIn("wss://*.i2p/*", manifest)
+            self.assertIn("cancel: true", background)
+            self.assertIn("helper('open'", background)
             self.assertIn("install_command", background)
             self.assertIn("http://127.0.0.1:", background)
             self.assertNotIn("__AMPB_ROUTE_HELPER_URL__", background)
             self.assertNotIn("__AMPB_ROUTE_HELPER_TOKEN__", background)
             self.assertIn("Set Up Transport", setup)
             self.assertIn("install-command", setup)
+            self.assertTrue((extension / "handoff.html").exists())
+
+    def test_broker_entry_rejects_alternate_transport_url(self) -> None:
+        plan = prepare_open("http://example.onion/", broker=True)
+
+        self.assertEqual("blocked", plan.status)
+        self.assertEqual(".ampb/profiles/broker", plan.profile_path)
+        self.assertIn("broker entry URLs must use clearnet", plan.message)
 
     def test_execute_open_blocks_when_runtime_is_missing(self) -> None:
         config = AppConfig(runtime_path="/missing/ampb/firefox", transport_modes={})
@@ -196,21 +213,50 @@ class PrepareOpenTest(unittest.TestCase):
         self.assertEqual("runtime-missing", launched.status)
         self.assertIn("browser runtime not found", launched.message)
 
-    def test_route_aware_launch_stops_helper_when_browser_exits_immediately(self) -> None:
+    def test_execute_open_reuses_recorded_profile_process(self) -> None:
         with tempfile.TemporaryDirectory() as tmp:
             root = Path(tmp)
             runtime = root / "firefox"
             runtime.write_text("#!/bin/sh\n", encoding="utf-8")
             config = AppConfig(runtime_path=str(runtime), transport_modes={})
-            plan = prepare_open("https://ampgateway.site/", config=config, route_aware=True)
+            plan = prepare_open("https://example.com/", config=config)
+
+            with patch("ampbrowser.launch._active_profile_session", return_value=4321):
+                with patch("ampbrowser.launch.subprocess.Popen") as popen:
+                    popen.return_value.poll.return_value = 0
+                    opened = execute_open(plan, root=root)
+
+        self.assertEqual("opened-existing", opened.status)
+        self.assertEqual(4321, opened.browser_pid)
+        popen.assert_called_once_with(
+            (
+                str(runtime),
+                "--profile",
+                str(root / ".ampb/profiles/clearnet"),
+                "--new-tab",
+                "https://example.com/",
+            ),
+            cwd=str(root),
+            start_new_session=True,
+        )
+
+    def test_broker_launch_stops_helper_when_browser_exits_immediately(self) -> None:
+        with tempfile.TemporaryDirectory() as tmp:
+            root = Path(tmp)
+            runtime = root / "firefox"
+            runtime.write_text("#!/bin/sh\n", encoding="utf-8")
+            config = AppConfig(runtime_path=str(runtime), transport_modes={})
+            plan = prepare_open("https://ampgateway.site/", config=config, broker=True)
+            planned_helper = RouteHelperLaunch("planned", endpoint="http://127.0.0.1:44001/", token="test-token")
             helper = RouteHelperLaunch("started", endpoint="http://127.0.0.1:44001/", token="test-token", pid=4321)
 
-            with patch("ampbrowser.launch._start_route_helper", return_value=helper):
-                with patch("ampbrowser.launch._stop_route_helper", return_value="stopped") as stop_helper:
-                    with patch("ampbrowser.launch.subprocess.Popen") as popen:
-                        popen.return_value.pid = 9876
-                        popen.return_value.poll.return_value = 1
-                        launched = execute_open(plan, root=root)
+            with patch("ampbrowser.launch._route_helper_launch_plan", return_value=planned_helper):
+                with patch("ampbrowser.launch._start_route_helper", return_value=helper):
+                    with patch("ampbrowser.launch._stop_route_helper", return_value="stopped") as stop_helper:
+                        with patch("ampbrowser.launch.subprocess.Popen") as popen:
+                            popen.return_value.pid = 9876
+                            popen.return_value.poll.return_value = 1
+                            launched = execute_open(plan, root=root)
 
         self.assertEqual("browser-exited", launched.status)
         self.assertEqual(9876, launched.browser_pid)
@@ -218,20 +264,22 @@ class PrepareOpenTest(unittest.TestCase):
         self.assertIn("browser exited immediately", launched.message)
         stop_helper.assert_called_once_with(helper)
 
-    def test_route_aware_launch_starts_helper_with_browser_pid(self) -> None:
+    def test_broker_launch_starts_helper_with_browser_pid(self) -> None:
         with tempfile.TemporaryDirectory() as tmp:
             root = Path(tmp)
             runtime = root / "firefox"
             runtime.write_text("#!/bin/sh\n", encoding="utf-8")
             config = AppConfig(runtime_path=str(runtime), transport_modes={})
-            plan = prepare_open("https://ampgateway.site/", config=config, route_aware=True)
+            plan = prepare_open("https://ampgateway.site/", config=config, broker=True)
+            planned_helper = RouteHelperLaunch("planned", endpoint="http://127.0.0.1:44001/", token="test-token")
             helper = RouteHelperLaunch("started", endpoint="http://127.0.0.1:44001/", token="test-token", pid=4321)
 
-            with patch("ampbrowser.launch._start_route_helper", return_value=helper) as start_helper:
-                with patch("ampbrowser.launch.subprocess.Popen") as popen:
-                    popen.return_value.pid = 9876
-                    popen.return_value.poll.return_value = None
-                    launched = execute_open(plan, root=root)
+            with patch("ampbrowser.launch._route_helper_launch_plan", return_value=planned_helper):
+                with patch("ampbrowser.launch._start_route_helper", return_value=helper) as start_helper:
+                    with patch("ampbrowser.launch.subprocess.Popen") as popen:
+                        popen.return_value.pid = 9876
+                        popen.return_value.poll.return_value = None
+                        launched = execute_open(plan, root=root)
 
         self.assertEqual("launched", launched.status)
         start_helper.assert_called_once()

tests/test_route_helper.py

@@ -1,13 +1,16 @@
 from __future__ import annotations
 
+from dataclasses import replace
 from pathlib import Path
 import tempfile
 import unittest
 from unittest.mock import patch
 
 from ampbrowser.config import AppConfig
+from ampbrowser.launch import prepare_open
 from ampbrowser.route_helper import handle_helper_message
 from ampbrowser.transport_manager import ManagedTransportResult
+from ampbrowser.transports import TransportStatus
 
 
 class RouteHelperTest(unittest.TestCase):
@@ -81,6 +84,55 @@ class RouteHelperTest(unittest.TestCase):
         self.assertFalse(response["ok"])
         self.assertEqual("unsupported-transport", response["status"])
 
+    def test_open_hands_route_to_isolated_transport_profile(self) -> None:
+        status = TransportStatus(
+            transport="tor",
+            installed=True,
+            running=True,
+            endpoint="socks5://127.0.0.1:9050",
+            adoptable=True,
+            manage_supported=True,
+            note="Tor SOCKS proxy",
+        )
+        with patch("ampbrowser.plan.inspect_transport", return_value=status):
+            plan = prepare_open("http://example.onion/")
+        launched = replace(plan, status="launched", dry_run=False, browser_pid=4321)
+
+        with tempfile.TemporaryDirectory() as tmp:
+            with patch("ampbrowser.route_helper.open_brokered_url", return_value=launched) as broker_open:
+                response = handle_helper_message(
+                    {
+                        "action": "open",
+                        "transport": "tor",
+                        "url": "http://example.onion/",
+                        "consent": True,
+                    },
+                    root=Path(tmp),
+                    config=AppConfig(transport_modes={}),
+                )
+
+        self.assertTrue(response["ok"])
+        self.assertTrue(response["launched"])
+        self.assertEqual("tor", response["profile"])
+        self.assertEqual(".ampb/profiles/tor", response["profile_path"])
+        self.assertEqual(4321, response["browser_pid"])
+        broker_open.assert_called_once()
+
+    def test_open_rejects_transport_url_mismatch(self) -> None:
+        with tempfile.TemporaryDirectory() as tmp:
+            response = handle_helper_message(
+                {
+                    "action": "open",
+                    "transport": "tor",
+                    "url": "http://example.b32.i2p/",
+                },
+                root=Path(tmp),
+                config=AppConfig(transport_modes={}),
+            )
+
+        self.assertFalse(response["ok"])
+        self.assertEqual("route-mismatch", response["status"])
+
 
 if __name__ == "__main__":
     unittest.main()