diff --git a/scripts/build_runtime_package.py b/scripts/build_runtime_package.py
index 54d1647a..1a5f02ec 100755
--- a/scripts/build_runtime_package.py
+++ b/scripts/build_runtime_package.py
@@ -58,6 +58,7 @@ TOP_LEVEL_MODULES = {
     "adapter_base",
     "agent",
     "agents_md",
+    "boot_routes",
     "card_helpers",
     "config",
     "configs_dir",
diff --git a/workspace/boot_routes.py b/workspace/boot_routes.py
new file mode 100644
index 00000000..a2c849d6
--- /dev/null
+++ b/workspace/boot_routes.py
@@ -0,0 +1,84 @@
+"""Build the Starlette routes for a workspace from its (card, adapter
+state) pair.
+
+Pairs with PR #2756, which decoupled ``/.well-known/agent-card.json`` from
+``adapter.setup()`` failure. main.py was the only consumer and was
+``# pragma: no cover`` — so the wiring (card-route mounted unconditionally,
+JSON-RPC route swapped between DefaultRequestHandler and the
+not-configured handler based on ``adapter_ready``) had no pytest coverage.
+
+A future refactor that re-couples the two would silently bypass PR #2756
+and shipped the original "stuck booting forever" UX again. That gap is
+what closes here: extract the route-assembly into a pure function whose
+behaviour is unit-testable with Starlette's TestClient, and have main.py
+call it. Issue molecule-core#2761.
+"""
+from __future__ import annotations
+
+from typing import Any
+
+from starlette.routing import Route
+
+from not_configured_handler import make_not_configured_handler
+
+# Heavy a2a-sdk imports are lazy: deferred to inside build_routes so
+# tests that exercise only the not-configured branch (no executor) don't
+# need a2a.server.request_handlers / routes stubbed in their conftest.
+# Production boot pays the import cost once, on workspace startup.
+
+
+def build_routes(
+    agent_card: Any,
+    executor: Any | None,
+    adapter_error: str | None,
+) -> list:
+    """Return the list of Starlette routes for this workspace.
+
+    Always mounts ``/.well-known/agent-card.json`` from ``agent_card``.
+
+    JSON-RPC route at ``/`` swaps based on adapter state:
+
+    * ``executor`` is non-None → ``DefaultRequestHandler`` with the
+      executor (production happy-path).
+    * ``executor`` is None → ``not_configured_handler`` returning JSON-RPC
+      ``-32603`` with ``adapter_error`` in ``error.data``. The
+      workspace stays REACHABLE (operator can introspect, deprovision,
+      redeploy with corrected env) instead of crash-looping invisibly.
+
+    The two branches are mutually exclusive — caller passes one or the
+    other, never both. Test coverage at ``tests/test_boot_routes.py``
+    pins the contract.
+    """
+    from a2a.server.routes import create_agent_card_routes
+
+    routes: list = []
+    routes.extend(create_agent_card_routes(agent_card))
+
+    if executor is not None:
+        from a2a.server.request_handlers import DefaultRequestHandler
+        from a2a.server.routes import create_jsonrpc_routes
+        from a2a.server.tasks import InMemoryTaskStore
+
+        handler = DefaultRequestHandler(
+            agent_executor=executor,
+            task_store=InMemoryTaskStore(),
+            agent_card=agent_card,
+        )
+        # enable_v0_3_compat=True is the JSON-RPC wire-compat path: clients
+        # using v0.3-shaped payloads (`"role": "user"` lowercase + camelCase
+        # Pydantic field names) can talk to us without re-deploying.
+        # Outbound payloads must also use v0.3 shape — see main.py's
+        # original comment block for the full a2a-sdk 1.x migration note.
+        routes.extend(
+            create_jsonrpc_routes(
+                request_handler=handler,
+                rpc_url="/",
+                enable_v0_3_compat=True,
+            )
+        )
+    else:
+        routes.append(
+            Route("/", make_not_configured_handler(adapter_error), methods=["POST"])
+        )
+
+    return routes
diff --git a/workspace/main.py b/workspace/main.py
index ca81ea01..5ae5ebef 100644
--- a/workspace/main.py
+++ b/workspace/main.py
@@ -277,54 +277,16 @@ async def main():  # pragma: no cover
 
     # 7. Wrap in A2A.
     #
-    # Regression fix (#204): PR #198 tried to wire push_config_store +
-    # push_sender to satisfy #175 (push notification capability), but
-    # PushNotificationSender is an abstract base class in the a2a-sdk and
-    # can't be instantiated directly. Passing it crashed main.py on startup
-    # with `TypeError: Can't instantiate abstract class`. Dropped back to
-    # DefaultRequestHandler's own defaults — pushNotifications capability
-    # in the AgentCard below is still advertised via AgentCapabilities so
-    # clients know we COULD do pushes; actually implementing them requires
-    # a concrete sender subclass, tracked as a Phase-H follow-up to #175.
-    routes = []
-    routes.extend(create_agent_card_routes(agent_card))
-
-    if adapter_ready:
-        handler = DefaultRequestHandler(
-            agent_executor=executor,
-            task_store=InMemoryTaskStore(),
-            # a2a-sdk 1.x added agent_card as a required positional/keyword
-            # argument — it's used internally for capability dispatch (e.g.
-            # routing tasks/get historyLength based on the card's protocol
-            # version). Pass the same agent_card we registered with the
-            # platform so the handler's capability surface matches what the
-            # AgentCard advertises.
-            agent_card=agent_card,
-        )
-        # v1: replace A2AStarletteApplication with Starlette route factory.
-        # rpc_url is required in a2a-sdk 1.x (was implicit at root in 0.x).
-        # Use '/' to match a2a.utils.constants.DEFAULT_RPC_URL — that's also
-        # what the platform's a2a_proxy.go POSTs to (it forwards to the
-        # workspace's URL without appending a path). Card endpoint stays at
-        # the well-known path /.well-known/agent-card.json (handled by
-        # create_agent_card_routes default).
-        # enable_v0_3_compat=True is the JSON-RPC wire-compat path: clients
-        # using v0.3-shaped payloads (`"role": "user"` lowercase + camelCase
-        # Pydantic field names) can talk to us without re-deploying.
-        routes.extend(create_jsonrpc_routes(request_handler=handler, rpc_url="/", enable_v0_3_compat=True))
-    else:
-        # Misconfigured: serve the card but reject JSON-RPC with -32603 so
-        # canvas surfaces a useful "agent not configured: <reason>" instead
-        # of letting requests time out. Handler factory is in its own module
-        # so the behavior is unit-testable (workspace/tests/test_not_configured_handler.py).
-        from starlette.routing import Route
-        from not_configured_handler import make_not_configured_handler
-
-        routes.append(
-            Route("/", make_not_configured_handler(adapter_error), methods=["POST"])
-        )
-
-    app = Starlette(routes=routes)
+    # Route assembly is in workspace/boot_routes.py so the contract —
+    # card always mounted, JSON-RPC route swaps based on adapter state
+    # (DefaultRequestHandler when executor is non-None, not_configured
+    # handler returning -32603 otherwise) — is unit-testable with
+    # Starlette's TestClient. main.py is `# pragma: no cover` so without
+    # this extraction a future refactor that re-coupled card + setup()
+    # would silently bypass PR #2756. tests/test_boot_routes.py pins
+    # the four-branch contract.
+    from boot_routes import build_routes
+    app = Starlette(routes=build_routes(agent_card, executor, adapter_error))
 
     # 8. Register with platform
     # When adapter.setup() failed, advertise via configuration_status so
diff --git a/workspace/tests/conftest.py b/workspace/tests/conftest.py
index dfb81472..3bbb0eee 100644
--- a/workspace/tests/conftest.py
+++ b/workspace/tests/conftest.py
@@ -181,6 +181,77 @@ def _make_a2a_mocks():
     types_mod.AgentInterface = AgentInterface
     types_mod.AgentCard = AgentCard
 
+    # a2a.server.routes — used by boot_routes.build_routes (PR #2756 chain
+    # / #2761) to mount /.well-known/agent-card.json. The real SDK builds
+    # a Starlette route that serializes the card on each request; the stub
+    # mirrors that behaviour with json.dumps over the card's __dict__ so
+    # TestClient.get("/.well-known/agent-card.json") returns the same
+    # shape canvas would see in production.
+    routes_mod = ModuleType("a2a.server.routes")
+
+    def _create_agent_card_routes(card):
+        from starlette.responses import JSONResponse
+        from starlette.routing import Route
+
+        async def _card_handler(_request):
+            # Convert the stub AgentCard into a JSON-serialisable dict.
+            # Real a2a.types.AgentCard is a Pydantic model with proper
+            # serialisation; the stub stores attrs raw, so we walk
+            # __dict__ and serialise nested AgentSkill objects too.
+            def _to_dict(obj):
+                if hasattr(obj, "__dict__"):
+                    return {k: _to_dict(v) for k, v in vars(obj).items()}
+                if isinstance(obj, list):
+                    return [_to_dict(x) for x in obj]
+                if isinstance(obj, dict):
+                    return {k: _to_dict(v) for k, v in obj.items()}
+                return obj
+
+            return JSONResponse(_to_dict(card))
+
+        return [Route("/.well-known/agent-card.json", _card_handler, methods=["GET"])]
+
+    def _create_jsonrpc_routes(request_handler=None, rpc_url="/", **_kwargs):
+        from starlette.responses import JSONResponse
+        from starlette.routing import Route
+
+        async def _jsonrpc_handler(_request):
+            # Stub: real DefaultRequestHandler dispatches to the executor;
+            # tests that need real behaviour will use a test-side mock.
+            # This stub just returns a JSON-RPC envelope so the not-configured
+            # branch's discriminator (`error.data` containing "setup() failed")
+            # has something to differ from.
+            return JSONResponse({"jsonrpc": "2.0", "result": "stub-jsonrpc-handler"})
+
+        return [Route(rpc_url, _jsonrpc_handler, methods=["POST"])]
+
+    routes_mod.create_agent_card_routes = _create_agent_card_routes
+    routes_mod.create_jsonrpc_routes = _create_jsonrpc_routes
+    sys.modules["a2a.server.routes"] = routes_mod
+
+    # a2a.server.request_handlers — used by boot_routes' executor branch.
+    # DefaultRequestHandler stub takes the same kwargs as the real one;
+    # tests that exercise the executor path don't poke at the handler's
+    # internals, only that it gets mounted at "/".
+    rh_mod = ModuleType("a2a.server.request_handlers")
+
+    class DefaultRequestHandler:
+        def __init__(self, agent_executor=None, task_store=None, agent_card=None, **_kwargs):
+            self.agent_executor = agent_executor
+            self.task_store = task_store
+            self.agent_card = agent_card
+
+    rh_mod.DefaultRequestHandler = DefaultRequestHandler
+    sys.modules["a2a.server.request_handlers"] = rh_mod
+
+    # InMemoryTaskStore is exposed via a2a.server.tasks (already stubbed
+    # above with TaskUpdater). Add it as a no-op class.
+    class _InMemoryTaskStore:
+        def __init__(self):
+            pass
+
+    tasks_mod.InMemoryTaskStore = _InMemoryTaskStore
+
     # a2a.helpers (v1: moved from a2a.utils, renamed new_agent_text_message
     # → new_text_message). Mock both names — production code only calls
     # new_text_message, but if any test still references the old name it
diff --git a/workspace/tests/test_boot_routes.py b/workspace/tests/test_boot_routes.py
new file mode 100644
index 00000000..d38b4ca8
--- /dev/null
+++ b/workspace/tests/test_boot_routes.py
@@ -0,0 +1,213 @@
+"""Integration tests for boot_routes.build_routes — pin the contract that
+PR #2756's card-vs-setup decoupling depends on.
+
+Why these matter (issue #2761): main.py is ``# pragma: no cover``. The
+inline if/else that mounted ``DefaultRequestHandler`` vs the
+not-configured handler had no pytest coverage; a future refactor that
+re-coupled card and setup() would have shipped the original "stuck
+booting forever" UX again. Extracting to ``boot_routes.build_routes``
++ these tests make the contract regression-proof.
+
+Each test exercises a real Starlette TestClient against the routes —
+no uvicorn, no socket, but every assertion is the same one canvas's
+TranscriptHandler / a2a_proxy would make in production.
+"""
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+from unittest.mock import MagicMock
+
+import pytest
+
+# Make workspace/ importable in test isolation — same pattern as the
+# adjacent tests (test_not_configured_handler.py, test_card_helpers.py).
+WORKSPACE_DIR = Path(__file__).resolve().parents[1]
+if str(WORKSPACE_DIR) not in sys.path:
+    sys.path.insert(0, str(WORKSPACE_DIR))
+
+
+@pytest.fixture
+def agent_card():
+    """Build a minimal AgentCard the way main.py does at boot."""
+    from a2a.types import (
+        AgentCard,
+        AgentCapabilities,
+        AgentInterface,
+        AgentSkill,
+    )
+
+    return AgentCard(
+        name="test-agent",
+        description="test-agent",
+        version="0.0.0",
+        supported_interfaces=[
+            AgentInterface(protocol_binding="https://a2a.g/v1", url="http://test:8000")
+        ],
+        capabilities=AgentCapabilities(streaming=True, push_notifications=False),
+        skills=[
+            AgentSkill(id="echo", name="echo", description="echo", tags=[], examples=[])
+        ],
+        default_input_modes=["text/plain"],
+        default_output_modes=["text/plain"],
+    )
+
+
+# ---- card route always mounted, regardless of adapter state -------------
+
+
+def test_card_route_serves_200_when_adapter_ready(agent_card):
+    """Adapter setup OK → card serves 200, the canonical happy path."""
+    from starlette.applications import Starlette
+    from starlette.testclient import TestClient
+
+    from boot_routes import build_routes
+
+    fake_executor = MagicMock()
+    app = Starlette(routes=build_routes(agent_card, fake_executor, None))
+    client = TestClient(app)
+    resp = client.get("/.well-known/agent-card.json")
+    assert resp.status_code == 200
+    body = resp.json()
+    assert body["name"] == "test-agent"
+
+
+def test_card_route_serves_200_when_adapter_failed(agent_card):
+    """Adapter setup raised → card route is STILL mounted with the same
+    static skills. This is the entire point of PR #2756: a misconfigured
+    workspace stays REACHABLE so canvas can show the user a clear error
+    instead of silently looking dead."""
+    from starlette.applications import Starlette
+    from starlette.testclient import TestClient
+
+    from boot_routes import build_routes
+
+    app = Starlette(
+        routes=build_routes(
+            agent_card, executor=None, adapter_error="MISSING_API_KEY"
+        )
+    )
+    client = TestClient(app)
+    resp = client.get("/.well-known/agent-card.json")
+    assert resp.status_code == 200
+    body = resp.json()
+    assert body["name"] == "test-agent"
+    # Skill stubs survive even though setup() didn't run.
+    assert any(s.get("id") == "echo" for s in body.get("skills", []))
+
+
+# ---- JSON-RPC route swaps based on executor presence -------------------
+
+
+def test_jsonrpc_returns_503_when_no_executor(agent_card):
+    """The not-configured branch: POST / returns 503 with JSON-RPC -32603
+    and the adapter_error in error.data. This is what canvas sees when a
+    user tries to message a workspace whose setup() failed — turns a
+    "stuck silent" workspace into "agent not configured: <reason>"."""
+    from starlette.applications import Starlette
+    from starlette.testclient import TestClient
+
+    from boot_routes import build_routes
+
+    app = Starlette(
+        routes=build_routes(
+            agent_card,
+            executor=None,
+            adapter_error="RuntimeError: Neither OPENAI_API_KEY nor MINIMAX_API_KEY is set",
+        )
+    )
+    client = TestClient(app)
+    resp = client.post(
+        "/",
+        json={"jsonrpc": "2.0", "id": 42, "method": "message/send"},
+    )
+    assert resp.status_code == 503
+    body = resp.json()
+    assert body["jsonrpc"] == "2.0"
+    assert body["id"] == 42  # echoed
+    assert body["error"]["code"] == -32603
+    assert "MINIMAX_API_KEY" in body["error"]["data"]
+
+
+def test_jsonrpc_returns_503_with_generic_when_no_error_string(agent_card):
+    """Defensive: if main.py reached this branch without a captured
+    error string (shouldn't happen in practice but the helper is
+    defensive), the handler still returns -32603 with a generic
+    fallback so the operator gets a useful response shape."""
+    from starlette.applications import Starlette
+    from starlette.testclient import TestClient
+
+    from boot_routes import build_routes
+
+    app = Starlette(
+        routes=build_routes(agent_card, executor=None, adapter_error=None)
+    )
+    client = TestClient(app)
+    resp = client.post(
+        "/", json={"jsonrpc": "2.0", "id": 1, "method": "message/send"}
+    )
+    assert resp.status_code == 503
+    assert resp.json()["error"]["code"] == -32603
+    # Falls back to generic "adapter.setup() failed".
+    assert "setup() failed" in resp.json()["error"]["data"]
+
+
+# ---- Specific regression: re-coupling card to setup would break this ---
+
+
+def test_card_route_does_not_depend_on_executor(agent_card):
+    """Direct regression test for PR #2756. If a future refactor moved
+    create_agent_card_routes into the executor-only branch, this test
+    would catch it: the card MUST be served from a code path that runs
+    even when executor is None."""
+    from boot_routes import build_routes
+
+    routes_with_executor = build_routes(agent_card, MagicMock(), None)
+    routes_without_executor = build_routes(agent_card, None, "err")
+
+    # Both branches mount /.well-known/agent-card.json. Find by path.
+    def has_card_route(routes):
+        for r in routes:
+            for attr in ("path", "path_format"):
+                p = getattr(r, attr, None)
+                if p and "agent-card.json" in p:
+                    return True
+        return False
+
+    assert has_card_route(routes_with_executor), (
+        "card route MUST be mounted on the executor-present path"
+    )
+    assert has_card_route(routes_without_executor), (
+        "card route MUST be mounted on the executor-missing path "
+        "(this is the PR #2756 contract — re-coupling here breaks tenant readiness)"
+    )
+
+
+def test_executor_present_does_not_mount_not_configured_handler(agent_card):
+    """Sanity: when executor is present, the not-configured handler
+    must NOT be mounted at /. Otherwise a healthy workspace would
+    return -32603 to every JSON-RPC call.
+
+    We call POST / with a malformed JSON-RPC body and assert the
+    response is NOT the -32603 not-configured envelope. (The real
+    DefaultRequestHandler may return its own error for the malformed
+    payload, but it won't have ``data: "adapter.setup() failed"``.)"""
+    from starlette.applications import Starlette
+    from starlette.testclient import TestClient
+
+    from boot_routes import build_routes
+
+    fake_executor = MagicMock()
+    app = Starlette(routes=build_routes(agent_card, fake_executor, None))
+    client = TestClient(app)
+    resp = client.post(
+        "/", json={"jsonrpc": "2.0", "id": 1, "method": "message/send"}
+    )
+    body = resp.json() if resp.headers.get("content-type", "").startswith("application/json") else {}
+    # Whatever DefaultRequestHandler does, it isn't the not-configured
+    # envelope. The cheap discriminator: error.data won't say "setup() failed".
+    err = body.get("error") or {}
+    data = err.get("data") if isinstance(err, dict) else ""
+    assert "setup() failed" not in (data or ""), (
+        "executor-present branch must not mount the not-configured handler"
+    )