Fixed #140 -- Added route inject config validation before route registration.

docs/en/dev/changelog.md

@@ -22,6 +22,14 @@ cut.
   action handling into focused internal modules. Command syntax and behavior are
   unchanged. ([#167](https://github.com/DevilsAutumn/quater/issues/167))
 
+- `Quater.add_route()` now validates the `inject` mapping at registration time,
+  matching `RouteGroup` behavior. Invalid injected parameter names (e.g.
+  `bad-name`) raise `ConfigurationError` and non-`Resource` values raise
+  `TypeError` when the route is added, instead of surfacing later during route
+  compilation. Deeper handler-plan checks (unused injected values, path/param
+  marker conflicts) remain compile-time.
+  ([#140](https://github.com/DevilsAutumn/quater/issues/140))
+
 ### Fixed
 
 - Fixed resource provider planning so valid provider parameters still resolve

docs/en/dev/resources.md

@@ -278,6 +278,12 @@ decorator says where its value comes from. This is the only form that a
 [`RouteGroup`](#groups) can share across several routes, so prefer it when a
 whole feature needs the same resource.
 
+The `inject` map is validated when the route is registered (via
+`app.add_route()`, `@app.get(...)`, `RouteGroup(...)`, or `group.add_route()`).
+Keys must be valid Python identifiers and values must be `Resource` instances,
+otherwise registration raises `ConfigurationError` or `TypeError` immediately
+instead of failing later during route compilation.
+
 ### In the type annotation (`Annotated[T, resource]`)
 
 Put the `Resource` in the parameter's annotation. The parameter type is still
@@ -413,6 +419,14 @@ The generated MCP and CLI schemas include `order_id`, not `session`.
 `Resource provider 'db_session' yielded more than once`
 : Use one `yield`, then cleanup after it.
 
+`Invalid injected parameter name: 'bad-name'`
+: An `inject={...}` key is not a valid Python identifier. Rename the key.
+  Raised at route registration.
+
+`inject values must be Resource instances`
+: An `inject={...}` value is not a `Resource`. Wrap the provider with
+  `Resource(...)`. Raised at route registration.
+
 `Duplicate injected parameter: session`
 : A group and a route both define `session` with different `Resource` objects.
   Use the same object or rename one parameter.

src/quater/_route_definition.py

@@ -71,7 +71,7 @@ def build_route_definition(
             cli=cli,
             route_name=route_name,
         ),
-        inject=dict(inject or {}),
+        inject=normalize_inject(inject),
         metadata=dict(metadata or {}),
         middleware=MiddlewareStack.from_parts(
             before=before,

src/quater/groups.py

@@ -138,7 +138,7 @@ def add_route(
             cli=cli,
             needs_approval=needs_approval,
             public=public,
-            inject=normalize_inject(inject),
+            inject=inject,
             metadata=metadata,
             before=before,
             after=after,

tests/unit/test_app_config.py

@@ -6,7 +6,7 @@
 
 import pytest
 
-from quater import AuthConfig, Quater, Request
+from quater import AuthConfig, Quater, Request, Resource
 from quater.config import AppConfig
 from quater.exceptions import ConfigurationError, RouteConflictError
 from quater.response import Response
@@ -486,3 +486,34 @@ async def handler() -> dict[str, bool]:
     assert route.cli is False
     assert route.needs_approval is False
     assert route.public == ()
+
+
+def test_app_add_route_rejects_invalid_inject_parameter_names() -> None:
+    async def provider() -> str:
+        return "bad"
+
+    async def handler(value: str) -> dict[str, str]:
+        return {"value": value}
+
+    app = Quater()
+    with pytest.raises(ConfigurationError, match="Invalid injected parameter name"):
+        app.add_route(
+            "GET",
+            "/",
+            handler,
+            inject={"bad-name": Resource(provider)},
+        )
+
+
+def test_app_add_route_rejects_non_resource_inject_values() -> None:
+    async def handler(value: str) -> dict[str, str]:
+        return {"value": value}
+
+    app = Quater()
+    with pytest.raises(TypeError, match="inject values must be Resource instances"):
+        app.add_route(
+            "GET",
+            "/ok",
+            handler,
+            inject=cast(dict[str, Resource[str]], {"value": object()}),
+        )