fixing examples and adding doc strings

mcp_docs/modules/openapi_first.app.json

@@ -29,8 +29,8 @@
         "name": "OpenAPIFirstApp",
         "kind": "class",
         "path": "openapi_first.app.OpenAPIFirstApp",
-        "signature": "<bound method Class.signature of Class('OpenAPIFirstApp', 49, 118)>",
+        "signature": "<bound method Class.signature of Class('OpenAPIFirstApp', 49, 120)>",
-        "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+        "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
         "members": {
           "openapi": {
             "name": "openapi",

mcp_docs/modules/openapi_first.client.json

@@ -2,7 +2,7 @@
   "module": "openapi_first.client",
   "content": {
     "path": "openapi_first.client",
-    "docstring": null,
+    "docstring": "openapi_first.client\n====================\n\nOpenAPI-first HTTP client for contract-driven services.\n\nThis module provides `OpenAPIClient`, a thin, strict HTTP client that\nderives all callable operations directly from an OpenAPI 3.x specification.\n\nIt is the client counterpart to `OpenAPIFirstApp`.\n\nCore principles\n---------------\n- The OpenAPI specification is the single source of truth.\n- Each operationId becomes a callable Python method.\n- No implicit schema mutation or inference.\n- No code generation step.\n- Minimal abstraction over httpx.\n\nWhat this module does\n---------------------\n- Parses an OpenAPI 3.x specification.\n- Dynamically creates one callable per operationId.\n- Enforces presence of:\n  - servers\n  - paths\n  - operationId\n- Formats path parameters safely.\n- Handles JSON request bodies explicitly.\n- Returns raw `httpx.Response` objects.\n\nWhat this module does NOT do\n----------------------------\n- It does not generate client code.\n- It does not validate request/response schemas.\n- It does not deserialize responses.\n- It does not retry requests.\n- It does not implement authentication helpers.\n- It does not assume non-2xx responses are failures.\n\nIntended usage\n--------------\nThis client is designed for:\n\n- Service-to-service communication\n- Integration testing\n- Contract-driven internal SDK usage\n- Systems that want OpenAPI-first symmetry with `OpenAPIFirstApp`\n\nDesign constraints\n------------------\n- Only the first server in the OpenAPI `servers` list is used if\n  `base_url` is not explicitly provided.\n- Only explicitly declared request bodies are allowed.\n- `application/json` is handled natively; other media types are sent as raw content.\n- All responses are returned as-is.",
     "objects": {
       "Any": {
         "name": "Any",
@@ -57,15 +57,15 @@
         "name": "OpenAPIClientError",
         "kind": "class",
         "path": "openapi_first.client.OpenAPIClientError",
-        "signature": "<bound method Class.signature of Class('OpenAPIClientError', 9, 10)>",
+        "signature": "<bound method Class.signature of Class('OpenAPIClientError', 67, 68)>",
         "docstring": "Raised when an OpenAPI client operation fails."
       },
       "OpenAPIClient": {
         "name": "OpenAPIClient",
         "kind": "class",
         "path": "openapi_first.client.OpenAPIClient",
-        "signature": "<bound method Class.signature of Class('OpenAPIClient', 13, 176)>",
+        "signature": "<bound method Class.signature of Class('OpenAPIClient', 71, 291)>",
-        "docstring": "OpenAPI-first HTTP client (httpx-based).\n\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation",
+        "docstring": "OpenAPI-first HTTP client (httpx-based).\n\nThis client derives all callable methods directly from an OpenAPI 3.x\nspecification. Each operationId becomes a method on the client\ninstance.\n\nDesign principles\n-----------------\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation\n- Returns raw httpx.Response objects\n- No response validation or deserialization\n\nParameters\n----------\nspec : dict\n    Parsed OpenAPI 3.x specification.\nbase_url : str | None\n    Base URL of the target service. If omitted, the first entry\n    in the OpenAPI `servers` list is used.\nclient : httpx.Client | None\n    Optional preconfigured httpx client instance.\n\nRaises\n------\nOpenAPIClientError\n    If:\n    - No servers are defined and base_url is not provided\n    - OpenAPI spec has no paths\n    - An operation is missing operationId\n    - Duplicate operationIds are detected\n    - Required path parameters are missing\n    - Required request body is missing\n\n Example\n-------\n```python\nfrom openapi_first import loader, client\n\nspec = loader.load_openapi(\"openapi.yaml\")\n\napi = client.OpenAPIClient(\n    spec=spec,\n    base_url=\"http://localhost:8000\",\n)\n\n# Call operationId: getUser\nresponse = api.getUser(\n    path_params={\"user_id\": 123}\n)\n\nprint(response.status_code)\nprint(response.json())\n\n# Call operationId: createUser\nresponse = api.createUser(\n    body={\"name\": \"Bob\"}\n)\n\nprint(response.status_code)\n```",
         "members": {
           "spec": {
             "name": "spec",
@@ -92,7 +92,7 @@
             "name": "operations",
             "kind": "function",
             "path": "openapi_first.client.OpenAPIClient.operations",
-            "signature": "<bound method Function.signature of Function('operations', 45, 46)>",
+            "signature": "<bound method Function.signature of Function('operations', 160, 161)>",
             "docstring": null
           }
         }

mcp_docs/modules/openapi_first.json

@@ -36,8 +36,8 @@
             "name": "OpenAPIFirstApp",
             "kind": "class",
             "path": "openapi_first.app.OpenAPIFirstApp",
-            "signature": "<bound method Class.signature of Class('OpenAPIFirstApp', 49, 118)>",
+            "signature": "<bound method Class.signature of Class('OpenAPIFirstApp', 49, 120)>",
-            "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+            "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
             "members": {
               "openapi": {
                 "name": "openapi",
@@ -178,7 +178,7 @@
         "kind": "module",
         "path": "openapi_first.client",
         "signature": null,
-        "docstring": null,
+        "docstring": "openapi_first.client\n====================\n\nOpenAPI-first HTTP client for contract-driven services.\n\nThis module provides `OpenAPIClient`, a thin, strict HTTP client that\nderives all callable operations directly from an OpenAPI 3.x specification.\n\nIt is the client counterpart to `OpenAPIFirstApp`.\n\nCore principles\n---------------\n- The OpenAPI specification is the single source of truth.\n- Each operationId becomes a callable Python method.\n- No implicit schema mutation or inference.\n- No code generation step.\n- Minimal abstraction over httpx.\n\nWhat this module does\n---------------------\n- Parses an OpenAPI 3.x specification.\n- Dynamically creates one callable per operationId.\n- Enforces presence of:\n  - servers\n  - paths\n  - operationId\n- Formats path parameters safely.\n- Handles JSON request bodies explicitly.\n- Returns raw `httpx.Response` objects.\n\nWhat this module does NOT do\n----------------------------\n- It does not generate client code.\n- It does not validate request/response schemas.\n- It does not deserialize responses.\n- It does not retry requests.\n- It does not implement authentication helpers.\n- It does not assume non-2xx responses are failures.\n\nIntended usage\n--------------\nThis client is designed for:\n\n- Service-to-service communication\n- Integration testing\n- Contract-driven internal SDK usage\n- Systems that want OpenAPI-first symmetry with `OpenAPIFirstApp`\n\nDesign constraints\n------------------\n- Only the first server in the OpenAPI `servers` list is used if\n  `base_url` is not explicitly provided.\n- Only explicitly declared request bodies are allowed.\n- `application/json` is handled natively; other media types are sent as raw content.\n- All responses are returned as-is.",
         "members": {
           "Any": {
             "name": "Any",
@@ -233,15 +233,15 @@
             "name": "OpenAPIClientError",
             "kind": "class",
             "path": "openapi_first.client.OpenAPIClientError",
-            "signature": "<bound method Class.signature of Class('OpenAPIClientError', 9, 10)>",
+            "signature": "<bound method Class.signature of Class('OpenAPIClientError', 67, 68)>",
             "docstring": "Raised when an OpenAPI client operation fails."
           },
           "OpenAPIClient": {
             "name": "OpenAPIClient",
             "kind": "class",
             "path": "openapi_first.client.OpenAPIClient",
-            "signature": "<bound method Class.signature of Class('OpenAPIClient', 13, 176)>",
+            "signature": "<bound method Class.signature of Class('OpenAPIClient', 71, 291)>",
-            "docstring": "OpenAPI-first HTTP client (httpx-based).\n\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation",
+            "docstring": "OpenAPI-first HTTP client (httpx-based).\n\nThis client derives all callable methods directly from an OpenAPI 3.x\nspecification. Each operationId becomes a method on the client\ninstance.\n\nDesign principles\n-----------------\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation\n- Returns raw httpx.Response objects\n- No response validation or deserialization\n\nParameters\n----------\nspec : dict\n    Parsed OpenAPI 3.x specification.\nbase_url : str | None\n    Base URL of the target service. If omitted, the first entry\n    in the OpenAPI `servers` list is used.\nclient : httpx.Client | None\n    Optional preconfigured httpx client instance.\n\nRaises\n------\nOpenAPIClientError\n    If:\n    - No servers are defined and base_url is not provided\n    - OpenAPI spec has no paths\n    - An operation is missing operationId\n    - Duplicate operationIds are detected\n    - Required path parameters are missing\n    - Required request body is missing\n\n Example\n-------\n```python\nfrom openapi_first import loader, client\n\nspec = loader.load_openapi(\"openapi.yaml\")\n\napi = client.OpenAPIClient(\n    spec=spec,\n    base_url=\"http://localhost:8000\",\n)\n\n# Call operationId: getUser\nresponse = api.getUser(\n    path_params={\"user_id\": 123}\n)\n\nprint(response.status_code)\nprint(response.json())\n\n# Call operationId: createUser\nresponse = api.createUser(\n    body={\"name\": \"Bob\"}\n)\n\nprint(response.status_code)\n```",
             "members": {
               "spec": {
                 "name": "spec",
@@ -268,7 +268,7 @@
                 "name": "operations",
                 "kind": "function",
                 "path": "openapi_first.client.OpenAPIClient.operations",
-                "signature": "<bound method Function.signature of Function('operations', 45, 46)>",
+                "signature": "<bound method Function.signature of Function('operations', 160, 161)>",
                 "docstring": null
               }
             }
@@ -461,7 +461,7 @@
                     "kind": "class",
                     "path": "openapi_first.templates.crud_app.main.OpenAPIFirstApp",
                     "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-                    "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+                    "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
                     "members": {
                       "openapi": {
                         "name": "openapi",
@@ -579,7 +579,7 @@
                     "kind": "class",
                     "path": "openapi_first.templates.crud_app.test_crud_app.OpenAPIClient",
                     "signature": "<bound method Alias.signature of Alias('OpenAPIClient', 'openapi_first.client.OpenAPIClient')>",
-                    "docstring": "OpenAPI-first HTTP client (httpx-based).\n\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation",
+                    "docstring": "OpenAPI-first HTTP client (httpx-based).\n\nThis client derives all callable methods directly from an OpenAPI 3.x\nspecification. Each operationId becomes a method on the client\ninstance.\n\nDesign principles\n-----------------\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation\n- Returns raw httpx.Response objects\n- No response validation or deserialization\n\nParameters\n----------\nspec : dict\n    Parsed OpenAPI 3.x specification.\nbase_url : str | None\n    Base URL of the target service. If omitted, the first entry\n    in the OpenAPI `servers` list is used.\nclient : httpx.Client | None\n    Optional preconfigured httpx client instance.\n\nRaises\n------\nOpenAPIClientError\n    If:\n    - No servers are defined and base_url is not provided\n    - OpenAPI spec has no paths\n    - An operation is missing operationId\n    - Duplicate operationIds are detected\n    - Required path parameters are missing\n    - Required request body is missing\n\n Example\n-------\n```python\nfrom openapi_first import loader, client\n\nspec = loader.load_openapi(\"openapi.yaml\")\n\napi = client.OpenAPIClient(\n    spec=spec,\n    base_url=\"http://localhost:8000\",\n)\n\n# Call operationId: getUser\nresponse = api.getUser(\n    path_params={\"user_id\": 123}\n)\n\nprint(response.status_code)\nprint(response.json())\n\n# Call operationId: createUser\nresponse = api.createUser(\n    body={\"name\": \"Bob\"}\n)\n\nprint(response.status_code)\n```",
                     "members": {
                       "spec": {
                         "name": "spec",
@@ -683,7 +683,7 @@
                     "kind": "class",
                     "path": "openapi_first.templates.health_app.main.OpenAPIFirstApp",
                     "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-                    "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+                    "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
                     "members": {
                       "openapi": {
                         "name": "openapi",
@@ -812,7 +812,7 @@
                     "kind": "class",
                     "path": "openapi_first.templates.model_app.main.OpenAPIFirstApp",
                     "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-                    "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+                    "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
                     "members": {
                       "openapi": {
                         "name": "openapi",
@@ -999,7 +999,7 @@
                     "kind": "class",
                     "path": "openapi_first.templates.model_app.test_model_app.OpenAPIClient",
                     "signature": "<bound method Alias.signature of Alias('OpenAPIClient', 'openapi_first.client.OpenAPIClient')>",
-                    "docstring": "OpenAPI-first HTTP client (httpx-based).\n\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation",
+                    "docstring": "OpenAPI-first HTTP client (httpx-based).\n\nThis client derives all callable methods directly from an OpenAPI 3.x\nspecification. Each operationId becomes a method on the client\ninstance.\n\nDesign principles\n-----------------\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation\n- Returns raw httpx.Response objects\n- No response validation or deserialization\n\nParameters\n----------\nspec : dict\n    Parsed OpenAPI 3.x specification.\nbase_url : str | None\n    Base URL of the target service. If omitted, the first entry\n    in the OpenAPI `servers` list is used.\nclient : httpx.Client | None\n    Optional preconfigured httpx client instance.\n\nRaises\n------\nOpenAPIClientError\n    If:\n    - No servers are defined and base_url is not provided\n    - OpenAPI spec has no paths\n    - An operation is missing operationId\n    - Duplicate operationIds are detected\n    - Required path parameters are missing\n    - Required request body is missing\n\n Example\n-------\n```python\nfrom openapi_first import loader, client\n\nspec = loader.load_openapi(\"openapi.yaml\")\n\napi = client.OpenAPIClient(\n    spec=spec,\n    base_url=\"http://localhost:8000\",\n)\n\n# Call operationId: getUser\nresponse = api.getUser(\n    path_params={\"user_id\": 123}\n)\n\nprint(response.status_code)\nprint(response.json())\n\n# Call operationId: createUser\nresponse = api.createUser(\n    body={\"name\": \"Bob\"}\n)\n\nprint(response.status_code)\n```",
                     "members": {
                       "spec": {
                         "name": "spec",

mcp_docs/modules/openapi_first.templates.crud_app.json

@@ -67,7 +67,7 @@
             "kind": "class",
             "path": "openapi_first.templates.crud_app.main.OpenAPIFirstApp",
             "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-            "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+            "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
             "members": {
               "openapi": {
                 "name": "openapi",
@@ -185,7 +185,7 @@
             "kind": "class",
             "path": "openapi_first.templates.crud_app.test_crud_app.OpenAPIClient",
             "signature": "<bound method Alias.signature of Alias('OpenAPIClient', 'openapi_first.client.OpenAPIClient')>",
-            "docstring": "OpenAPI-first HTTP client (httpx-based).\n\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation",
+            "docstring": "OpenAPI-first HTTP client (httpx-based).\n\nThis client derives all callable methods directly from an OpenAPI 3.x\nspecification. Each operationId becomes a method on the client\ninstance.\n\nDesign principles\n-----------------\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation\n- Returns raw httpx.Response objects\n- No response validation or deserialization\n\nParameters\n----------\nspec : dict\n    Parsed OpenAPI 3.x specification.\nbase_url : str | None\n    Base URL of the target service. If omitted, the first entry\n    in the OpenAPI `servers` list is used.\nclient : httpx.Client | None\n    Optional preconfigured httpx client instance.\n\nRaises\n------\nOpenAPIClientError\n    If:\n    - No servers are defined and base_url is not provided\n    - OpenAPI spec has no paths\n    - An operation is missing operationId\n    - Duplicate operationIds are detected\n    - Required path parameters are missing\n    - Required request body is missing\n\n Example\n-------\n```python\nfrom openapi_first import loader, client\n\nspec = loader.load_openapi(\"openapi.yaml\")\n\napi = client.OpenAPIClient(\n    spec=spec,\n    base_url=\"http://localhost:8000\",\n)\n\n# Call operationId: getUser\nresponse = api.getUser(\n    path_params={\"user_id\": 123}\n)\n\nprint(response.status_code)\nprint(response.json())\n\n# Call operationId: createUser\nresponse = api.createUser(\n    body={\"name\": \"Bob\"}\n)\n\nprint(response.status_code)\n```",
             "members": {
               "spec": {
                 "name": "spec",

mcp_docs/modules/openapi_first.templates.crud_app.main.json

@@ -9,7 +9,7 @@
         "kind": "class",
         "path": "openapi_first.templates.crud_app.main.OpenAPIFirstApp",
         "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-        "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+        "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
         "members": {
           "openapi": {
             "name": "openapi",

mcp_docs/modules/openapi_first.templates.crud_app.test_crud_app.json

@@ -30,7 +30,7 @@
         "kind": "class",
         "path": "openapi_first.templates.crud_app.test_crud_app.OpenAPIClient",
         "signature": "<bound method Alias.signature of Alias('OpenAPIClient', 'openapi_first.client.OpenAPIClient')>",
-        "docstring": "OpenAPI-first HTTP client (httpx-based).\n\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation",
+        "docstring": "OpenAPI-first HTTP client (httpx-based).\n\nThis client derives all callable methods directly from an OpenAPI 3.x\nspecification. Each operationId becomes a method on the client\ninstance.\n\nDesign principles\n-----------------\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation\n- Returns raw httpx.Response objects\n- No response validation or deserialization\n\nParameters\n----------\nspec : dict\n    Parsed OpenAPI 3.x specification.\nbase_url : str | None\n    Base URL of the target service. If omitted, the first entry\n    in the OpenAPI `servers` list is used.\nclient : httpx.Client | None\n    Optional preconfigured httpx client instance.\n\nRaises\n------\nOpenAPIClientError\n    If:\n    - No servers are defined and base_url is not provided\n    - OpenAPI spec has no paths\n    - An operation is missing operationId\n    - Duplicate operationIds are detected\n    - Required path parameters are missing\n    - Required request body is missing\n\n Example\n-------\n```python\nfrom openapi_first import loader, client\n\nspec = loader.load_openapi(\"openapi.yaml\")\n\napi = client.OpenAPIClient(\n    spec=spec,\n    base_url=\"http://localhost:8000\",\n)\n\n# Call operationId: getUser\nresponse = api.getUser(\n    path_params={\"user_id\": 123}\n)\n\nprint(response.status_code)\nprint(response.json())\n\n# Call operationId: createUser\nresponse = api.createUser(\n    body={\"name\": \"Bob\"}\n)\n\nprint(response.status_code)\n```",
         "members": {
           "spec": {
             "name": "spec",

mcp_docs/modules/openapi_first.templates.health_app.json

@@ -16,7 +16,7 @@
             "kind": "class",
             "path": "openapi_first.templates.health_app.main.OpenAPIFirstApp",
             "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-            "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+            "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
             "members": {
               "openapi": {
                 "name": "openapi",

mcp_docs/modules/openapi_first.templates.health_app.main.json

@@ -9,7 +9,7 @@
         "kind": "class",
         "path": "openapi_first.templates.health_app.main.OpenAPIFirstApp",
         "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-        "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+        "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
         "members": {
           "openapi": {
             "name": "openapi",

mcp_docs/modules/openapi_first.templates.json

@@ -74,7 +74,7 @@
                 "kind": "class",
                 "path": "openapi_first.templates.crud_app.main.OpenAPIFirstApp",
                 "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-                "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+                "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
                 "members": {
                   "openapi": {
                     "name": "openapi",
@@ -192,7 +192,7 @@
                 "kind": "class",
                 "path": "openapi_first.templates.crud_app.test_crud_app.OpenAPIClient",
                 "signature": "<bound method Alias.signature of Alias('OpenAPIClient', 'openapi_first.client.OpenAPIClient')>",
-                "docstring": "OpenAPI-first HTTP client (httpx-based).\n\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation",
+                "docstring": "OpenAPI-first HTTP client (httpx-based).\n\nThis client derives all callable methods directly from an OpenAPI 3.x\nspecification. Each operationId becomes a method on the client\ninstance.\n\nDesign principles\n-----------------\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation\n- Returns raw httpx.Response objects\n- No response validation or deserialization\n\nParameters\n----------\nspec : dict\n    Parsed OpenAPI 3.x specification.\nbase_url : str | None\n    Base URL of the target service. If omitted, the first entry\n    in the OpenAPI `servers` list is used.\nclient : httpx.Client | None\n    Optional preconfigured httpx client instance.\n\nRaises\n------\nOpenAPIClientError\n    If:\n    - No servers are defined and base_url is not provided\n    - OpenAPI spec has no paths\n    - An operation is missing operationId\n    - Duplicate operationIds are detected\n    - Required path parameters are missing\n    - Required request body is missing\n\n Example\n-------\n```python\nfrom openapi_first import loader, client\n\nspec = loader.load_openapi(\"openapi.yaml\")\n\napi = client.OpenAPIClient(\n    spec=spec,\n    base_url=\"http://localhost:8000\",\n)\n\n# Call operationId: getUser\nresponse = api.getUser(\n    path_params={\"user_id\": 123}\n)\n\nprint(response.status_code)\nprint(response.json())\n\n# Call operationId: createUser\nresponse = api.createUser(\n    body={\"name\": \"Bob\"}\n)\n\nprint(response.status_code)\n```",
                 "members": {
                   "spec": {
                     "name": "spec",
@@ -296,7 +296,7 @@
                 "kind": "class",
                 "path": "openapi_first.templates.health_app.main.OpenAPIFirstApp",
                 "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-                "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+                "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
                 "members": {
                   "openapi": {
                     "name": "openapi",
@@ -425,7 +425,7 @@
                 "kind": "class",
                 "path": "openapi_first.templates.model_app.main.OpenAPIFirstApp",
                 "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-                "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+                "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
                 "members": {
                   "openapi": {
                     "name": "openapi",
@@ -612,7 +612,7 @@
                 "kind": "class",
                 "path": "openapi_first.templates.model_app.test_model_app.OpenAPIClient",
                 "signature": "<bound method Alias.signature of Alias('OpenAPIClient', 'openapi_first.client.OpenAPIClient')>",
-                "docstring": "OpenAPI-first HTTP client (httpx-based).\n\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation",
+                "docstring": "OpenAPI-first HTTP client (httpx-based).\n\nThis client derives all callable methods directly from an OpenAPI 3.x\nspecification. Each operationId becomes a method on the client\ninstance.\n\nDesign principles\n-----------------\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation\n- Returns raw httpx.Response objects\n- No response validation or deserialization\n\nParameters\n----------\nspec : dict\n    Parsed OpenAPI 3.x specification.\nbase_url : str | None\n    Base URL of the target service. If omitted, the first entry\n    in the OpenAPI `servers` list is used.\nclient : httpx.Client | None\n    Optional preconfigured httpx client instance.\n\nRaises\n------\nOpenAPIClientError\n    If:\n    - No servers are defined and base_url is not provided\n    - OpenAPI spec has no paths\n    - An operation is missing operationId\n    - Duplicate operationIds are detected\n    - Required path parameters are missing\n    - Required request body is missing\n\n Example\n-------\n```python\nfrom openapi_first import loader, client\n\nspec = loader.load_openapi(\"openapi.yaml\")\n\napi = client.OpenAPIClient(\n    spec=spec,\n    base_url=\"http://localhost:8000\",\n)\n\n# Call operationId: getUser\nresponse = api.getUser(\n    path_params={\"user_id\": 123}\n)\n\nprint(response.status_code)\nprint(response.json())\n\n# Call operationId: createUser\nresponse = api.createUser(\n    body={\"name\": \"Bob\"}\n)\n\nprint(response.status_code)\n```",
                 "members": {
                   "spec": {
                     "name": "spec",

mcp_docs/modules/openapi_first.templates.model_app.json

@@ -81,7 +81,7 @@
             "kind": "class",
             "path": "openapi_first.templates.model_app.main.OpenAPIFirstApp",
             "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-            "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+            "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
             "members": {
               "openapi": {
                 "name": "openapi",
@@ -268,7 +268,7 @@
             "kind": "class",
             "path": "openapi_first.templates.model_app.test_model_app.OpenAPIClient",
             "signature": "<bound method Alias.signature of Alias('OpenAPIClient', 'openapi_first.client.OpenAPIClient')>",
-            "docstring": "OpenAPI-first HTTP client (httpx-based).\n\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation",
+            "docstring": "OpenAPI-first HTTP client (httpx-based).\n\nThis client derives all callable methods directly from an OpenAPI 3.x\nspecification. Each operationId becomes a method on the client\ninstance.\n\nDesign principles\n-----------------\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation\n- Returns raw httpx.Response objects\n- No response validation or deserialization\n\nParameters\n----------\nspec : dict\n    Parsed OpenAPI 3.x specification.\nbase_url : str | None\n    Base URL of the target service. If omitted, the first entry\n    in the OpenAPI `servers` list is used.\nclient : httpx.Client | None\n    Optional preconfigured httpx client instance.\n\nRaises\n------\nOpenAPIClientError\n    If:\n    - No servers are defined and base_url is not provided\n    - OpenAPI spec has no paths\n    - An operation is missing operationId\n    - Duplicate operationIds are detected\n    - Required path parameters are missing\n    - Required request body is missing\n\n Example\n-------\n```python\nfrom openapi_first import loader, client\n\nspec = loader.load_openapi(\"openapi.yaml\")\n\napi = client.OpenAPIClient(\n    spec=spec,\n    base_url=\"http://localhost:8000\",\n)\n\n# Call operationId: getUser\nresponse = api.getUser(\n    path_params={\"user_id\": 123}\n)\n\nprint(response.status_code)\nprint(response.json())\n\n# Call operationId: createUser\nresponse = api.createUser(\n    body={\"name\": \"Bob\"}\n)\n\nprint(response.status_code)\n```",
             "members": {
               "spec": {
                 "name": "spec",

mcp_docs/modules/openapi_first.templates.model_app.main.json

@@ -9,7 +9,7 @@
         "kind": "class",
         "path": "openapi_first.templates.model_app.main.OpenAPIFirstApp",
         "signature": "<bound method Alias.signature of Alias('OpenAPIFirstApp', 'openapi_first.app.OpenAPIFirstApp')>",
-        "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n>>> from openapi_first import OpenAPIFirstApp\n>>> import app.routes as routes\n>>>\n>>> app = OpenAPIFirstApp(\n...     openapi_path=\"app/openapi.json\",\n...     routes_module=routes,\n...     title=\"Example Service\"\n... )",
+        "docstring": "FastAPI application enforcing OpenAPI-first design.\n\n`OpenAPIFirstApp` subclasses FastAPI and replaces manual route\nregistration with OpenAPI-driven binding. All routes are derived\nfrom the provided OpenAPI specification, and each operationId is\nmapped to a Python function in the supplied routes module.\n\nParameters\n----------\nopenapi_path : str\n    Filesystem path to the OpenAPI 3.x specification file.\n    This specification is treated as the authoritative API contract.\n\nroutes_module : module\n    Python module containing handler functions whose names correspond\n    exactly to OpenAPI operationId values.\n\n**fastapi_kwargs\n    Additional keyword arguments passed directly to `fastapi.FastAPI`\n    (e.g., title, version, middleware, lifespan handlers).\n\nRaises\n------\nOpenAPIFirstError\n    If the OpenAPI specification is invalid, or if any declared\n    operationId does not have a corresponding handler function.\n\nBehavior guarantees\n-------------------\n- No route can exist without an OpenAPI declaration.\n- No OpenAPI operation can exist without a handler.\n- Swagger UI and `/openapi.json` always reflect the provided spec.\n- Handler functions remain framework-agnostic and testable.\n\nExample\n-------\n```python\nfrom openapi_first import OpenAPIFirstApp\nimport app.routes as routes\n\napp = OpenAPIFirstApp(\n    openapi_path=\"app/openapi.json\",\n    routes_module=routes,\n    title=\"Example Service\",\n)\n```",
         "members": {
           "openapi": {
             "name": "openapi",

mcp_docs/modules/openapi_first.templates.model_app.test_model_app.json

@@ -30,7 +30,7 @@
         "kind": "class",
         "path": "openapi_first.templates.model_app.test_model_app.OpenAPIClient",
         "signature": "<bound method Alias.signature of Alias('OpenAPIClient', 'openapi_first.client.OpenAPIClient')>",
-        "docstring": "OpenAPI-first HTTP client (httpx-based).\n\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation",
+        "docstring": "OpenAPI-first HTTP client (httpx-based).\n\nThis client derives all callable methods directly from an OpenAPI 3.x\nspecification. Each operationId becomes a method on the client\ninstance.\n\nDesign principles\n-----------------\n- One callable per operationId\n- Explicit parameters (path, query, headers, body)\n- No implicit schema inference or mutation\n- Returns raw httpx.Response objects\n- No response validation or deserialization\n\nParameters\n----------\nspec : dict\n    Parsed OpenAPI 3.x specification.\nbase_url : str | None\n    Base URL of the target service. If omitted, the first entry\n    in the OpenAPI `servers` list is used.\nclient : httpx.Client | None\n    Optional preconfigured httpx client instance.\n\nRaises\n------\nOpenAPIClientError\n    If:\n    - No servers are defined and base_url is not provided\n    - OpenAPI spec has no paths\n    - An operation is missing operationId\n    - Duplicate operationIds are detected\n    - Required path parameters are missing\n    - Required request body is missing\n\n Example\n-------\n```python\nfrom openapi_first import loader, client\n\nspec = loader.load_openapi(\"openapi.yaml\")\n\napi = client.OpenAPIClient(\n    spec=spec,\n    base_url=\"http://localhost:8000\",\n)\n\n# Call operationId: getUser\nresponse = api.getUser(\n    path_params={\"user_id\": 123}\n)\n\nprint(response.status_code)\nprint(response.json())\n\n# Call operationId: createUser\nresponse = api.createUser(\n    body={\"name\": \"Bob\"}\n)\n\nprint(response.status_code)\n```",
         "members": {
           "spec": {
             "name": "spec",

openapi_first/app.py

@@ -84,14 +84,16 @@ class OpenAPIFirstApp(FastAPI):
 
     Example
     -------
-    >>> from openapi_first import OpenAPIFirstApp
+    ```python
-    >>> import app.routes as routes
+    from openapi_first import OpenAPIFirstApp
-    >>>
+    import app.routes as routes
-    >>> app = OpenAPIFirstApp(
+
-    ...     openapi_path="app/openapi.json",
+    app = OpenAPIFirstApp(
-    ...     routes_module=routes,
+        openapi_path="app/openapi.json",
-    ...     title="Example Service"
+        routes_module=routes,
-    ... )
+        title="Example Service",
+    )
+    ```
     """
 
     def __init__(

openapi_first/client.py

@@ -1,3 +1,61 @@
+"""
+openapi_first.client
+====================
+
+OpenAPI-first HTTP client for contract-driven services.
+
+This module provides `OpenAPIClient`, a thin, strict HTTP client that
+derives all callable operations directly from an OpenAPI 3.x specification.
+
+It is the client counterpart to `OpenAPIFirstApp`.
+
+Core principles
+---------------
+- The OpenAPI specification is the single source of truth.
+- Each operationId becomes a callable Python method.
+- No implicit schema mutation or inference.
+- No code generation step.
+- Minimal abstraction over httpx.
+
+What this module does
+---------------------
+- Parses an OpenAPI 3.x specification.
+- Dynamically creates one callable per operationId.
+- Enforces presence of:
+  - servers
+  - paths
+  - operationId
+- Formats path parameters safely.
+- Handles JSON request bodies explicitly.
+- Returns raw `httpx.Response` objects.
+
+What this module does NOT do
+----------------------------
+- It does not generate client code.
+- It does not validate request/response schemas.
+- It does not deserialize responses.
+- It does not retry requests.
+- It does not implement authentication helpers.
+- It does not assume non-2xx responses are failures.
+
+Intended usage
+--------------
+This client is designed for:
+
+- Service-to-service communication
+- Integration testing
+- Contract-driven internal SDK usage
+- Systems that want OpenAPI-first symmetry with `OpenAPIFirstApp`
+
+Design constraints
+------------------
+- Only the first server in the OpenAPI `servers` list is used if
+  `base_url` is not explicitly provided.
+- Only explicitly declared request bodies are allowed.
+- `application/json` is handled natively; other media types are sent as raw content.
+- All responses are returned as-is.
+"""
+
 from typing import Any, Callable, Dict, Optional
 from urllib.parse import urljoin
 
@@ -14,9 +72,66 @@ class OpenAPIClient:
     """
     OpenAPI-first HTTP client (httpx-based).
 
+    This client derives all callable methods directly from an OpenAPI 3.x
+    specification. Each operationId becomes a method on the client
+    instance.
+
+    Design principles
+    -----------------
     - One callable per operationId
     - Explicit parameters (path, query, headers, body)
     - No implicit schema inference or mutation
+    - Returns raw httpx.Response objects
+    - No response validation or deserialization
+
+    Parameters
+    ----------
+    spec : dict
+        Parsed OpenAPI 3.x specification.
+    base_url : str | None
+        Base URL of the target service. If omitted, the first entry
+        in the OpenAPI `servers` list is used.
+    client : httpx.Client | None
+        Optional preconfigured httpx client instance.
+
+    Raises
+    ------
+    OpenAPIClientError
+        If:
+        - No servers are defined and base_url is not provided
+        - OpenAPI spec has no paths
+        - An operation is missing operationId
+        - Duplicate operationIds are detected
+        - Required path parameters are missing
+        - Required request body is missing
+
+     Example
+    -------
+    ```python
+    from openapi_first import loader, client
+
+    spec = loader.load_openapi("openapi.yaml")
+
+    api = client.OpenAPIClient(
+        spec=spec,
+        base_url="http://localhost:8000",
+    )
+
+    # Call operationId: getUser
+    response = api.getUser(
+        path_params={"user_id": 123}
+    )
+
+    print(response.status_code)
+    print(response.json())
+
+    # Call operationId: createUser
+    response = api.createUser(
+        body={"name": "Bob"}
+    )
+
+    print(response.status_code)
+    ```
     """
 
     def __init__(