From eb350281c9eb2ec909c2be4c731ae9737211846f Mon Sep 17 00:00:00 2001
From: Koudai Aono <koxudaxi@gmail.com>
Date: Sat, 3 Jan 2026 05:55:07 +0000
Subject: [PATCH 1/2] Add deprecation warning and explicit --output-model-type
 to docs

---
 docs/aliases.md    |  6 +++++-
 docs/formatting.md | 23 +++++++++++++++++++----
 docs/graphql.md    | 20 +++++++++++++++++---
 docs/index.md      |  8 ++++++++
 docs/jsondata.md   |  6 +++++-
 docs/jsonschema.md |  6 +++++-
 6 files changed, 59 insertions(+), 10 deletions(-)

diff --git a/docs/aliases.md b/docs/aliases.md
index 0904708c0..742331be9 100644
--- a/docs/aliases.md
+++ b/docs/aliases.md
@@ -7,7 +7,11 @@ The `--aliases` option allows you to rename fields in the generated models. This
 ## 🚀 Basic Usage
 
 ```bash
-datamodel-codegen --input schema.json --output model.py --aliases aliases.json
+datamodel-codegen \
+    --input schema.json \
+    --output-model-type pydantic_v2.BaseModel \
+    --output model.py \
+    --aliases aliases.json
 ```
 
 ## 📋 Alias File Format
diff --git a/docs/formatting.md b/docs/formatting.md
index f04bbe8c8..37c0b7e6f 100644
--- a/docs/formatting.md
+++ b/docs/formatting.md
@@ -15,7 +15,10 @@ Generated code is automatically formatted using code formatters. By default, `bl
     **Library users**: Explicitly pass `formatters=[Formatter.BLACK, Formatter.ISORT]` to suppress this warning.
 
 ```bash
-datamodel-codegen --input schema.yaml --output model.py
+datamodel-codegen \
+    --input schema.yaml \
+    --output-model-type pydantic_v2.BaseModel \
+    --output model.py
 ```
 
 This runs the following formatters in order:
@@ -44,10 +47,18 @@ This runs the following formatters in order:
 
 ```bash
 # Use ruff for both linting and formatting
-datamodel-codegen --formatters ruff-check ruff-format --input schema.yaml --output model.py
+datamodel-codegen \
+    --formatters ruff-check ruff-format \
+    --input schema.yaml \
+    --output-model-type pydantic_v2.BaseModel \
+    --output model.py
 
 # Use ruff-format as a black replacement
-datamodel-codegen --formatters isort ruff-format --input schema.yaml --output model.py
+datamodel-codegen \
+    --formatters isort ruff-format \
+    --input schema.yaml \
+    --output-model-type pydantic_v2.BaseModel \
+    --output model.py
 ```
 
 ### 🚫 Disable formatting
@@ -91,7 +102,11 @@ quote-style = "single"
 By default, string quote style is determined by your formatter configuration. To force double quotes regardless of configuration:
 
 ```bash
-datamodel-codegen --use-double-quotes --input schema.yaml --output model.py
+datamodel-codegen \
+    --use-double-quotes \
+    --input schema.yaml \
+    --output-model-type pydantic_v2.BaseModel \
+    --output model.py
 ```
 
 This overrides `skip_string_normalization` in black config.
diff --git a/docs/graphql.md b/docs/graphql.md
index 2e85e9002..48b168657 100644
--- a/docs/graphql.md
+++ b/docs/graphql.md
@@ -5,7 +5,11 @@ Generate Pydantic models from GraphQL schema definitions.
 ## 🚀 Quick Start
 
 ```bash
-datamodel-codegen --input schema.graphql --input-file-type graphql --output model.py
+datamodel-codegen \
+    --input schema.graphql \
+    --input-file-type graphql \
+    --output-model-type pydantic_v2.BaseModel \
+    --output model.py
 ```
 
 !!! note "📦 Installation"
@@ -148,7 +152,12 @@ print(books)
 ## 🎨 Custom Scalar Types
 
 ```bash
-datamodel-codegen --input schema.graphql --input-file-type graphql --output model.py --extra-template-data data.json
+datamodel-codegen \
+    --input schema.graphql \
+    --input-file-type graphql \
+    --output-model-type pydantic_v2.BaseModel \
+    --extra-template-data data.json \
+    --output model.py
 ```
 
 **schema.graphql**
@@ -215,7 +224,12 @@ as GraphQL servers typically don't expect this field in input data.
 Use the `--graphql-no-typename` option to exclude this field:
 
 ```bash
-datamodel-codegen --input schema.graphql --input-file-type graphql --output model.py --graphql-no-typename
+datamodel-codegen \
+    --input schema.graphql \
+    --input-file-type graphql \
+    --output-model-type pydantic_v2.BaseModel \
+    --graphql-no-typename \
+    --output model.py
 ```
 
 **Before (default):**
diff --git a/docs/index.md b/docs/index.md
index 481f83f3e..32327e9d3 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -63,6 +63,14 @@
 
 ---
 
+!!! warning "Omitting --output-model-type is deprecated"
+    Starting from version 0.53.0, omitting `--output-model-type` is deprecated.
+    The implicit default `pydantic.BaseModel` (Pydantic v1) will be removed in a future version.
+
+    We recommend using `--output-model-type pydantic_v2.BaseModel` for new projects.
+
+---
+
 ## 🏃 Quick Start
 
 ### 1️⃣ Create a schema file
diff --git a/docs/jsondata.md b/docs/jsondata.md
index 01c7c93c3..f606f85af 100644
--- a/docs/jsondata.md
+++ b/docs/jsondata.md
@@ -5,7 +5,11 @@ Generate Pydantic models directly from JSON data. Under the hood, the generator
 ## 🚀 Quick Start
 
 ```bash
-datamodel-codegen --input pets.json --input-file-type json --output model.py
+datamodel-codegen \
+    --input pets.json \
+    --input-file-type json \
+    --output-model-type pydantic_v2.BaseModel \
+    --output model.py
 ```
 
 ## 📝 Example
diff --git a/docs/jsonschema.md b/docs/jsonschema.md
index 3d25ba187..0a124c92a 100644
--- a/docs/jsonschema.md
+++ b/docs/jsonschema.md
@@ -5,7 +5,11 @@ Generate Pydantic models from JSON Schema definitions. See [Supported Data Types
 ## 🚀 Quick Start
 
 ```bash
-datamodel-codegen --input person.json --input-file-type jsonschema --output model.py
+datamodel-codegen \
+    --input person.json \
+    --input-file-type jsonschema \
+    --output-model-type pydantic_v2.BaseModel \
+    --output model.py
 ```
 
 ## 📝 Example

From 61cb2c62d86932f92853e197569bec3c5978e882 Mon Sep 17 00:00:00 2001
From: Koudai Aono <koxudaxi@gmail.com>
Date: Sat, 3 Jan 2026 07:17:56 +0000
Subject: [PATCH 2/2] Add note explaining --output-model-type recommendation

---
 docs/graphql.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/docs/graphql.md b/docs/graphql.md
index 48b168657..7dcc47851 100644
--- a/docs/graphql.md
+++ b/docs/graphql.md
@@ -12,6 +12,10 @@ datamodel-codegen \
     --output model.py
 ```
 
+!!! tip "Why `--output-model-type`?"
+    Starting from version 0.53.0, explicitly specifying `--output-model-type` is recommended.
+    See [Omitting --output-model-type is deprecated](index.md#omitting---output-model-type-is-deprecated) for details.
+
 !!! note "📦 Installation"
     GraphQL support requires the `graphql` extra:
     ```bash