diff --git a/src/celeste/modalities/text/providers/deepseek/models.py b/src/celeste/modalities/text/providers/deepseek/models.py
index 39693086..fb4a9eff 100644
--- a/src/celeste/modalities/text/providers/deepseek/models.py
+++ b/src/celeste/modalities/text/providers/deepseek/models.py
@@ -1,6 +1,6 @@
 """DeepSeek models for text modality."""
 
-from celeste.constraints import Range, Schema, ToolChoiceSupport, ToolSupport
+from celeste.constraints import Choice, Range, Schema, ToolChoiceSupport, ToolSupport
 from celeste.core import Modality, Operation, Parameter, Provider
 from celeste.models import Model
 
@@ -33,4 +33,34 @@
             TextParameter.OUTPUT_SCHEMA: Schema(),
         },
     ),
+    Model(
+        id="deepseek-v4-flash",
+        provider=Provider.DEEPSEEK,
+        display_name="DeepSeek V4 Flash",
+        operations={Modality.TEXT: {Operation.GENERATE}},
+        streaming=True,
+        parameter_constraints={
+            Parameter.TEMPERATURE: Range(min=0.0, max=2.0, step=0.01),
+            Parameter.MAX_TOKENS: Range(min=1, max=384_000, step=1),
+            TextParameter.THINKING_LEVEL: Choice(options=["disabled", "high", "max"]),
+            TextParameter.OUTPUT_SCHEMA: Schema(),
+            TextParameter.TOOLS: ToolSupport(tools=[]),
+            TextParameter.TOOL_CHOICE: ToolChoiceSupport(),
+        },
+    ),
+    Model(
+        id="deepseek-v4-pro",
+        provider=Provider.DEEPSEEK,
+        display_name="DeepSeek V4 Pro",
+        operations={Modality.TEXT: {Operation.GENERATE}},
+        streaming=True,
+        parameter_constraints={
+            Parameter.TEMPERATURE: Range(min=0.0, max=2.0, step=0.01),
+            Parameter.MAX_TOKENS: Range(min=1, max=384_000, step=1),
+            TextParameter.THINKING_LEVEL: Choice(options=["disabled", "high", "max"]),
+            TextParameter.OUTPUT_SCHEMA: Schema(),
+            TextParameter.TOOLS: ToolSupport(tools=[]),
+            TextParameter.TOOL_CHOICE: ToolChoiceSupport(),
+        },
+    ),
 ]
diff --git a/src/celeste/modalities/text/providers/deepseek/parameters.py b/src/celeste/modalities/text/providers/deepseek/parameters.py
index 2dcb360b..8587f656 100644
--- a/src/celeste/modalities/text/providers/deepseek/parameters.py
+++ b/src/celeste/modalities/text/providers/deepseek/parameters.py
@@ -1,7 +1,24 @@
 """DeepSeek parameter mappers for text."""
 
+from celeste.parameters import ParameterMapper
+from celeste.providers.deepseek.chat.parameters import (
+    ThinkingLevelMapper as _ThinkingLevelMapper,
+)
+from celeste.types import TextContent
+
+from ...parameters import TextParameter
 from ...protocols.chatcompletions.parameters import CHATCOMPLETIONS_PARAMETER_MAPPERS
 
-DEEPSEEK_PARAMETER_MAPPERS = CHATCOMPLETIONS_PARAMETER_MAPPERS
+
+class ThinkingLevelMapper(_ThinkingLevelMapper):
+    """Map thinking_level to DeepSeek's thinking/reasoning_effort fields."""
+
+    name = TextParameter.THINKING_LEVEL
+
+
+DEEPSEEK_PARAMETER_MAPPERS: list[ParameterMapper[TextContent]] = [
+    *CHATCOMPLETIONS_PARAMETER_MAPPERS,
+    ThinkingLevelMapper(),
+]
 
 __all__ = ["DEEPSEEK_PARAMETER_MAPPERS"]
diff --git a/src/celeste/providers/deepseek/chat/parameters.py b/src/celeste/providers/deepseek/chat/parameters.py
new file mode 100644
index 00000000..b47ce4c6
--- /dev/null
+++ b/src/celeste/providers/deepseek/chat/parameters.py
@@ -0,0 +1,35 @@
+"""DeepSeek Chat API parameter mappers."""
+
+from typing import Any
+
+from celeste.models import Model
+from celeste.parameters import ParameterMapper
+from celeste.types import TextContent
+
+
+class ThinkingLevelMapper(ParameterMapper[TextContent]):
+    """Map thinking_level to DeepSeek's thinking + reasoning_effort fields.
+
+    - "disabled" → thinking={"type": "disabled"}
+    - "high"     → thinking={"type": "enabled"}, reasoning_effort="high"
+    - "max"      → thinking={"type": "enabled"}, reasoning_effort="max"
+    """
+
+    def map(
+        self,
+        request: dict[str, Any],
+        value: object,
+        model: Model,
+    ) -> dict[str, Any]:
+        validated_value = self._validate_value(value, model)
+        if validated_value is None:
+            return request
+        if validated_value == "disabled":
+            request["thinking"] = {"type": "disabled"}
+        else:
+            request["thinking"] = {"type": "enabled"}
+            request["reasoning_effort"] = validated_value
+        return request
+
+
+__all__ = ["ThinkingLevelMapper"]