From 7be296f12ed5977b9edff62f79d2884fb3b3666d Mon Sep 17 00:00:00 2001
From: blois <pete@anthropic.com>
Date: Thu, 30 Oct 2025 15:14:42 -0700
Subject: [PATCH] feat: add max_thinking_tokens option to ClaudeAgentOptions
 (#298)
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Add support for controlling the maximum number of tokens allocated to
extended thinking blocks via the max_thinking_tokens parameter.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude <noreply@anthropic.com>
---
 .gitignore                                            |  1 +
 .../_internal/transport/subprocess_cli.py             |  5 +++++
 src/claude_agent_sdk/types.py                         |  2 ++
 tests/test_transport.py                               | 11 +++++++++++
 4 files changed, 19 insertions(+)

diff --git a/.gitignore b/.gitignore
index 7e6d2df..6be5cc4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,6 +26,7 @@ venv/
 ENV/
 env/
 .venv
+uv.lock
 
 # IDEs
 .vscode/
diff --git a/src/claude_agent_sdk/_internal/transport/subprocess_cli.py b/src/claude_agent_sdk/_internal/transport/subprocess_cli.py
index 1ec352f..ac0ac83 100644
--- a/src/claude_agent_sdk/_internal/transport/subprocess_cli.py
+++ b/src/claude_agent_sdk/_internal/transport/subprocess_cli.py
@@ -216,6 +216,11 @@ class SubprocessCLITransport(Transport):
             # String mode: use --print with the prompt
             cmd.extend(["--print", "--", str(self._prompt)])
 
+        if self._options.max_thinking_tokens is not None:
+            cmd.extend(
+                ["--max-thinking-tokens", str(self._options.max_thinking_tokens)]
+            )
+
         # Check if command line is too long (Windows limitation)
         cmd_str = " ".join(cmd)
         if len(cmd_str) > _CMD_LENGTH_LIMIT and self._options.agents:
diff --git a/src/claude_agent_sdk/types.py b/src/claude_agent_sdk/types.py
index efeaf70..bb551d0 100644
--- a/src/claude_agent_sdk/types.py
+++ b/src/claude_agent_sdk/types.py
@@ -554,6 +554,8 @@ class ClaudeAgentOptions:
     setting_sources: list[SettingSource] | None = None
     # Plugin configurations for custom plugins
     plugins: list[SdkPluginConfig] = field(default_factory=list)
+    # Max tokens for thinking blocks
+    max_thinking_tokens: int | None = None
 
 
 # SDK Control Protocol
diff --git a/tests/test_transport.py b/tests/test_transport.py
index f23dcbf..00ccd90 100644
--- a/tests/test_transport.py
+++ b/tests/test_transport.py
@@ -129,6 +129,17 @@ class TestSubprocessCLITransport:
         assert "--max-turns" in cmd
         assert "5" in cmd
 
+    def test_build_command_with_max_thinking_tokens(self):
+        """Test building CLI command with max_thinking_tokens option."""
+        transport = SubprocessCLITransport(
+            prompt="test",
+            options=make_options(max_thinking_tokens=5000),
+        )
+
+        cmd = transport._build_command()
+        assert "--max-thinking-tokens" in cmd
+        assert "5000" in cmd
+
     def test_build_command_with_add_dirs(self):
         """Test building CLI command with add_dirs option."""
         from pathlib import Path