diff --git a/pyproject.toml b/pyproject.toml
index bff67093..ca73b6e4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,7 @@ authors = [
 dependencies = [
     "prefect>=3.0",
     "jinja2>=3.1.4",
-    "langchain_core>=0.2.9",
+    "langchain_core>=0.2,<0.3",
     "langchain_openai>=0.1.8",
     "langchain-anthropic>=0.1.19",
     "markdownify>=0.12.1",
@@ -82,7 +82,7 @@ managed = true
 # ruff configuration
 [tool.ruff]
 target-version = "py311"
-lint.extend-select = ["I"]
+lint.select = ["I"]                                               # Changed from lint.extend-select to select
 lint.dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$" # default, but here in case we want to change it
 
 [tool.ruff.format]
diff --git a/src/controlflow/agents/agent.py b/src/controlflow/agents/agent.py
index 0b391950..d11abe47 100644
--- a/src/controlflow/agents/agent.py
+++ b/src/controlflow/agents/agent.py
@@ -298,7 +298,6 @@ def _run_model(
             response: AIMessage = model.invoke(messages)
 
         yield AgentMessage(agent=self, message=response)
-
         create_markdown_artifact(
             markdown=f"""
 {response.content or '(No content)'}