diff --git a/pyproject.toml b/pyproject.toml
index 6232fea..bd06302 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,7 +21,7 @@ classifiers = [
 dependencies = [
     # LangGraph for agent orchestration (Constitution: State)
     "langgraph>=0.2.0,<2.0.0",
-    "langchain-core>=0.3.0,<2.0.0",
+    "langchain-core>=1.3.3,<2.0.0",
     "langchain-openai>=0.2.0,<2.0.0",
     # OpenAI for LLM (Research Decision #6)
     "openai>=1.50.0,<3.0.0",
diff --git a/uv.lock b/uv.lock
index ab0b364..90829ab 100644
--- a/uv.lock
+++ b/uv.lock
@@ -102,7 +102,7 @@ requires-dist = [
     { name = "google-auth", specifier = ">=2.28.0,<3.0.0" },
     { name = "httpx", specifier = ">=0.28.0,<1.0.0" },
     { name = "jsonschema", specifier = ">=4.20.0,<5.0.0" },
-    { name = "langchain-core", specifier = ">=0.3.0,<2.0.0" },
+    { name = "langchain-core", specifier = ">=1.3.3,<2.0.0" },
     { name = "langchain-google-genai", specifier = ">=4.2.0,<5.0.0" },
     { name = "langchain-openai", specifier = ">=0.2.0,<2.0.0" },
     { name = "langgraph", specifier = ">=0.2.0,<2.0.0" },
@@ -1613,10 +1613,11 @@ wheels = [
 
 [[package]]
 name = "langchain-core"
-version = "1.2.11"
+version = "1.3.3"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "jsonpatch" },
+    { name = "langchain-protocol" },
     { name = "langsmith" },
     { name = "packaging" },
     { name = "pydantic" },
@@ -1625,9 +1626,9 @@ dependencies = [
     { name = "typing-extensions" },
     { name = "uuid-utils" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/12/17/1943cedfc118e04b8128e4c3e1dbf0fa0ea58eefddbb6198cfd699d19f01/langchain_core-1.2.11.tar.gz", hash = "sha256:f164bb36602dd74a3a50c1334fca75309ad5ed95767acdfdbb9fa95ce28a1e01", size = 831211, upload-time = "2026-02-10T20:35:28.35Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/d3/ae/8b74458fc3850ec3d150eb9f45e857db129dafa801fb5cf173dfc9f8bbf3/langchain_core-1.3.3.tar.gz", hash = "sha256:fa510a5db8efdc0c6ff41c0939fb5c00a0183c11f6b84233e892e3227ff69182", size = 915041, upload-time = "2026-05-05T19:02:36.612Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/10/30/1f80e3fc674353cad975ed5294353d42512535d2094ef032c06454c2c873/langchain_core-1.2.11-py3-none-any.whl", hash = "sha256:ae11ceb8dda60d0b9d09e763116e592f1683327c17be5b715f350fd29aee65d3", size = 500062, upload-time = "2026-02-10T20:35:26.698Z" },
+    { url = "https://files.pythonhosted.org/packages/1f/01/4771b7ab2af1d1aba5b710bd8f13d9225c609425214b357590a17b01be77/langchain_core-1.3.3-py3-none-any.whl", hash = "sha256:18aae8506f37da7f74398492279a7d6efcee4f8e23c4c41c7af080eeb7ef7bd1", size = 543857, upload-time = "2026-05-05T19:02:34.52Z" },
 ]
 
 [[package]]
@@ -1659,6 +1660,18 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/64/a1/50e7596aca775d8c3883eceeaf47489fac26c57c1abe243c00174f715a8a/langchain_openai-1.1.7-py3-none-any.whl", hash = "sha256:34e9cd686aac1a120d6472804422792bf8080a2103b5d21ee450c9e42d053815", size = 84753, upload-time = "2026-01-07T19:44:58.629Z" },
 ]
 
+[[package]]
+name = "langchain-protocol"
+version = "0.0.15"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "typing-extensions" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/4f/24/9777489d6fbbee64af0c8f96d4f840239c408cf694f3394672807dafc490/langchain_protocol-0.0.15.tar.gz", hash = "sha256:9ab2d11ee73944754f10e037e717098d3a6796f0e58afa9cadda6154e7655ade", size = 5862, upload-time = "2026-05-01T22:30:04.748Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/1d/7a/9c97a7b9cbe4c5dc6a44cdb1545450c28f0c8ce89b9c1f0ee7fbad896263/langchain_protocol-0.0.15-py3-none-any.whl", hash = "sha256:461eb794358f83d5e42635a5797799ffec7b4702314e34edf73ac21e75d3ef79", size = 6982, upload-time = "2026-05-01T22:30:03.877Z" },
+]
+
 [[package]]
 name = "langgraph"
 version = "1.0.7"