fix(deps): require mcp>=1.19.0 for CallToolResult handler returns

create_sdk_mcp_server tool handlers return CallToolResult objects since
v0.1.51 (PR #717). mcp<1.19.0 cannot handle this return type from
@server.call_tool() decorated functions — it falls through the iterable
branch, fails pydantic validation, and silently swallows the tool output
into an error result.

Users upgrading claude-agent-sdk in an existing env with old mcp would
see in-process SDK MCP tools run but return validation error blobs
instead of actual results.

Author: qing-ant

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## 0.1.70
+
+### Bug Fixes
+
+- Bumped minimum `mcp` dependency to `>=1.19.0`. Older versions cannot handle `CallToolResult` returns from in-process SDK MCP tool handlers (introduced in v0.1.51), causing tool results to be silently replaced with a pydantic validation error.
+
 ## 0.1.69
 
 ### Documentation

pyproject.toml

@@ -28,7 +28,7 @@ dependencies = [
     "anyio>=4.0.0",
     "sniffio>=1.0.0",
     "typing_extensions>=4.0.0; python_version<'3.11'",
-    "mcp>=0.1.0",
+    "mcp>=1.19.0",
 ]
 
 [project.optional-dependencies]