diff --git a/pyproject.toml b/pyproject.toml
index 7b09f24..78b2db4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -32,7 +32,7 @@ dependencies = [
 anthropic = ["anthropic>=0.25"]
 openai    = ["openai>=1.0"]
 all       = ["anthropic>=0.25", "openai>=1.0"]
-dev       = ["pytest>=8.0", "pytest-cov>=5.0", "anthropic>=0.25", "openai>=1.0", "types-PyYAML>=6.0"]
+dev       = ["pytest>=8.0", "pytest-cov>=5.0", "anthropic>=0.25", "openai>=1.0", "types-PyYAML>=6.0", "ruff>=0.4", "mypy>=1.10"]
 
 [project.scripts]
 prompt = "prompt_run.cli:cli"
@@ -55,6 +55,9 @@ testpaths = ["tests"]
 [tool.mypy]
 python_version = "3.11"
 strict = true
+# platform-specific optional-dependency stubs may or may not suppress errors;
+# avoid CI failures caused by "unused ignore" differences across OS/versions
+warn_unused_ignores = false
 
 [tool.ruff]
 line-length = 100