diff --git a/.gitignore b/.gitignore
index 4c2a407..5388b5b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -98,7 +98,7 @@ typings/
 Thumbs.db
 
 # Ignore built ts files
-__tests__/runner/*
+tests/runner/*
 
 # IDE files
 .idea
diff --git a/AGENTS.md b/AGENTS.md
index 69e0270..1af6f8f 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -35,7 +35,7 @@ npm run package       # Build src/index.ts -> dist/index.js via Rollup
 npm run bundle        # Alias: format + package
 
 # Run a single test file
-NODE_OPTIONS=--experimental-vm-modules NODE_NO_WARNINGS=1 npx jest __tests__/main.test.ts
+NODE_OPTIONS=--experimental-vm-modules NODE_NO_WARNINGS=1 npx jest tests/main.test.ts
 
 # CI variants (suppress warnings)
 npm run ci-test       # Run tests in CI mode
@@ -65,7 +65,7 @@ npm run package:watch # Auto-rebuild on changes
   - `processTag()`: Creates/updates individual tags based on `when_exists` mode
   - `resolveRefToSha()`: Converts git refs to commit SHAs (private helper)
 - **[action.yml](action.yml)**: GitHub Action metadata (inputs/outputs)
-- **[\_\_fixtures\_\_/](__fixtures__)**: Mock implementations of @actions/core,
+- **[tests/fixtures/](tests/fixtures)**: Mock implementations of @actions/core,
   @actions/github, and csv-parse for testing
 
 ### Tag Input Parsing
@@ -97,12 +97,12 @@ jest.unstable_mockModule('@actions/core', () => core)
 const { run } = await import('../src/main.ts')
 ```
 
-Mock fixtures live in `__fixtures__/` (e.g., `core.ts` mocks @actions/core).
+Mock fixtures live in `tests/fixtures/` (e.g., `core.ts` mocks @actions/core).
 
 ### Testing Best Practices
 
 - Consider edge cases as well as the main success path
-- Tests live in `__tests__/` directory, fixtures in `__fixtures__/`
+- Tests live in `tests/` directory, fixtures in `tests/fixtures/`
 - Run tests after any refactoring to ensure coverage requirements are met
 - Use `@actions/core` package for logging (not `console`) for GitHub Actions
   compatibility
diff --git a/__fixtures__/core.ts b/tests/fixtures/core.ts
similarity index 100%
rename from __fixtures__/core.ts
rename to tests/fixtures/core.ts
diff --git a/__fixtures__/csv-parse.ts b/tests/fixtures/csv-parse.ts
similarity index 100%
rename from __fixtures__/csv-parse.ts
rename to tests/fixtures/csv-parse.ts
diff --git a/__fixtures__/github.ts b/tests/fixtures/github.ts
similarity index 100%
rename from __fixtures__/github.ts
rename to tests/fixtures/github.ts
diff --git a/__tests__/main.test.ts b/tests/main.test.ts
similarity index 99%
rename from __tests__/main.test.ts
rename to tests/main.test.ts
index 0a06294..d16090e 100644
--- a/__tests__/main.test.ts
+++ b/tests/main.test.ts
@@ -2,9 +2,9 @@
  * Unit tests for the action's main functionality, src/main.ts
  */
 import { jest } from '@jest/globals'
-import * as core from '../__fixtures__/core.js'
-import * as github from '../__fixtures__/github.js'
-import * as csvParse from '../__fixtures__/csv-parse.js'
+import * as core from './fixtures/core.js'
+import * as github from './fixtures/github.js'
+import * as csvParse from './fixtures/csv-parse.js'
 
 // Mocks should be declared before the module being tested is imported.
 jest.unstable_mockModule('@actions/core', () => core)
diff --git a/tsconfig.eslint.json b/tsconfig.eslint.json
index 7a00c40..219fb6d 100644
--- a/tsconfig.eslint.json
+++ b/tsconfig.eslint.json
@@ -7,8 +7,7 @@
   },
   "exclude": ["dist", "node_modules"],
   "include": [
-    "__fixtures__",
-    "__tests__",
+    "tests",
     "src",
     "eslint.config.mjs",
     "jest.config.js",
diff --git a/tsconfig.json b/tsconfig.json
index b65a760..ac52c83 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -6,6 +6,6 @@
     "moduleResolution": "NodeNext",
     "outDir": "./dist"
   },
-  "exclude": ["__fixtures__", "__tests__", "coverage", "dist", "node_modules"],
+  "exclude": ["tests", "coverage", "dist", "node_modules"],
   "include": ["src"]
 }