docs(grep): fix malformed glob examples

src/fastcontext/agent/tool/grep.md

@@ -2,7 +2,7 @@ A powerful search tool built on ripgrep
 Usage:
 - Prefer using Grep for search tasks when you know the exact symbols or strings to search for. Whenever possible, use this tool instead of invoking grep or rg as a terminal command.
 - Supports full regex syntax (e.g., "log.*Error", "function\s+\w+")
-- Filter files with glob parameter (e.g., ".js", "**/.tsx") or type parameter (e.g., "js", "py", "rust")
+- Filter files with glob parameter (e.g., "*.js", "**/*.tsx") or type parameter (e.g., "js", "py", "rust")
 - Output modes: "content" shows matching lines (default), "files_with_matches" shows only file paths, "count" shows match counts
 - Pattern syntax: Uses ripgrep (not grep) - literal braces need escaping (use interface\{\} to find interface{} in Go code)
 - Multiline matching: By default patterns match within single lines only. For cross-line patterns like struct \{[\s\S]*?field, use multiline: true

tests/test_grep_glob_examples.py

@@ -0,0 +1,30 @@
+import asyncio
+import json
+import tempfile
+from pathlib import Path
+
+from fastcontext.agent.tool.glob import GlobTool
+from fastcontext.agent.tool.grep import GrepTool
+
+
+def test_grep_doc_glob_examples_are_valid():
+    """The glob examples in the Grep description must be extension globs, not
+    the malformed dotfile patterns '.js' / '**/.tsx'."""
+    desc = GrepTool().description
+    assert '"*.js"' in desc and '"**/*.tsx"' in desc
+    # The old malformed examples must be gone.
+    assert '(e.g., ".js"' not in desc
+    assert '"**/.tsx"' not in desc
+
+
+def test_documented_extension_glob_actually_matches():
+    """Sanity-check that the documented '*.js' pattern matches by extension
+    (the malformed '.js' would only match a literal dotfile)."""
+    glob = GlobTool()
+    with tempfile.TemporaryDirectory() as cwd:
+        (Path(cwd) / "app.js").write_text("x", encoding="utf-8")
+        (Path(cwd) / "readme.md").write_text("x", encoding="utf-8")
+
+        out = asyncio.run(glob.call(json.dumps({"directory": cwd, "pattern": "*.js"}), cwd=cwd))
+        names = {Path(line).name for line in out.splitlines()}
+        assert names == {"app.js"}