diff --git a/src/plyngent/tools/file/__init__.py b/src/plyngent/tools/file/__init__.py
new file mode 100644
index 0000000..ee36c14
--- /dev/null
+++ b/src/plyngent/tools/file/__init__.py
@@ -0,0 +1,6 @@
+from .edit_replace import edit_replace as edit_replace
+from .listdir import listdir as listdir
+from .read import read_file as read_file
+from .write import write_file as write_file
+
+FILE_TOOLS = [read_file, write_file, listdir, edit_replace]
diff --git a/src/plyngent/tools/file/edit_replace.py b/src/plyngent/tools/file/edit_replace.py
new file mode 100644
index 0000000..c7e8d31
--- /dev/null
+++ b/src/plyngent/tools/file/edit_replace.py
@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+from plyngent.agent import tool
+from plyngent.tools.workspace import resolve_path
+
+
+@tool
+def edit_replace(path: str, old_string: str, new_string: str) -> str:
+    """Replace the first occurrence of ``old_string`` with ``new_string`` in a file."""
+    if not old_string:
+        return "error: old_string must not be empty"
+    target = resolve_path(path)
+    if not target.is_file():
+        return f"error: not a file: {path}"
+    text = target.read_text(encoding="utf-8", errors="replace")
+    if old_string not in text:
+        return "error: old_string not found in file"
+    updated = text.replace(old_string, new_string, 1)
+    _ = target.write_text(updated, encoding="utf-8")
+    return f"replaced first occurrence in {path}"
diff --git a/src/plyngent/tools/file/listdir.py b/src/plyngent/tools/file/listdir.py
new file mode 100644
index 0000000..b46877d
--- /dev/null
+++ b/src/plyngent/tools/file/listdir.py
@@ -0,0 +1,17 @@
+from __future__ import annotations
+
+from plyngent.agent import tool
+from plyngent.tools.workspace import resolve_path
+
+
+@tool
+def listdir(path: str = ".") -> str:
+    """List entries in a directory under the workspace (name and type)."""
+    target = resolve_path(path)
+    if not target.is_dir():
+        return f"error: not a directory: {path}"
+    lines: list[str] = []
+    for entry in sorted(target.iterdir(), key=lambda p: p.name):
+        kind = "dir" if entry.is_dir() else "file"
+        lines.append(f"{kind}\t{entry.name}")
+    return "\n".join(lines) if lines else "(empty)"
diff --git a/src/plyngent/tools/file/read.py b/src/plyngent/tools/file/read.py
new file mode 100644
index 0000000..d7b16c5
--- /dev/null
+++ b/src/plyngent/tools/file/read.py
@@ -0,0 +1,24 @@
+from __future__ import annotations
+
+from plyngent.agent import tool
+from plyngent.tools.workspace import resolve_path
+
+
+@tool
+def read_file(path: str, *, offset: int = 0, limit: int | None = None) -> str:
+    """Read a text file under the workspace.
+
+    ``offset`` is 0-based line start; ``limit`` is max lines (None = rest of file).
+    """
+    target = resolve_path(path)
+    if not target.is_file():
+        return f"error: not a file: {path}"
+    text = target.read_text(encoding="utf-8", errors="replace")
+    lines = text.splitlines(keepends=True)
+    if offset < 0:
+        return "error: offset must be >= 0"
+    start = offset
+    end = len(lines) if limit is None else min(len(lines), start + limit)
+    if start >= len(lines):
+        return ""
+    return "".join(lines[start:end])
diff --git a/src/plyngent/tools/file/write.py b/src/plyngent/tools/file/write.py
new file mode 100644
index 0000000..8a1aff1
--- /dev/null
+++ b/src/plyngent/tools/file/write.py
@@ -0,0 +1,13 @@
+from __future__ import annotations
+
+from plyngent.agent import tool
+from plyngent.tools.workspace import resolve_path
+
+
+@tool
+def write_file(path: str, content: str) -> str:
+    """Write text content to a file under the workspace (creates parents)."""
+    target = resolve_path(path)
+    target.parent.mkdir(parents=True, exist_ok=True)
+    _ = target.write_text(content, encoding="utf-8")
+    return f"wrote {len(content)} characters to {path}"