diff --git a/clients/terminal/tui/renderers/filesystem.py b/clients/terminal/tui/renderers/filesystem.py
index 293c43c..24f83bf 100644
--- a/clients/terminal/tui/renderers/filesystem.py
+++ b/clients/terminal/tui/renderers/filesystem.py
@@ -60,7 +60,7 @@
         args = msg.get("args") or {}
         action = args.get("action")
 
-        body = self._render_body(text, action, args, success, theme)
+        body = self._render_body(text, action, args, success, theme, msg.get("metadata") or {})
         color = theme.tool_success if success else theme.tool_error
         panel = Panel(
             body,
@@ -76,12 +76,20 @@
     # ── dispatch ───────────────────────────────────────────────────────────
 
     def _render_body(
-        self, text: str, action: str | None, args: dict, success: bool, theme: Theme
+        self,
+        text: str,
+        action: str | None,
+        args: dict,
+        success: bool,
+        theme: Theme,
+        metadata: dict | None = None,
     ) -> RenderableType:
         if not success:
             # Errors carry a human-readable message; do not attempt to parse.
             return Text(text, style=theme.tool_error.hex)
 
+        if action == "edit":
+            return self._render_edit(text, metadata or {}, theme)
         if action in _DIFF_ACTIONS:
             return self._render_diff(text, action, theme)
         if action == "list":
@@ -119,6 +127,20 @@
             highlight_unified_diff(diff, theme),
         )
 
+    def _render_edit(self, text: str, metadata: dict, theme: Theme) -> RenderableType:
+        # ``edit`` keeps its model-facing output short (a one-line summary); the
+        # unified diff is carried in ``metadata["diff"]`` purely for display, so
+        # the model's context is unchanged. Render the summary dim, then the
+        # highlighted diff; fall back to plain when no diff is present.
+        diff = metadata.get("diff") if metadata else None
+        if not diff:
+            return Text(text, style=theme.text_dim.hex)
+        return Group(
+            Text(text, style=theme.text_dim.hex),
+            Text(""),
+            highlight_unified_diff(diff, theme),
+        )
+
     # ── read ───────────────────────────────────────────────────────────────
 
     def _render_read(self, text: str, args: dict, theme: Theme) -> RenderableType:
diff --git a/navi/tools/filesystem.py b/navi/tools/filesystem.py
index 576d24f..3e92178 100644
--- a/navi/tools/filesystem.py
+++ b/navi/tools/filesystem.py
@@ -616,12 +616,18 @@
         new_text = text.replace(old, new, 1)
         path.write_text(new_text, encoding="utf-8")
         delta = len(new_text.encode()) - len(text.encode())
+        summary = (
+            f"Edited {path}: replaced {len(old.encode())} B with "
+            f"{len(new.encode())} B (delta {delta:+d} B)."
+        )
+        # Keep the model-facing output short; carry the unified diff in metadata
+        # for the TUI to render with red/green highlighting (the model does not
+        # see metadata, so its context stays unchanged).
+        diff = _unified_diff(text.splitlines(), new_text.splitlines(), path)
         return ToolResult(
             success=True,
-            output=(
-                f"Edited {path}: replaced {len(old.encode())} B with "
-                f"{len(new.encode())} B (delta {delta:+d} B)."
-            ),
+            output=summary,
+            metadata={"diff": diff} if diff else {},
         )
 
     def _edit_lines(self, path: Path, params: dict) -> ToolResult:
diff --git a/tests/clients/test_filesystem_renderer.py b/tests/clients/test_filesystem_renderer.py
index aee354c..122c63f 100644
--- a/tests/clients/test_filesystem_renderer.py
+++ b/tests/clients/test_filesystem_renderer.py
@@ -148,6 +148,49 @@
     assert body.plain.startswith("Applied 1 operation(s)")
 
 
+def test_edit_renders_diff_from_metadata() -> None:
+    set_active_theme("gnexus-dark")
+    theme = get_active_theme()
+    renderer = FilesystemToolResultRenderer()
+    msg = {
+        "type": "tool_call",
+        "tool": "filesystem",
+        "args": {"action": "edit"},
+        "result": "Edited a.py: replaced 5 B with 5 B (delta +0 B).",
+        "success": True,
+        "metadata": {
+            "diff": "--- a.py\n+++ b.py\n@@ -1,3 +1,3 @@\n alpha\n-beta\n+BETA\n gamma\n"
+        },
+    }
+    body = _body(renderer.render(msg))
+    # Group(summary, blank, diff)
+    renderables = body.renderables
+    summary = renderables[0]
+    diff = renderables[2]
+    assert isinstance(summary, Text)
+    assert "Edited a.py" in summary.plain
+    assert _span_styles_at(summary, "Edited a.py") == {theme.text_dim.hex}
+    assert isinstance(diff, Text)
+    assert _span_styles_at(diff, "+BETA") == {theme.success.hex}
+    assert _span_styles_at(diff, "-beta") == {theme.error.hex}
+
+
+def test_edit_without_metadata_falls_back_to_plain() -> None:
+    set_active_theme("gnexus-dark")
+    theme = get_active_theme()
+    renderer = FilesystemToolResultRenderer()
+    msg = {
+        "type": "tool_call",
+        "tool": "filesystem",
+        "args": {"action": "edit"},
+        "result": "Edited a.py: replaced 5 B with 5 B (delta +0 B).",
+        "success": True,
+    }
+    body = _body(renderer.render(msg))
+    assert isinstance(body, Text)
+    assert _span_styles_at(body, "Edited a.py") == {theme.text_dim.hex}
+
+
 def test_diff_error_renders_plain_error_color() -> None:
     set_active_theme("gnexus-dark")
     theme = get_active_theme()
diff --git a/tests/unit/tools/test_filesystem.py b/tests/unit/tools/test_filesystem.py
index e8dde50..2b4fb96 100644
--- a/tests/unit/tools/test_filesystem.py
+++ b/tests/unit/tools/test_filesystem.py
@@ -131,6 +131,12 @@
 
         assert result.success
         assert f.read_text() == "alpha\nBETA\ngamma\n"
+        # Model-facing output stays short; the unified diff rides in metadata for
+        # the TUI so the model's context is unchanged.
+        assert "replaced" in result.output
+        assert "@@" not in result.output
+        assert "-beta" in result.metadata["diff"]
+        assert "+BETA" in result.metadata["diff"]
 
     async def test_edit_requires_old_text(self, tool, tmp_path):
         f = tmp_path / "edit.txt"