diff --git a/packages/coding-agent/skills/edit/.gitignore b/packages/coding-agent/skills/edit/.gitignore
new file mode 100644
index 000000000..560798033
--- /dev/null
+++ b/packages/coding-agent/skills/edit/.gitignore
@@ -0,0 +1,4 @@
+__pycache__/
+*.pyc
+.venv/
+uv.lock
diff --git a/packages/coding-agent/skills/edit/SKILL.md b/packages/coding-agent/skills/edit/SKILL.md
new file mode 100644
index 000000000..bb7d1ee89
--- /dev/null
+++ b/packages/coding-agent/skills/edit/SKILL.md
@@ -0,0 +1,22 @@
+---
+name: edit
+description: Replace an exact, unique string in an existing file. Use for targeted single-occurrence edits to files from the IPython kernel instead of rewriting the whole file.
+---
+
+# Edit
+
+Make a targeted edit to an existing file by replacing one exact, unique
+occurrence of a string. `old_str` must appear exactly once in the file.
+
+Call directly from the kernel:
+
+    await edit(path="pkg/file.py", old_str=old, new_str=new)
+
+Use exact old/new strings. If the text contains triple double quotes, use
+triple single-quoted variables (`old = '''...'''`) or build `old`/`new` from
+inspected file slices. Returns a short confirmation; raises if `old_str` is
+missing or matches more than once (widen the snippet to make it unique).
+
+Or from a shell cell:
+
+    !edit --path pkg/file.py --old-str "..." --new-str "..."
diff --git a/packages/coding-agent/skills/edit/pyproject.toml b/packages/coding-agent/skills/edit/pyproject.toml
new file mode 100644
index 000000000..151216540
--- /dev/null
+++ b/packages/coding-agent/skills/edit/pyproject.toml
@@ -0,0 +1,15 @@
+[project]
+name = "edit"
+version = "0.1.0"
+requires-python = ">=3.10"
+dependencies = []
+
+[project.scripts]
+edit = "rlm.skill:cli"
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/edit"]
diff --git a/packages/coding-agent/skills/edit/src/edit/__init__.py b/packages/coding-agent/skills/edit/src/edit/__init__.py
new file mode 100644
index 000000000..63f8eae34
--- /dev/null
+++ b/packages/coding-agent/skills/edit/src/edit/__init__.py
@@ -0,0 +1,41 @@
+"""Exact single-occurrence string replacement for existing files."""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+
+async def run(path: str, old_str: str, new_str: str) -> str:
+    """Replace a unique string in a file.
+
+    ``old_str`` must appear exactly once in the file at ``path``; that match is
+    replaced with ``new_str`` and the file is written back in place. Prefer this
+    over rewriting a whole file for targeted edits.
+
+    Args:
+        path: File to edit, relative to the working directory, absolute, or
+            `~`-prefixed (the leading `~`/`~user` is expanded to the home dir).
+        old_str: Exact text to find. Must occur exactly once in the file.
+        new_str: Replacement text.
+
+    Returns:
+        A short confirmation message.
+
+    Raises:
+        FileNotFoundError: If ``path`` does not exist.
+        ValueError: If ``old_str`` is absent or matches more than once.
+    """
+    filepath = Path(path).expanduser()
+    if not filepath.exists():
+        raise FileNotFoundError(f"{path} not found")
+    content = filepath.read_text(encoding="utf-8")
+    count = content.count(old_str)
+    if count == 0:
+        raise ValueError(f"string not found in {path}")
+    if count > 1:
+        raise ValueError(
+            f"found {count} occurrences in {path}, need exactly 1 — "
+            "widen the snippet to make it unique"
+        )
+    filepath.write_text(content.replace(old_str, new_str, 1), encoding="utf-8")
+    return f"Edited {path}"
diff --git a/packages/coding-agent/test/builtin-skills.test.ts b/packages/coding-agent/test/builtin-skills.test.ts
index 35072059e..ec2a023f5 100644
--- a/packages/coding-agent/test/builtin-skills.test.ts
+++ b/packages/coding-agent/test/builtin-skills.test.ts
@@ -163,6 +163,15 @@ describe("builtin skills", () => {
 			expect(skills.map((s) => s.name)).toContain("skill-creator");
 		});
 
+		it("ships the edit skill as a python skill importable as `edit`", () => {
+			const { skills } = loadSkillsFromDir({ dir: getBundledSkillsDir(), source: "builtin" });
+
+			const edit = skills.find((s) => s.name === "edit");
+			expect(edit).toBeDefined();
+			expect(edit?.kind).toBe("python");
+			expect(edit?.kind === "python" && edit.python.importName).toBe("edit");
+		});
+
 		it("loads the skill-creator python template as a valid python skill", () => {
 			const referencePath = join(getBundledSkillsDir(), "skill-creator", "references", "python-skills.md");
 			const reference = readFileSync(referencePath, "utf-8");