diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1467829..296d413 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,18 @@
 # Changelog
 
+## 0.4.0
+
+### Features
+
+- Added `Document.insert()` and `Editor.insert()` for inserting an item at a specific position in a sequence. Uses Python `list.insert()` semantics (negative indices count from end, out-of-range clamps).
+- Added `Document.get()` and `Editor.get()` for non-raising value access. This returns a default (defaults to `None`) when the path doesn't exist, similar to `dict.get()`.
+- Added `Document.sync()` and `Editor.sync()` that diffs the current value at a path against a desired value and applies the minimal set of patches. Supports recursive mapping diffing and `SequenceMatcher`-based list diffing to preserve comments and formatting on unchanged elements.
+
+### Internal
+
+- Introduced `OpInner` enum in Rust to support local ops (like `insert_at`) alongside yamlpatch-delegated operations.
+- Extracted `KeyPart` type alias to `_types.py`.
+
 ## 0.3.0
 
 ### Features
diff --git a/Cargo.lock b/Cargo.lock
index c3d3e8d..ea6dd03 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -466,7 +466,7 @@ dependencies = [
 
 [[package]]
 name = "yamltrip"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "indexmap",
  "pyo3",
diff --git a/Cargo.toml b/Cargo.toml
index 35e0616..6745ae5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "yamltrip"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2024"
 license = "MIT"
 
diff --git a/README.md b/README.md
index 4e506f5..43b5804 100644
--- a/README.md
+++ b/README.md
@@ -65,6 +65,9 @@ doc["items"]                  # ["a", "b"]
 doc["items", 0]               # "a"
 ("items", 0) in doc           # True
 
+doc.get("items", 0)               # "a" (returns None if missing)
+doc.get("missing", default=42)    # 42
+
 doc.replace("items", 0, value="x")
 doc.replace("items", value=["x", "y"])  # dicts and lists accepted
 doc.add("items", key="c", value=3)
@@ -73,8 +76,10 @@ doc.upsert("config", value={"debug": True})  # dicts and lists accepted
 doc.remove("items", 0)
 doc.prune_remove("a", "b", "c")  # remove + prune empty parents
 doc.append("items", value="c")
+doc.insert("items", index=1, value="between")  # positional insert
 doc.extend_list("items", values=["d", "e"])
 doc.remove_from_list("items", values=["a"])
+doc.sync("items", value=["a", "new", "b"])  # minimal diff-and-patch
 
 doc.query("items")            # Feature with location info
 doc.query_pretty("items")    # Feature with surrounding context
@@ -94,7 +99,9 @@ with yamltrip.edit("config.yml") as ed:
     ed.replace("version", value="2.0")
     ed.upsert("new_key", value="new_value")
     ed.remove("old_key")
+    ed.sync("deps", value={"a": "1.0", "b": "2.0"})  # minimal patching
     print(ed["version"])        # "2.0"
+    print(ed.get("missing"))    # None
     print(ed.original["version"])  # original value before edits
 ```
 
@@ -131,8 +138,9 @@ All yamltrip errors inherit from `YAMLTripError`:
 - **Integer keys cannot create structures.** `upsert()` with integer path
   components can update existing sequence entries but cannot create new
   intermediate mappings. Only string keys create new mappings.
-- **No negative sequence indices.** Python-style negative indexing is not
-  supported.
+- **No negative sequence indices for lookup.** Python-style negative indexing
+  is not supported for `[]` access or `replace()`/`remove()`. However,
+  `insert()` accepts negative indices (matching `list.insert()` semantics).
 - **Line endings preserved as-is.** No CRLF/LF normalization. Mixed line
   endings pass through unchanged.
 
diff --git a/pyproject.toml b/pyproject.toml
index c6476ed..28cf098 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ requires = [ "maturin>=1.0,<2.0" ]
 
 [project]
 name = "yamltrip"
-version = "0.3.0"
+version = "0.4.0"
 description = "A round-tripping YAML library for Python"
 readme = "README.md"
 authors = [ { name = "Nathan McDougall", email = "nathan.j.mcdougall@gmail.com" } ]