add overwrite command

.github/workflows/_test_release.yml

@@ -7,12 +7,6 @@ on:
         required: true
         type: string
         description: "From which folder this pipeline executes"
-      
-      release-branch:
-        required: false
-        type: string
-        default: "main"
-
 
 env:
   PYTHON_VERSION: "3.10"
@@ -22,7 +16,7 @@ permissions:
 
 jobs:
   build:
-    if: github.ref == 'refs/heads/${{ inputs.release-branch }}'
+    if: github.ref == 'refs/heads/main'
     runs-on: ubuntu-latest
 
     outputs:

.github/workflows/release.yml

@@ -16,7 +16,7 @@ env:
 
 jobs:
   build:
-    if: github.ref == 'refs/heads/0.6'
+    if: github.ref == 'refs/heads/main'
     runs-on: ubuntu-latest
 
     outputs:
@@ -79,10 +79,6 @@ jobs:
           echo short-pkg-name="$SHORT_PKG_NAME" >> $GITHUB_OUTPUT
           echo version="$VERSION" >> $GITHUB_OUTPUT
           echo tag="$TAG" >> $GITHUB_OUTPUT
-          echo "Pkg-name: $PKG_NAME"
-          echo "Short-pkg-name: $SHORT_PKG_NAME"
-          echo "Version: $VERSION"
-          echo "Tag: $TAG"
 
   release-notes:
     needs:
@@ -97,7 +93,7 @@ jobs:
           path: langgraph
           sparse-checkout: | # this only grabs files for relevant dir
             ${{ inputs.working-directory }}
-          ref: "0.6"  #this scopes to just 0.6 branch
+          ref: main # this scopes to just master branch
           fetch-depth: 0 # this fetches entire commit history
       - name: Check Tags
         id: check-tags
@@ -109,48 +105,19 @@ jobs:
           VERSION: ${{ needs.build.outputs.version }}
           TAG: ${{ needs.build.outputs.tag }}
         run: |
-          # 1) Parse major/minor and enforce we're on the 0.6 series
-          MAJOR="${VERSION%%.*}"
-          REST="${VERSION#*.}"
-          MINOR="${REST%%.*}"
-
-          # Minor/major numeric guard: fail if >= 0.7.* (or any non-0 major)
-          if [ -z "$MAJOR" ] || [ -z "$MINOR" ]; then
-            echo "Could not parse VERSION '$VERSION' to MAJOR.MINOR"
-            exit 1
-          fi
-
-          if [ "$MAJOR" -ne 0 ] || [ "$MINOR" -ne 6 ]; then
-            echo "Refusing to release VERSION '$VERSION' from 0.6 maintenance branch (got $MAJOR.$MINOR)"
-            exit 1
-          fi
-
-          # 2) Build a regex that only matches 0.6.* tags, handling both tag shapes
-          #    - Plain:        ^0\.6\.\d+((a|b|rc)\d+)?$
-          #    - With prefix:  ^<SHORT>==0\.6\.\d+((a|b|rc)\d+)?$
-          SERIES_REGEX="0\\.6"
-          if [ -z "$SHORT_PKG_NAME" ]; then
-            REGEX="^${SERIES_REGEX}\\.\\d+((a|b|rc)\\d+)?$"
+          if [ -z $SHORT_PKG_NAME ]; then
+            REGEX="^\\d+\\.\\d+\\.\\d+((a|b|rc)\\d+)?\$"
           else
-            # SHORT_PKG_NAME is already pre-sanitized by your step (e.g., no spaces).
-            REGEX="^${SHORT_PKG_NAME}==${SERIES_REGEX}\\.\\d+((a|b|rc)\\d+)?$"
+            REGEX="^$SHORT_PKG_NAME==\\d+\\.\\d+\\.\\d+((a|b|rc)\\d+)?\$"
           fi
-
-          echo "Tag match regex: $REGEX"
-
-          # 3) Find the most recent tag in this series
-          PREV_TAG="$(git tag --sort=-creatordate | grep -P "$REGEX" | head -1 || true)"
-          echo "Previous tag in series: ${PREV_TAG:-<none>}"
-
-          # 4) If computed TAG equals the previous tag, there’s nothing new to release
-          if [ "$TAG" = "$PREV_TAG" ] && [ -n "$TAG" ]; then
-            echo "No new version to release for 0.6.x (TAG matches previous)."
+          echo $REGEX
+          PREV_TAG=$(git tag --sort=-creatordate | grep -P $REGEX | head -1 || echo "")
+          echo $PREV_TAG
+          if [ "$TAG" == "$PREV_TAG" ]; then
+            echo "No new version to release"
             exit 1
           fi
-
-          # 5) Surface prev-tag for later steps
-          echo "prev-tag=$PREV_TAG" >> "$GITHUB_OUTPUT"
-
+          echo prev-tag="$PREV_TAG" >> $GITHUB_OUTPUT
       - name: Generate release body
         id: generate-release-body
         working-directory: langgraph
@@ -182,7 +149,6 @@ jobs:
     uses: ./.github/workflows/_test_release.yml
     with:
       working-directory: ${{ inputs.working-directory }}
-      release-branch: "0.6"
     secrets: inherit
 
   pre-release-checks:

libs/cli/langgraph_cli/cli.py

@@ -271,7 +271,7 @@ For production use, requires a license key in env var LANGGRAPH_CLOUD_LICENSE_KE
                     f"""Ready!
 - API: http://localhost:{port}
 - Docs: http://localhost:{port}/docs
-- LangSmith Debugger: {debugger_origin}/studio/?baseUrl={debugger_base_url_query}
+- LangGraph Studio: {debugger_origin}/studio/?baseUrl={debugger_base_url_query}
 """
                 )
                 sys.stdout.flush()
@@ -652,17 +652,11 @@ def dockerfile(
     help="Wait for a debugger client to connect to the debug port before starting the server",
     default=False,
 )
-@click.option(
-    "--debugger-url",
-    type=str,
-    default=None,
-    help="URL of the LangSmith Debugger instance to connect to. Defaults to https://smith.langchain.com",
-)
 @click.option(
     "--studio-url",
     type=str,
     default=None,
-    help="(Deprecated: use --debugger-url instead) URL of the LangSmith Debugger instance to connect to.",
+    help="URL of the LangGraph Studio instance to connect to. Defaults to https://smith.langchain.com",
 )
 @click.option(
     "--allow-blocking",
@@ -698,21 +692,12 @@ def dev(
     no_browser: bool,
     debug_port: Optional[int],
     wait_for_client: bool,
-    debugger_url: Optional[str],
     studio_url: Optional[str],
     allow_blocking: bool,
     tunnel: bool,
     server_log_level: str,
 ):
     """CLI entrypoint for running the LangGraph API server."""
-    if studio_url is not None:
-        click.secho(
-            "Warning: --studio-url is deprecated and will be removed in a future version. "
-            "Please use --debugger-url instead.",
-            fg="yellow",
-        )
-        if debugger_url is None:
-            debugger_url = studio_url
     try:
         from langgraph_api.cli import run_server  # type: ignore
     except ImportError:
@@ -776,7 +761,7 @@ def dev(
         http=config_json.get("http"),
         ui=config_json.get("ui"),
         ui_config=config_json.get("ui_config"),
-        studio_url=debugger_url,
+        studio_url=studio_url,
         allow_blocking=allow_blocking,
         tunnel=tunnel,
         server_level=server_log_level,

libs/langgraph/langgraph/pregel/__init__.py

@@ -1,3 +1,4 @@
+from langgraph.pregel._write import Overwrite, overwrite
 from langgraph.pregel.main import NodeBuilder, Pregel
 
-__all__ = ("Pregel", "NodeBuilder")
+__all__ = ("Pregel", "NodeBuilder", "overwrite", "Overwrite")

libs/langgraph/langgraph/pregel/_algo.py

@@ -71,6 +71,7 @@ from langgraph.pregel._call import get_runnable_for_task, identifier
 from langgraph.pregel._io import read_channels
 from langgraph.pregel._log import logger
 from langgraph.pregel._read import INPUT_CACHE_KEY_TYPE, PregelNode
+from langgraph.pregel._write import _Overwrite
 from langgraph.runtime import DEFAULT_RUNTIME, Runtime
 from langgraph.types import (
     All,
@@ -198,8 +199,16 @@ def local_read(
         # apply writes
         local_channels: dict[str, BaseChannel] = {}
         for k in channels:
-            cc = channels[k].copy()
-            cc.update(updated[k])
+            if updated[k]:
+                # If any overwrite is present for this channel, reflect it directly
+                ow = next((v for v in updated[k] if isinstance(v, _Overwrite)), None)
+                if ow is not None:
+                    cc = channels[k].from_checkpoint(ow.value)
+                else:
+                    cc = channels[k].copy()
+                    cc.update(updated[k])
+            else:
+                cc = channels[k].copy()
             local_channels[k] = cc
         # read fresh values
         values = read_channels(local_channels, select)
@@ -277,12 +286,16 @@ def apply_writes(
 
     # Group writes by channel
     pending_writes_by_channel: dict[str, list[Any]] = defaultdict(list)
+    overwrite_by_channel: dict[str, Any] = {}
     for task in tasks:
         for chan, val in task.writes:
             if chan in (NO_WRITES, PUSH, RESUME, INTERRUPT, RETURN, ERROR):
-                pass
-            elif chan in channels:
-                pending_writes_by_channel[chan].append(val)
+                continue
+            if chan in channels:
+                if isinstance(val, _Overwrite):
+                    overwrite_by_channel[chan] = val.value
+                else:
+                    pending_writes_by_channel[chan].append(val)
             else:
                 logger.warning(
                     f"Task {task.name} with path {task.path} wrote to unknown channel {chan}, ignoring it."
@@ -290,13 +303,26 @@ def apply_writes(
 
     # Apply writes to channels
     updated_channels: set[str] = set()
-    for chan, vals in pending_writes_by_channel.items():
+    for chan in set(pending_writes_by_channel.keys()) | set(
+        overwrite_by_channel.keys()
+    ):
         if chan in channels:
-            if channels[chan].update(vals) and next_version is not None:
-                checkpoint["channel_versions"][chan] = next_version
-                # unavailable channels can't trigger tasks, so don't add them
+            if chan in overwrite_by_channel:
+                # Overwrite the entire channel value, bypassing reducers.
+                channels[chan] = channels[chan].from_checkpoint(
+                    overwrite_by_channel[chan]
+                )
+                if next_version is not None:
+                    checkpoint["channel_versions"][chan] = next_version
                 if channels[chan].is_available():
                     updated_channels.add(chan)
+            else:
+                vals = pending_writes_by_channel.get(chan, [])
+                if channels[chan].update(vals) and next_version is not None:
+                    checkpoint["channel_versions"][chan] = next_version
+                    # unavailable channels can't trigger tasks, so don't add them
+                    if channels[chan].is_available():
+                        updated_channels.add(chan)
 
     # Channels that weren't updated in this step are notified of a new step
     if bump_step:

libs/langgraph/langgraph/pregel/_write.py

@@ -26,6 +26,32 @@ SKIP_WRITE = object()
 PASSTHROUGH = object()
 
 
+class _Overwrite:
+    """Marker wrapper indicating a direct channel overwrite.
+
+    Use via `overwrite(channel, value)` or `Overwrite(value)`.
+    """
+
+    __slots__ = ("value",)
+
+    def __init__(self, value: Any):
+        self.value = value
+
+
+def Overwrite(value: Any) -> _Overwrite:
+    """Wrap a value to force overwrite a channel, bypassing reducers."""
+    return _Overwrite(value)
+
+
+def overwrite(channel: str, value: Any) -> ChannelWriteEntry:
+    """Convenience factory for a write that overwrites the target channel.
+
+    Example:
+        NodeBuilder().write_to(overwrite("foo", 123))
+    """
+    return ChannelWriteEntry(channel, Overwrite(value))
+
+
 class ChannelWriteEntry(NamedTuple):
     channel: str
     """Channel name to write to."""

libs/langgraph/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "langgraph"
-version = "0.6.11"
+version = "0.6.10"
 description = "Building stateful, multi-actor applications with LLMs"
 authors = []
 requires-python = ">=3.9"
@@ -13,7 +13,7 @@ license = "MIT"
 license-files = ['LICENSE']
 dependencies = [
     "langchain-core>=0.1",
-    "langgraph-checkpoint>=2.1.0,<4.0.0",
+    "langgraph-checkpoint>=2.1.0,<3.0.0",
     "langgraph-sdk>=0.2.2,<0.3.0",
     "langgraph-prebuilt>=0.6.0,<0.7.0",
     "xxhash>=3.5.0",

libs/langgraph/uv.lock

@@ -1428,7 +1428,7 @@ wheels = [
 
 [[package]]
 name = "langgraph"
-version = "0.6.11"
+version = "0.6.10"
 source = { editable = "." }
 dependencies = [
     { name = "langchain-core" },
@@ -1674,7 +1674,7 @@ dev = [
 
 [[package]]
 name = "langgraph-prebuilt"
-version = "0.6.5"
+version = "0.6.4"
 source = { editable = "../prebuilt" }
 dependencies = [
     { name = "langchain-core" },

libs/prebuilt/pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "langgraph-prebuilt"
-version = "0.6.5"
+version = "0.6.4"
 description = "Library with high-level APIs for creating and executing LangGraph agents and tools."
 authors = []
 requires-python = ">=3.9"
@@ -12,7 +12,7 @@ readme = "README.md"
 license = "MIT"
 license-files = ['LICENSE']
 dependencies = [
-    "langgraph-checkpoint>=2.1.0,<4.0.0",
+    "langgraph-checkpoint>=2.1.0,<3.0.0",
     "langchain-core>=0.3.67",
 ]
 

libs/prebuilt/uv.lock

@@ -257,7 +257,7 @@ wheels = [
 
 [[package]]
 name = "langgraph"
-version = "0.6.11"
+version = "0.6.10"
 source = { editable = "../langgraph" }
 dependencies = [
     { name = "langchain-core" },
@@ -403,7 +403,7 @@ dev = [
 
 [[package]]
 name = "langgraph-prebuilt"
-version = "0.6.5"
+version = "0.6.4"
 source = { editable = "." }
 dependencies = [
     { name = "langchain-core" },