**Description:** Right now, we interrupt even if the provided ToolConfig
has all false values. We should ignore ToolConfigs which do not have at
least one value marked as true (just as we would if tool_name: False was
passed into the dict).
# Main Changes
1. Adding decorator utilities for dynamically defining middleware with
single hook functions (see an example below for dynamic system prompt)
2. Adding better conditional edge drawing with jump configuration
attached to middleware. Can be registered w/ the decorator new
decorator!
## Decorator Utilities
```py
from langchain.agents.middleware_agent import create_agent, AgentState, ModelRequest
from langchain.agents.middleware.types import modify_model_request
from langchain_core.messages import HumanMessage
from langgraph.checkpoint.memory import InMemorySaver
@modify_model_request
def modify_system_prompt(request: ModelRequest, state: AgentState) -> ModelRequest:
request.system_prompt = (
"You are a helpful assistant."
f"Please record the number of previous messages in your response: {len(state['messages'])}"
)
return request
agent = create_agent(
model="openai:gpt-4o-mini",
middleware=[modify_system_prompt]
).compile(checkpointer=InMemorySaver())
```
## Visualization and Routing improvements
We now require that middlewares define the valid jumps for each hook.
If using the new decorator syntax, this can be done with:
```py
@before_model(jump_to=["__end__"])
@after_model(jump_to=["tools", "__end__"])
```
If using the subclassing syntax, you can use these two class vars:
```py
class MyMiddlewareAgentMiddleware):
before_model_jump_to = ["__end__"]
after_model_jump_to = ["tools", "__end__"]
```
Open for debate if we want to bundle these in a single jump map / config
for a middleware. Easy to migrate later if we decide to add more hooks.
We will need to **really clearly document** that these must be
explicitly set in order to enable conditional edges.
Notice for the below case, `Middleware2` does actually enable jumps.
<table>
<thead>
<tr>
<th>Before (broken), adding conditional edges unconditionally</th>
<th>After (fixed), adding conditional edges sparingly</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<img width="619" height="508" alt="Screenshot 2025-09-23 at 10 23 23 AM"
src="https://github.com/user-attachments/assets/bba2d098-a839-4335-8e8c-b50dd8090959"
/>
</td>
<td>
<img width="469" height="490" alt="Screenshot 2025-09-23 at 10 23 13 AM"
src="https://github.com/user-attachments/assets/717abf0b-fc73-4d5f-9313-b81247d8fe26"
/>
</td>
</tr>
</tbody>
</table>
<details>
<summary>Snippet for the above</summary>
```py
from typing import Any
from langchain.agents.tool_node import InjectedState
from langgraph.runtime import Runtime
from langchain.agents.middleware.types import AgentMiddleware, AgentState
from langchain.agents.middleware_agent import create_agent
from langchain_core.tools import tool
from typing import Annotated
from langchain_core.messages import HumanMessage
from typing_extensions import NotRequired
@tool
def simple_tool(input: str) -> str:
"""A simple tool."""
return "successful tool call"
class Middleware1(AgentMiddleware):
"""Custom middleware that adds a simple tool."""
tools = [simple_tool]
def before_model(self, state: AgentState, runtime: Runtime) -> None:
return None
def after_model(self, state: AgentState, runtime: Runtime) -> None:
return None
class Middleware2(AgentMiddleware):
before_model_jump_to = ["tools", "__end__"]
def before_model(self, state: AgentState, runtime: Runtime) -> None:
return None
def after_model(self, state: AgentState, runtime: Runtime) -> None:
return None
class Middleware3(AgentMiddleware):
def before_model(self, state: AgentState, runtime: Runtime) -> None:
return None
def after_model(self, state: AgentState, runtime: Runtime) -> None:
return None
builder = create_agent(
model="openai:gpt-4o-mini",
middleware=[Middleware1(), Middleware2(), Middleware3()],
system_prompt="You are a helpful assistant.",
)
agent = builder.compile()
```
</details>
## More Examples
### Guardrails `after_model`
<img width="379" height="335" alt="Screenshot 2025-09-23 at 10 40 09 AM"
src="https://github.com/user-attachments/assets/45bac7dd-398e-45d1-ae58-6ecfa27dfc87"
/>
<details>
<summary>Code</summary>
```py
from langchain.agents.middleware_agent import create_agent, AgentState, ModelRequest
from langchain.agents.middleware.types import after_model
from langchain_core.messages import HumanMessage, AIMessage
from langgraph.checkpoint.memory import InMemorySaver
from typing import cast, Any
@after_model(jump_to=["model", "__end__"])
def after_model_hook(state: AgentState) -> dict[str, Any]:
"""Check the last AI message for safety violations."""
last_message_content = cast(AIMessage, state["messages"][-1]).content.lower()
print(last_message_content)
unsafe_keywords = ["pineapple"]
if any(keyword in last_message_content for keyword in unsafe_keywords):
# Jump back to model to regenerate response
return {"jump_to": "model", "messages": [HumanMessage("Please regenerate your response, and don't talk about pineapples. You can talk about apples instead.")]}
return {"jump_to": "__end__"}
# Create agent with guardrails middleware
agent = create_agent(
model="openai:gpt-4o-mini",
middleware=[after_model_hook],
system_prompt="Keep your responses to one sentence please!"
).compile()
# Test with potentially unsafe input
result = agent.invoke(
{"messages": [HumanMessage("Tell me something about pineapples")]},
)
for msg in result["messages"]:
print(msg.pretty_print())
"""
================================ Human Message =================================
Tell me something about pineapples
None
================================== Ai Message ==================================
Pineapples are tropical fruits known for their sweet, tangy flavor and distinctive spiky exterior.
None
================================ Human Message =================================
Please regenerate your response, and don't talk about pineapples. You can talk about apples instead.
None
================================== Ai Message ==================================
Apples are popular fruits that come in various varieties, known for their crisp texture and sweetness, and are often used in cooking and baking.
None
"""
```
</details>
- Removes Codespell from deps, docs, and `Makefile`s
- Python version requirements in all `pyproject.toml` files now use the
`~=` (compatible release) specifier
- All dependency groups and main dependencies now use explicit lower and
upper bounds, reducing potential for breaking changes
We want state schema as the input schema to middleware nodes because the
conditional edges after these nodes need access to the full state.
Also, we just generally want all state passed to middleware nodes, so we
should be specifying this explicitly. If we don't, the state annotations
used by users in their node signatures are used (so they might be
missing fields).
# Changes
## Adds support for `DynamicSystemPromptMiddleware`
```py
from langchain.agents.middleware import DynamicSystemPromptMiddleware
from langgraph.runtime import Runtime
from typing_extensions import TypedDict
class Context(TypedDict):
user_name: str
def system_prompt(state: AgentState, runtime: Runtime[Context]) -> str:
user_name = runtime.context.get("user_name", "n/a")
return f"You are a helpful assistant. Always address the user by their name: {user_name}"
middleware = DynamicSystemPromptMiddleware(system_prompt)
```
## Adds support for `runtime` in middleware hooks
```py
class AgentMiddleware(Generic[StateT, ContextT]):
def modify_model_request(
self,
request: ModelRequest,
state: StateT,
runtime: Runtime[ContextT], # Optional runtime parameter
) -> ModelRequest:
# upgrade model if runtime.context.subscription is `top-tier` or whatever
```
## Adds support for omitting state attributes from input / output
schemas
```py
from typing import Annotated, NotRequired
from langchain.agents.middleware.types import PrivateStateAttr, OmitFromInput, OmitFromOutput
class CustomState(AgentState):
# Private field - not in input or output schemas
internal_counter: NotRequired[Annotated[int, PrivateStateAttr]]
# Input-only field - not in output schema
user_input: NotRequired[Annotated[str, OmitFromOutput]]
# Output-only field - not in input schema
computed_result: NotRequired[Annotated[str, OmitFromInput]]
```
## Additionally
* Removes filtering of state before passing into middleware hooks
Typing is not foolproof here, still need to figure out some of the
generics stuff w/ state and context schema extensions for middleware.
TODO:
* More docs for middleware, should hold off on this until other prios
like MCP and deepagents are met
---------
Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>
## Summary
This PR fixes several bugs and improves the example code in
`BaseChatMessageHistory` docstring that would prevent it from working
correctly.
### Bugs Fixed
- **Critical bug**: Fixed `json.dump(messages, f)` →
`json.dump(serialized, f)` - was using wrong variable
- **NameError**: Fixed bare variable references to use
`self.storage_path` and `self.session_id`
- **Missing imports**: Added required imports (`json`, `os`, message
converters) to make example runnable
### Improvements
- Added missing type hints following project standards (`messages() ->
list[BaseMessage]`, `clear() -> None`)
- Added robust error handling with `FileNotFoundError` exception
handling
- Added directory creation with `os.makedirs(exist_ok=True)` to prevent
path errors
- Improved performance: `json.load(f)` instead of `json.loads(f.read())`
- Added explicit UTF-8 encoding to all file operations
- Updated stores.py to use modern union syntax (`int | None` vs
`Optional[int]`)
### Test Plan
- [x] Code passes linting (`ruff check`)
- [x] Example code now has all required imports and proper syntax
- [x] Fixed variable references prevent runtime errors
- [x] Follows project's type annotation standards
The example code in the docstring is now fully functional and follows
LangChain's coding standards.
---------
Co-authored-by: sadiqkhzn <sadiqkhzn@users.noreply.github.com>
# Main changes / new features
## Better support for parallel tool calls
1. Support for multiple tool calls requiring human input
2. Support for combination of tool calls requiring human input + those
that are auto-approved
3. Support structured output w/ tool calls requiring human input
4. Support structured output w/ standard tool calls
## Shortcut for allowed actions
Adds a shortcut where tool config can be specified as a `bool`, meaning
"all actions allowed"
```py
HumanInTheLoopMiddleware(tool_configs={"expensive_tool": True})
```
## A few design decisions here
* We only raise one interrupt w/ all `HumanInterrupt`s, currently we
won't be able to execute all tools until all of these are resolved. This
isn't super blocking bc we can't re-invoke the model until all tools
have finished execution. That being said, if you have a long running
auto-approved tool, this could slow things down.
## TODOs
* Ideally, we would rename `accept` -> `approve`
* Ideally, we would rename `respond` -> `reject`
* Docs update (@sydney-runkle to own)
* In another PR I'd like to refactor testing to have one file for each
prebuilt middleware :)
Fast follow to https://github.com/langchain-ai/langchain/pull/32962
which was deemed as too breaking
Adds documentation for the integration langchain-scraperapi, which
contains 3 tools using the ScraperAPI service.
The tools give AI agents the ability to
Scrape the web and return HTML/text/markdown
Perform Google search and return json output
Perform Amazon search and return json output
For reference, here is the official repo for langchain_scraperapi:
https://github.com/scraperapi/langchain-scraperapi
Description:
Add a docstring to _load_map_reduce_chain in chains/summarize/ to
explain the purpose of the prompt argument and document function
parameters. This addresses an existing TODO in the codebase.
Issue:
N/A (documentation improvement only)
Dependencies:
None
**Description:**
Add a docstring to `_load_stuff_chain` in `chains/summarize/` to explain
the purpose of the `prompt` argument and document function parameters.
This addresses an existing TODO in the codebase.
**Issue:**
N/A (documentation improvement only)
**Dependencies:**
None
## Description
This PR adds documentation for the new ZeusDB vector store integration
with LangChain.
## Motivation
ZeusDB is a high-performance vector database (Python/Rust backend)
designed for AI applications that need fast similarity search and
real-time vector ops. This integration brings ZeusDB's capabilities to
the LangChain ecosystem, giving developers another production-oriented
option for vector storage and retrieval.
**Key Features:**
- **User-Friendly Python API**: Intuitive interface that integrates
seamlessly with Python ML workflows
- **High Performance**: Powered by a robust Rust backend for
lightning-fast vector operations
- **Enterprise Logging**: Comprehensive logging capabilities for
monitoring and debugging production systems
- **Advanced Features**: Includes product quantization and persistence
capabilities
- **AI-Optimized**: Purpose-built for modern AI applications and RAG
pipelines
## Changes
- Added provider documentation:
`docs/docs/integrations/providers/zeusdb.mdx` (installation, setup).
- Added vector store documentation:
`docs/docs/integrations/vectorstores/zeusdb.ipynb` (quickstart for
creating/querying a ZeusDBVectorStore).
- Registered langchain-zeusdb in `libs/packages.yml` for discovery.
## Target users
- AI/ML engineers building RAG pipelines
- Data scientists working with large document collections
- Developers needing high-throughput vector search
- Teams requiring near real-time vector operations
## Testing
- Followed LangChain's "How to add standard tests to an integration"
guidance.
- Code passes format, lint, and test checks locally.
- Tested with LangChain Core 0.3.74
- Works with Python 3.10 to 3.13
## Package Information
**PyPI:** https://pypi.org/project/langchain-zeusdb
**Github:** https://github.com/ZeusDB/langchain-zeusdb
## Summary
- Add comprehensive type hints to the MyInMemoryStore example code in
BaseStore docstring
- Improve documentation quality and educational value for developers
- Align with LangChain's coding standards requiring type hints on all
Python code
## Changes Made
- Added return type annotations to all methods (__init__, mget, mset,
mdelete, yield_keys)
- Added parameter type annotations using proper generic types (Sequence,
Iterator)
- Added instance variable type annotation for the store attribute
- Used modern Python union syntax (str | None) for optional types
## Test Plan
- Verified Python syntax validity with ast.parse()
- No functional changes to actual code, only documentation improvements
- Example code now follows best practices and coding standards
This change improves the educational value of the example code and
ensures consistency with LangChain's requirement that "All Python code
MUST include type hints and return types" as specified in the
development guidelines.
---------
Co-authored-by: sadiqkhzn <sadiqkhzn@users.noreply.github.com>
Co-authored-by: Mason Daugherty <mason@langchain.dev>
**Description:**
Introduces documentation notebooks for AI/ML API integration covering
the following use cases:
- Chat models (`ChatAimlapi`)
- Text completion models (`AimlapiLLM`)
- Provider usage examples
- Text embedding models (`AimlapiEmbeddings`)
Additionally, adds the `langchain-aimlapi` package entry to
`libs/packages.yml` for package management.
This PR aims to provide a comprehensive starting point for developers
integrating AI/ML API models with LangChain via the new
`langchain-aimlapi` package.
**Issue:** N/A
**Dependencies:** None
**Twitter handle:** @aimlapi
---
### **To-Do Before Submitting PR:**
* [x] Run `make format`
* [x] Run `make lint`
* [x] Confirm all documentation notebooks are in
`docs/docs/integrations/`
* [x] Double-check `libs/packages.yml` has the correct repo path
* [x] Confirm no `pyproject.toml` modifications were made unnecessarily
Co-authored-by: Mason Daugherty <mason@langchain.dev>
**Description:**
This PR updated links to the latest Anthropic documentation. Changes
include revised links for model overview, tool usage, web search tool,
text editor tool, and more.
**Issue:**
N/A
**Dependencies:**
None
**Twitter handle:**
N/A
Thank you for contributing to LangChain! Follow these steps to mark your
pull request as ready for review. **If any of these steps are not
completed, your PR will not be considered for review.**
- [x] **feat(docs)**: add Bigtable Key-value store doc
- [X] **feat(docs)**: add Bigtable Vector store doc
This PR adds a doc for Bigtable and LangChain Key-value store
integration. It contains guides on how to add, delete, get, and yield
key-value pairs from Bigtable Key-value Store for LangChain.
- [x] **Lint and test**: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified. **We will not consider
a PR unless these three are passing in CI.** See [contribution
guidelines](https://python.langchain.com/docs/contributing/) for more.
Additional guidelines:
- Make sure optional dependencies are imported within a function.
- Please do not add dependencies to `pyproject.toml` files (even
optional ones) unless they are **required** for unit tests.
- Most PRs should not touch more than one package.
- Changes should be backwards compatible.
---------
Co-authored-by: Mason Daugherty <mason@langchain.dev>
# feat(integrations): Add Timbr tools integration
## DESCRIPTION
This PR adds comprehensive documentation and integration support for
Timbr's semantic layer tools in LangChain.
[Timbr](https://timbr.ai/) provides an ontology-driven semantic layer
that enables natural language querying of databases through
business-friendly concepts. It connects raw data to governed business
measures for consistent access across BI, APIs, and AI applications.
[`langchain-timbr`](https://pypi.org/project/langchain-timbr/) is a
Python SDK that extends
[LangChain](https://github.com/WPSemantix/Timbr-GenAI/tree/main/LangChain)
and
[LangGraph](https://github.com/WPSemantix/Timbr-GenAI/tree/main/LangGraph)
with custom agents, chains, and nodes for seamless integration with the
Timbr semantic layer. It enables converting natural language prompts
into optimized semantic-SQL queries and executing them directly against
your data.
**What's Added:**
- Complete integration documentation for `langchain-timbr` package
- Tool documentation page with usage examples and API reference
**Integration Components:**
- `IdentifyTimbrConceptChain` - Identify relevant concepts from user
prompts
- `GenerateTimbrSqlChain` - Generate SQL queries from natural language
- `ValidateTimbrSqlChain` - Validate queries against knowledge graph
schemas
- `ExecuteTimbrQueryChain` - Execute queries against semantic databases
- `GenerateAnswerChain` - Generate human-readable answers from results
## Documentation Added
- `/docs/integrations/providers/timbr.mdx` - Provider overview and
configuration
- `/docs/integrations/tools/timbr.ipynb` - Comprehensive tool usage
examples
## Links
- [PyPI Package](https://pypi.org/project/langchain-timbr/)
- [GitHub Repository](https://github.com/WPSemantix/langchain-timbr)
- [Official
Documentation](https://docs.timbr.ai/doc/docs/integration/langchain-sdk/)
---------
Co-authored-by: Mason Daugherty <mason@langchain.dev>
**Description:** Adds documentation for ZenRows integration with
LangChain, including provider overview and detailed tool documentation.
ZenRows is an enterprise-grade web scraping solution that enables
LangChain agents to extract web content at scale with advanced features
like JavaScript rendering, anti-bot bypass, geo-targeting, and multiple
output formats.
This PR includes:
- Provider documentation
(`docs/docs/integrations/providers/zenrows.ipynb`)
- Tool documentation
(`docs/docs/integrations/tools/zenrows_universal_scraper.ipynb`)
- Complete usage examples and API reference links
**Issue:** N/A
**Dependencies:**
- [langchain-zenrows](https://github.com/ZenRows-Hub/langchain-zenrows)
package (external, available on
[PyPI](https://pypi.org/project/langchain-zenrows/))
- No changes to core LangChain dependencies
**LinkedIn handle:** https://www.linkedin.com/company/zenrows/
---------
Co-authored-by: Mason Daugherty <mason@langchain.dev>
Adding Oracle Generative AI as one of the providers for langchain.
Updated the old examples in the documentation with the new working
examples.
---------
Co-authored-by: Vishal Karwande <vishalkarwande@Vishals-MacBook-Pro.local>
Co-authored-by: Mason Daugherty <mason@langchain.dev>
**Description:** Fixes a small typo in `_get_document_with_hash` inside
`libs/core/langchain_core/indexing/api.py`.
**Issue:** N/A (no related issue)
**Dependencies:** None
Oversight when moving back to basic function call for
`modify_model_request` rather than implementation as its own node.
Basic test right now failing on main, passing on this branch
Revealed a gap in testing. Will write up a more robust test suite for
basic middleware features.
### Description
* Replace the Mermaid graph node label escaping logic
(`_escape_node_label`) with `_to_safe_id`, which converts a string into
a unique, Mermaid-compatible node id. Ensures nodes with special
characters always render correctly.
**Before**
* Invalid characters (e.g. `开`) replaced with `_`. Causes collisions
between nodes with names that are the same length and contain all
non-safe characters:
```python
_escape_node_label("开") # '_'
_escape_node_label("始") # '_' same as above, but different character passed in. not a unique mapping.
```
**After**
```python
_to_safe_id("开") # \5f00
_to_safe_id("始") # \59cb unique!
```
### Tests
* Rename `test_graph_mermaid_escape_node_label()` to
`test_graph_mermaid_to_safe_id()` and update function logic to use
`_to_safe_id`
* Add `test_graph_mermaid_special_chars()`
### Issue
Fixeslangchain-ai/langgraph#6036
Description: Fixes a bug in RunnableRetry where .batch / .abatch could
return misordered outputs (e.g. inputs [0,1,2] yielding [1,1,2]) when
some items succeeded on an earlier attempt and others were retried. Root
cause: successful results were stored keyed by the index within the
shrinking “pending” subset rather than the original input index, causing
collisions and reordered/duplicated outputs after retries. Fix updates
_batch and _abatch to:
- Track remaining original indices explicitly.
- Call underlying batch/abatch only on remaining inputs.
- Map results back to original indices.
- Preserve final ordering by reconstructing outputs in original
positional order.
Issue: Fixes#21326
Tests:
- Added regression tests: test_retry_batch_preserves_order and
test_async_retry_batch_preserves_order asserting correct ordering after
a single controlled failure + retry.
- Existing retry tests still pass.
Dependencies:
- None added or changed.
---------
Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>
**Description:** Fixes infinite recursion issue in JSON schema
dereferencing when objects contain both $ref and other properties (e.g.,
nullable, description, additionalProperties). This was causing Apollo
MCP server schemas to hang indefinitely during tool binding.
**Problem:**
- Commit fb5da8384 changed the condition from `set(obj.keys()) ==
{"$ref"}` to `"$ref" in set(obj.keys())`
- This caused objects with $ref + other properties to be treated as pure
$ref nodes
- Result: other properties were lost and infinite recursion occurred
with complex schemas
**Solution:**
- Restore pure $ref detection for objects with only $ref key
- Add proper handling for mixed $ref objects that preserves all
properties
- Merge resolved reference content with other properties
- Maintain cycle detection to prevent infinite recursion
**Impact:**
- Fixes Apollo MCP server schema integration
- Resolves tool binding infinite recursion with complex GraphQL schemas
- Preserves backward compatibility with existing functionality
- No performance impact - actually improves handling of complex schemas
**Issue:** Fixes#32511
**Dependencies:** None
**Testing:**
- Added comprehensive unit tests covering mixed $ref scenarios
- All existing tests pass (1326 passed, 0 failed)
- Tested with realistic Apollo GraphQL schemas
- Stress tested with 100 iterations of complex schemas
**Verification:**
- ✅ `make format` - All files properly formatted
- ✅ `make lint` - All linting checks pass
- ✅ `make test` - All 1326 unit tests pass
- ✅ No breaking changes - full backwards compatibility maintained
---------
Co-authored-by: Marcus <marcus@Marcus-M4-MAX.local>
Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>
