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Author SHA1 Message Date
bc230328ba Update docs/docs/agents/models.md
Co-authored-by: Lauren Hirata Singh <lauren@langchain.dev>
2025-07-30 14:23:21 -04:00
6a53669eeb Apply suggestions from code review
Co-authored-by: Sydney Runkle <54324534+sydney-runkle@users.noreply.github.com>
2025-07-28 15:08:01 -04:00
Eugene Yurtsev 95edac5e03 x 2025-07-28 14:30:42 -04:00
Eugene Yurtsev 6d380dfb41 x 2025-07-28 14:28:39 -04:00
Eugene Yurtsev d6119d55e3 x 2025-07-28 12:51:35 -04:00
8 changed files with 221 additions and 84 deletions
+5 -10
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@@ -310,12 +310,6 @@ def _highlight_code_blocks(markdown: str) -> str:
return markdown
TARGET_LANGUAGE = os.environ.get("TARGET_LANGUAGE", "python")
if TARGET_LANGUAGE not in {"python", "js"}:
raise ValueError(f"TARGET_LANGUAGE must be 'python' or 'js', got {TARGET_LANGUAGE}")
def _on_page_markdown_with_config(
markdown: str,
page: Page,
@@ -338,15 +332,16 @@ def _on_page_markdown_with_config(
markdown = _highlight_code_blocks(markdown)
# Apply conditional rendering for code blocks
markdown = _apply_conditional_rendering(markdown, TARGET_LANGUAGE)
if TARGET_LANGUAGE == "js":
target_language = kwargs.get("target_language", "python")
markdown = _apply_conditional_rendering(markdown, target_language)
if target_language == "js":
markdown = _resolve_cross_references(markdown, JS_LINK_MAP)
elif TARGET_LANGUAGE == "python":
elif target_language == "python":
# Via a dedicated plugin
pass
else:
raise ValueError(
f"Unsupported target language: {TARGET_LANGUAGE}. "
f"Unsupported target language: {target_language}. "
"Supported languages are 'python' and 'js'."
)
+6 -13
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@@ -8,7 +8,7 @@ Context includes *any* data outside the message list that can shape behavior. Th
- Internal state updated during a multi-step reasoning process.
- Persistent memory or facts from previous interactions.
LangGraph provides **three** primary ways to manage context:
LangGraph provides **three** primary ways to supply context:
| Type | Description | Mutable? | Lifetime |
|------------------------------------------------------------------------------|-----------------------------------------------|----------|-------------------------|
@@ -18,21 +18,14 @@ LangGraph provides **three** primary ways to manage context:
### Runtime Context
Runtime context is for immutable data like user metadata, tools, db connections, etc. Use this when you have values that don't change mid-run.
!!! note "`config['configurable']` -> `runtime.context`"
!!! version-added "New in LangGraph v0.6: `Runtime.context` replaces `config['configurable']`"
In LangGraph < v1.0, static runtime context was passed via the `config['configurable']` key, paired with a `config_schema` argument
to `StateGraph` or `Pregel`. This is now deprecated and will be removed in v2.0.
The `Runtime` object is recommended to access static context and runtime-specific information like the store and stream writer.
As of LangGraph v1.0, the Runtime object is recommended to access static context and runtime-specific information like the store and stream writer.
!!! note
Runtime context refers to local context: data and dependencies your code needs to run. It does not refer to:
* The LLM context, which is the data passed into the LLM's prompt.
* The "context window", which is the maximum number of tokens that can be passed to the LLM.
You likely want to use the local context to optimize the LLM's context window. For example, you
could use a user id to fetch a user's name and information from a database to populate the context window with relevant memories.
Runtime context is for immutable data like user metadata or API keys. Use this when you have values that don't change mid-run.
Specify static context via the `context` argument to `invoke` / `stream`, which is reserved for this purpose:
+98
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@@ -70,6 +70,104 @@ When using `create_react_agent` you can specify the model by its name string, wh
)
```
### Dynamic model selection
Pass a callable function to `create_react_agent` to dynamically select the model at runtime. This is useful for scenarios where you want to choose a model based on user input, configuration settings, or other runtime conditions.
The selector function must return an instance of a `BaseChatModel`. If you're using tools, you must bind the tools to the model within the selector function.
```python
openai_model = init_chat_model("openai:gpt-4o")
anthropic_model = init_chat_model("anthropic:claude-sonnet-4-20250514")
# highlight-next-line
def select_model(state, runtime: Runtime[CustomContext]) -> BaseChatModel:
if runtime.context.provider == "anthropic":
model = anthropic_model
elif runtime.context.provider == "openai":
model = openai_model
else:
raise ValueError(f"Unsupported provider: {runtime.context.provider}")
# With dynamic model selection, you must bind tools explicitly
# highlight-next-line
return model.bind_tools(tools_to_use)
agent = create_react_agent(
# highlight-next-line
select_model,
tools=all_known_tools
)
```
!!! version-added "New in LangGraph v0.6"
??? example "Extended example: dynamically select model and tools"
```python
from dataclasses import dataclass
from typing import Literal
from langchain.chat_models import init_chat_model
from langchain_core.language_models import BaseChatModel
from langchain_core.tools import tool
from langgraph.prebuilt import create_react_agent
from langgraph.prebuilt.chat_agent_executor import AgentState
from langgraph.runtime import Runtime
# Define the runtime context
@dataclass
class CustomContext:
provider: Literal["anthropic", "openai"]
@tool
def weather() -> str:
"""Returns the current weather conditions."""
return "It's nice and sunny."
# Initialize models
openai_model = init_chat_model("openai:gpt-4o")
anthropic_model = init_chat_model("anthropic:claude-sonnet-4-20250514")
@dataclass
class CustomContext:
provider: Literal["anthropic", "openai"]
# Initialize models
openai_model = init_chat_model("openai:gpt-4o")
anthropic_model = init_chat_model("anthropic:claude-sonnet-4-20250514")
# Selector function for model choice
def select_model(state: AgentState, runtime: Runtime[CustomContext]) -> BaseChatModel:
if runtime.context.provider == "anthropic":
model = anthropic_model
elif runtime.context.provider == "openai":
model = openai_model
else:
raise ValueError(f"Unsupported provider: {runtime.context.provider}")
# With dynamic model selection, you must bind tools explicitly
return model.bind_tools([weather])
# Create agent with dynamic model selection
agent = create_react_agent(select_model, tools=[weather])
# Invoke with context to select model
output = agent.invoke(
{
"messages": [
{
"role": "user",
"content": "Which model is handling this?",
}
]
},
context=CustomContext(provider="openai"),
)
print(output["messages"][-1].text())
```
## Advanced model configuration
### Disable streaming
@@ -4,9 +4,6 @@
---
## v0.2.109 (2025-07-28)
- Fixed an issue where missing config schema occurred when `config_type` was not set.
## v0.2.108 (2025-07-28)
- Added compatibility for langgraph v0.6, including new context API support and a migration to enhance context handling in assistant operations.
+1 -1
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@@ -28,7 +28,7 @@ To review, edit, and approve tool calls in an agent or workflow, [use LangGraph'
There are two ways to pause a graph:
- [Dynamic interrupts](../how-tos/human_in_the_loop/add-human-in-the-loop.md#pause-using-interrupt): Use `interrupt` to pause a graph from inside a specific node, based on the current state of the graph.
- [Static interrupts](../how-tos/human_in_the_loop/add-human-in-the-loop.md#debug-with-interrupts): Use `interrupt_before` and `interrupt_after` to pause the graph at pre-defined points, either before or after a node executes.
- [Static interrupts](../how-tos/human_in_the_loop/add-human-in-the-loop.md#debug-with-interrupts): Use `interrupt_before` and `interrupt_after` to pause the graph at defined points, either before or after a node executes.
<figure markdown="1">
![image](./img/breakpoints.png){: style="max-height:400px"}
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Before

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@@ -128,7 +128,7 @@ print(graph.invoke(Command(resume="Edited text"), config=config)) # (7)!
!!! tip "New in 0.4.0"
`__interrupt__` is a special key that will be returned when running the graph if the graph is interrupted. Support for `__interrupt__` in `invoke` and `ainvoke` has been added in version 0.4.0. If you're on an older version, you will only see `__interrupt__` in the result if you use `stream` or `astream`. You can also use `graph.get_state(thread_id)` to get the interrupt value(s).
`__interrupt__` is a special key that will be returned when running the graph if the graph is interrupted. Support for `__interrupt__` in `invoke` and `ainvoke` has been added in version 0.4.0. If you're on an older version, you will only see `__interrupt__` in the result if you use `stream` or `astream`. You can also use `graph.get_state(thread_id)` to get the interrupt value.
!!! warning
@@ -145,67 +145,19 @@ To resume execution, use the [`Command`][langgraph.types.Command] primitive, whi
graph.invoke(Command(resume={"age": "25"}), thread_config)
```
## Resuming Multiple interrupts
### Resume multiple interrupts with one invocation
When nodes with interrupt conditions are run in parallel, it's possible to have multiple interrupts in the task queue.
For example, the following graph has two nodes run in parallel that require human input:
<figure markdown="1">
![image](../assets/human_in_loop_parallel.png){: style="max-height:400px"}
</figure>
Once your graph has been interrupted and is stalled, you can resume all the interrupts at once with `Command.resume`, passing a dictionary mapping of interrupt ids to resume values.
If you have multiple interrupts in the task queue, you can use `Command.resume` with a dictionary mapping of interrupt ids to resume with a single `invoke` / `stream` call.
For example, once your graph has been interrupted (multiple times, theoretically) and is stalled:
```python
from typing import TypedDict
import uuid
from langchain_core.runnables import RunnableConfig
from langgraph.checkpoint.memory import InMemorySaver
from langgraph.constants import START
from langgraph.graph import StateGraph
from langgraph.types import interrupt, Command
class State(TypedDict):
text_1: str
text_2: str
def human_node_1(state: State):
value = interrupt({"text_to_revise": state["text_1"]})
return {"text_1": value}
def human_node_2(state: State):
value = interrupt({"text_to_revise": state["text_2"]})
return {"text_2": value}
graph_builder = StateGraph(State)
graph_builder.add_node("human_node_1", human_node_1)
graph_builder.add_node("human_node_2", human_node_2)
# Add both nodes in parallel from START
graph_builder.add_edge(START, "human_node_1")
graph_builder.add_edge(START, "human_node_2")
checkpointer = InMemorySaver()
graph = graph_builder.compile(checkpointer=checkpointer)
thread_id = str(uuid.uuid4())
config: RunnableConfig = {"configurable": {"thread_id": thread_id}}
result = graph.invoke(
{"text_1": "original text 1", "text_2": "original text 2"}, config=config
)
# Resume with mapping of interrupt IDs to values
resume_map = {
i.id: f"edited text for {i.value['text_to_revise']}"
for i in result["__interrupt__"]
i.id: f"human input for prompt {i.value}"
for i in parent.get_state(thread_config).interrupts
}
print(graph.invoke(Command(resume=resume_map), config=config))
# > {'text_1': 'edited text for original text 1', 'text_2': 'edited text for original text 2'}
parent_graph.invoke(Command(resume=resume_map), config=thread_config)
```
## Common patterns
@@ -1075,7 +1027,7 @@ def node_in_parent_graph(state: State):
{'parent_node': {'state_counter': 1}}
```
### Using multiple interrupts in a single node
### Using multiple interrupts
Using multiple interrupts within a **single** node can be helpful for patterns like [validating human input](#validate-human-input). However, using multiple interrupts in the same node can lead to unexpected behavior if not handled carefully.
+102
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@@ -66,6 +66,108 @@ agent = create_react_agent(
agent.invoke({"messages": [{"role": "user", "content": "what's 42 x 7?"}]})
```
### Dynamically select tools
Configure tool availability at runtime based on context:
```python
from langgraph.runtime import Runtime
@dataclass
class CustomContext:
tools: list[Literal["weather", "compass"]]
# highlight-next-line
def configure_model(state: AgentState, runtime: Runtime[CustomContext]):
"""Configure the model with tools based on runtime context."""
selected_tools = [
tool
for tool in [weather, compass]
if tool.name in runtime.context.tools
]
return model.bind_tools(selected_tools)
agent = create_react_agent(
# Dynamically configure the model with tools based on runtime context
# highlight-next-line
configure_model,
# Initialize with all tools available
# highlight-next-line
tools=[weather, compass]
)
```
!!! version-added "Supported with langgraph>=0.6"
??? example "Extended example: dynamically select tools based on context"
```python
from dataclasses import dataclass
from typing import Literal
from langchain.chat_models import init_chat_model
from langchain_core.tools import tool
from langgraph.prebuilt import create_react_agent
from langgraph.prebuilt.chat_agent_executor import AgentState
from langgraph.runtime import Runtime
@dataclass
class CustomContext:
tools: list[Literal["weather", "compass"]]
@tool
def weather() -> str:
"""Returns the current weather conditions."""
return "It's nice and sunny."
@tool
def compass() -> str:
"""Returns the direction the user is facing."""
return "North"
model = init_chat_model("anthropic:claude-sonnet-4-20250514")
# highlight-next-line
def configure_model(state: AgentState, runtime: Runtime[CustomContext]):
"""Configure the model with tools based on runtime context."""
selected_tools = [
tool
for tool in [weather, compass]
if tool.name in runtime.context.tools
]
return model.bind_tools(selected_tools)
agent = create_react_agent(
# Dynamically configure the model with tools based on runtime context
# highlight-next-line
configure_model,
# Initialize with all tools available
# highlight-next-line
tools=[weather, compass]
)
output = agent.invoke(
{
"messages": [
{
"role": "user",
"content": "Who are you and what tools do you have access to?",
}
]
},
# highlight-next-line
context=CustomContext(tools=["weather"]), # Only enable the weather tool
)
print(output["messages"][-1].text())
```
## Use in a workflow
If you are writing a custom workflow, you will need to: