Merge branch 'main' into add-link-checking

Author: lnhsingh

src/oss/langchain/agents.mdx

@@ -535,6 +535,29 @@ const result = await agent.invoke(
 For more details on message types and formatting, see [Messages](/oss/langchain/messages). For comprehensive middleware documentation, see [Middleware](/oss/langchain/middleware).
 </Tip>
 
+## Invocation
+
+You can invoke an agent by passing an update to its [state](/oss/langgraph/graph-api#state). All agents include a [sequence of messages](/oss/langgraph/use-graph-api#messagesstate) in their state; to invoke the agent, pass a new message:
+
+:::python
+```python
+result = agent.invoke(
+    {"messages": [{"role": "user", "content": "What's the weather in San Francisco?"}]}
+)
+```
+:::
+:::js
+```typescript
+await agent.invoke({
+  messages: [{ role: "user", content: "What's the weather in San Francisco?" }],
+})
+```
+:::
+
+For streaming steps and / or tokens from the agent, refer to the [streaming](/oss/langchain/streaming) guide.
+
+Otherwise, the agent follows the LangGraph [Graph API](/oss/langgraph/use-graph-api) and supports all associated methods.
+
 ## Advanced concepts
 
 ### Structured output

src/oss/langchain/tools.mdx

@@ -15,6 +15,12 @@ Many AI applications interact with users via natural language. However, some use
 
 Tools are components that [agents](/oss/langchain/agents) call to perform actions. They extend model capabilities by letting them interact with the world through well-defined inputs and outputs. Tools encapsulate a callable function and its input schema. These can be passed to compatible [chat models](/oss/langchain/models), allowing the model to decide whether to invoke a tool and with what arguments. In these scenarios, tool calling enables models to generate requests that conform to a specified input schema.
 
+<Note>
+**Server-side tool use**
+
+Some chat models (e.g., [OpenAI](/oss/integrations/chat/openai), [Anthropic](/oss/integrations/chat/anthropic), and [Gemini](/oss/integrations/chat/google_generative_ai)) feature [built-in tools](/oss/langchain/models#server-side-tool-use) that are executed server-side, such as web search and code interpreters. Refer to the [provider overview](/oss/integrations/providers/overview) to learn how to access these tools with your specific chat model.
+</Note>
+
 ## Create tools
 
 ### Basic tool definition