feat: update docs w/ new runtime attributes and utils (#3420)

see langchain-ai/langgraph#7363 for impl details

---------

Co-authored-by: Hunter Lovell <40191806+hntrl@users.noreply.github.com>

Author: sydney-runkle

src/oss/deepagents/async-subagents.mdx

@@ -7,19 +7,15 @@ Async subagents let a supervisor agent launch background tasks that return immed
 
 This builds on [subagents](/oss/deepagents/subagents), which run synchronously and block the supervisor until completion. Use async subagents when tasks are long-running, parallelizable, or need mid-flight steering.
 
-<Warning>
+<Note>
 :::python
-Async subagents are a preview feature targeted for `deepagents` 0.5.0. You can try them now by installing a prerelease version. Preview features are under active development and are not recommended for production use.
-
-For Python, install the `0.5.0a1` prerelease with `--pre` or `--allow-prereleases`.
+Async subagents are a preview feature available in `deepagents` 0.5.0. Preview features are under active development and APIs may change.
 :::
 
 :::js
-Async subagents are a preview feature targeted for `deepagents` 1.9.0. You can try them now by installing a prerelease version. Preview features are under active development and are not recommended for production use.
-
-For JavaScript, install the prerelease version explicitly, for example `deepagents@1.9.0-alpha.0`.
+Async subagents are a preview feature available in `deepagents` 1.9.0. Preview features are under active development and APIs may change.
 :::
-</Warning>
+</Note>
 
 ```mermaid
 graph TB

src/oss/deepagents/backends.mdx

@@ -220,62 +220,72 @@ NamespaceFactory = Callable[[BackendContext], tuple[str, ...]]
 
 The `BackendContext` provides:
 - `ctx.runtime.context` — User-supplied context passed via LangGraph's [context schema](https://langchain-ai.github.io/langgraph/concepts/runtime/) (for example, `user_id`)
+:::python
+- `ctx.runtime.server_info` — Server-specific metadata when running on LangGraph Server (assistant ID, graph ID, authenticated user)
+- `ctx.runtime.execution_info` — Execution identity information (thread ID, run ID, checkpoint ID)
+:::
+:::js
+- `ctx.runtime.serverInfo` — Server-specific metadata when running on LangGraph Server (assistant ID, graph ID, authenticated user)
+- `ctx.runtime.executionInfo` — Execution identity information (thread ID, run ID, checkpoint ID)
+:::
 - `ctx.state` — Current agent state
 
-For `assistant_id` and `thread_id`, use `langgraph.config.get_config()` inside the factory — these are available in LangGraph config metadata but not on the context schema.
+:::python
+<Note>
+`ctx.runtime.server_info` and `ctx.runtime.execution_info` require `deepagents>=0.5.0`.
+</Note>
+:::
+
+:::js
+<Note>
+`ctx.runtime.serverInfo` and `ctx.runtime.executionInfo` require `deepagents>=1.9.0`.
+</Note>
+:::
 
 **Common namespace patterns:**
 
 :::python
 ```python
-from langgraph.config import get_config
 from deepagents.backends import StoreBackend
 
 # Per-user: each user gets their own isolated storage
 backend = StoreBackend(
-    namespace=lambda ctx: (ctx.runtime.context.user_id,),
+    namespace=lambda ctx: (ctx.runtime.server_info.user.identity,),  # [!code highlight]
 )
 
 # Per-assistant: all users of the same assistant share storage
 backend = StoreBackend(
     namespace=lambda ctx: (
-        get_config()["metadata"]["assistant_id"],
+        ctx.runtime.server_info.assistant_id,  # [!code highlight]
     ),
 )
 
 # Per-thread: storage scoped to a single conversation
 backend = StoreBackend(
     namespace=lambda ctx: (
-        get_config()["configurable"]["thread_id"],
+        ctx.runtime.execution_info.thread_id,  # [!code highlight]
     ),
 )
 ```
 :::
 
 :::js
 ```typescript
-import { getConfig } from "@langchain/langgraph";
 import { StoreBackend } from "deepagents";
 
 // Per-user: each user gets their own isolated storage
 const backend = new StoreBackend({
-  namespace: (ctx) => [ctx.runtime.context.userId],
+  namespace: (ctx) => [ctx.runtime.serverInfo.user.identity],  // [!code highlight]
 });
 
 // Per-assistant: all users of the same assistant share storage
 const backend = new StoreBackend({
-  namespace: (ctx) => {
-    const config = getConfig();
-    return [config.metadata.assistantId];
-  },
+  namespace: (ctx) => [ctx.runtime.serverInfo.assistantId],  // [!code highlight]
 });
 
 // Per-thread: storage scoped to a single conversation
 const backend = new StoreBackend({
-  namespace: (ctx) => {
-    const config = getConfig();
-    return [config.configurable.threadId];
-  },
+  namespace: (ctx) => [ctx.runtime.executionInfo.threadId],  // [!code highlight]
 });
 ```
 :::