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+# Nanobot Python SDK: Run an AI Agent from Python
+
+Use nanobot as a Python library. The SDK gives you the same agent runtime used
+by the CLI, but from code: model routing, tools, workspace access, conversation
+history, memory, streaming events, and runtime helpers.
+
+If you have used the OpenAI SDK before, the most important difference is this:
+
+- OpenAI SDK calls a model.
+- nanobot SDK runs an agent around a model.
+
+That means one SDK call can read files, call tools, keep session history, use
+memory, stream progress, and return structured runtime information.
+
+```text
+your Python code
+  -> Nanobot SDK
+    -> agent runtime
+      -> configured model provider
+      -> tools
+      -> workspace
+      -> session history
+      -> memory
+```
+
+## Before You Start
+
+Install and configure nanobot first. If you have not done that yet, follow the
+[Quick Start](quick-start.md) and complete the setup wizard. For SDK-only Python
+environments, install the package with:
+
+```bash
+python -m pip install nanobot-ai
+```
+
+`Nanobot.from_config()` reuses your normal `~/.nanobot/config.json` and
+`~/.nanobot/workspace/`. Provider, model, tools, memory, and session behavior
+match the CLI unless you override them. For the difference between config and
+workspace, see [Concepts: Config vs Workspace](concepts.md#config-vs-workspace).
+
+Before writing SDK code, run the same first-run checks from the main
+[Install and Quick Start](quick-start.md):
+
+```bash
+nanobot status
+```
+
+`nanobot status` should show the config path, workspace path, active model or
+preset, and provider summary. Then send one real message:
+
+```bash
+nanobot agent -m "Hello!"
+```
+
+A normal assistant reply means install, config, provider/model selection, and
+workspace access are all usable. Once that works, the SDK should see the same
+runtime.
+
+## 5-Minute Quick Start
+
+### Ask One Question
+
+```python
+import asyncio
+
+from nanobot import Nanobot
+
+
+async def main() -> None:
+    async with Nanobot.from_config() as bot:
+        result = await bot.run("What time is it in Tokyo?")
+    print(result.content)
+
+
+asyncio.run(main())
+```
+
+Use `async with` when possible so tool connections and background cleanup are
+closed before the event loop exits. If you manage the instance manually, call
+`await bot.aclose()` in a `finally` block.
+
+The SDK is async-first because agent runs may stream tokens, execute tools, and
+wait on external services. In a normal Python script, wrap your async function
+with `asyncio.run(...)` as shown above. In a notebook or another async app, call
+`await bot.run(...)` directly from your existing event loop.
+
+### Inspect What Happened
+
+`bot.run(...)` returns a `RunResult`, not just a string:
+
+```python
+result = await bot.run("Review this repository")
+
+print(result.content)     # final answer
+print(result.tools_used)  # tools the agent used
+print(result.usage)       # token usage when available
+print(result.stop_reason) # why the run stopped
+```
+
+### Continue A Conversation
+
+Use a `session_key` when you want history to carry across turns. Different
+session keys are isolated from each other:
+
+```python
+await bot.run("My name is Alice.", session_key="user:alice")
+result = await bot.run("What is my name?", session_key="user:alice")
+
+print(result.content)
+```
+
+This is the SDK equivalent of giving each user, task, eval case, or workflow
+its own conversation thread.
+
+### Stream A Long Answer
+
+For live output, use `bot.stream(...)`:
+
+```python
+from nanobot import STREAM_EVENT_TEXT_DELTA
+
+async for event in bot.stream("Write a migration plan"):
+    if event.type == STREAM_EVENT_TEXT_DELTA:
+        print(event.delta, end="", flush=True)
+```
+
+Streaming returns structured events, so you can also observe tool calls,
+reasoning chunks, completion, and failures.
+
+## Complete Starter Script
+
+Save this as `sdk_demo.py` after `nanobot agent -m "Hello!"` works:
+
+```python
+import asyncio
+import sys
+
+from nanobot import (
+    STREAM_EVENT_RUN_COMPLETED,
+    STREAM_EVENT_RUN_FAILED,
+    STREAM_EVENT_TEXT_DELTA,
+    STREAM_EVENT_TOOL_STARTED,
+    Nanobot,
+)
+
+
+async def main() -> None:
+    prompt = " ".join(sys.argv[1:]) or "Explain what nanobot is in one paragraph."
+    session_key = "sdk:demo"
+
+    async with Nanobot.from_config() as bot:
+        print(f"model: {bot.runtime.model}")
+        print(f"workspace: {bot.runtime.workspace}")
+        print()
+
+        final_result = None
+        async for event in bot.stream(prompt, session_key=session_key):
+            if event.type == STREAM_EVENT_TEXT_DELTA:
+                print(event.delta, end="", flush=True)
+            elif event.type == STREAM_EVENT_TOOL_STARTED:
+                print(f"\n[tool] {event.name}", flush=True)
+            elif event.type == STREAM_EVENT_RUN_COMPLETED:
+                final_result = event.result
+            elif event.type == STREAM_EVENT_RUN_FAILED:
+                raise RuntimeError(event.error or "nanobot run failed")
+
+        print()
+        if final_result is not None:
+            print(f"\nstop_reason: {final_result.stop_reason}")
+            print(f"tools_used: {final_result.tools_used}")
+            print(f"usage: {final_result.usage}")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
+```
+
+Run it:
+
+```bash
+python sdk_demo.py "List the top-level files in the current workspace."
+```
+
+You should see the configured model, workspace path, streamed assistant text,
+and final run metadata. The exact answer depends on your config and workspace,
+but a file-listing prompt may look like this:
+
+```text
+model: openai/gpt-4.1-mini
+workspace: /Users/alice/.nanobot/workspace
+
+[tool] list_dir
+Here are the top-level files I found...
+
+stop_reason: completed
+tools_used: ['list_dir']
+usage: {'prompt_tokens': ..., 'completion_tokens': ..., 'total_tokens': ...}
+```
+
+This script shows the usual production shape: create one `Nanobot`, choose a
+stable `session_key`, stream events, keep the final `RunResult`, and let
+`async with` close runtime resources.
+
+## Core Concepts
+
+| Concept | Meaning |
+|---------|---------|
+| `Nanobot` | The SDK object that owns one configured agent runtime. |
+| Run | One call to `bot.run(...)`, `bot.run_streamed(...)`, or `bot.stream(...)`. |
+| `session_key` | The conversation history key. Reuse it to continue a thread; change it to isolate a thread. |
+| Workspace | The local directory where file tools and shell tools operate. |
+| Tools | Capabilities the agent may call, such as file access, shell, web, or custom tools from your config. |
+| Memory | Long-term memory files managed by nanobot. |
+| Stream event | A typed event such as `text.delta`, `tool.started`, or `run.completed`. |
+| Model override | A temporary model or model preset used for one SDK instance or one run. |
+
+For most users, the mental model is:
+
+1. Create a `Nanobot` from config.
+2. Pick a `session_key`.
+3. Call `run` or `stream`.
+4. Read `RunResult` or stream events.
+5. Use session/memory/runtime helpers only when you need more control.
+
+## SDK Or OpenAI-Compatible API?
+
+nanobot has two programming surfaces:
+
+| Use | Choose | Why |
+|-----|--------|-----|
+| Python code running in the same process as nanobot | Python SDK | Direct access to `RunResult`, sessions, memory, runtime helpers, hooks, and stream events. |
+| Existing OpenAI-compatible clients, another language, or a separate process | [OpenAI-Compatible API](openai-api.md) | HTTP `/v1/chat/completions` compatibility with familiar client libraries. |
+
+The Python SDK is best when you are writing evals, notebooks, benchmark
+runners, product backends, local scripts, or integrations that should control
+nanobot directly.
+
+The OpenAI-compatible API is best when you already have an HTTP client, want
+process isolation, or need to call nanobot from a non-Python service.
+
+## Common Patterns
+
+### Use a specific config or workspace
+
+Set the workspace when your agent should work inside a specific project:
+
+```python
+from nanobot import Nanobot
+
+async with Nanobot.from_config(workspace="/my/project") as bot:
+    result = await bot.run("Explain the project structure")
+```
+
+Use a custom config when you run multiple nanobot instances or test an isolated
+setup:
+
+```python
+async with Nanobot.from_config(
+    config_path="./bot-a/config.json",
+    workspace="./bot-a/workspace",
+) as bot:
+    result = await bot.run("Hello from bot A")
+```
+
+The config controls what nanobot may use. The workspace is where nanobot keeps
+state for that instance. See [multiple-instances.md](multiple-instances.md) for
+multi-instance CLI and gateway examples.
+
+### Choose a default or per-run model
+
+Set the SDK instance default model when you create the bot:
+
+```python
+bot = Nanobot.from_config(model="openai/gpt-4.1")
+```
+
+Override the model for one run without changing the instance default:
+
+```python
+result = await bot.run("Summarize this file", model="openai/gpt-4.1-mini")
+```
+
+Model presets from `config.json` work the same way:
+
+```python
+bot = Nanobot.from_config(model_preset="fast")
+
+result = await bot.run("Think deeply about this bug", model_preset="reasoning")
+```
+
+`model` and `model_preset` are mutually exclusive.
+
+For first setup, prefer named presets in `config.json`. Mixing an API key from
+one provider with a model ID from another is the most common first-run failure.
+For the exact difference between `provider`, `model`, `apiKey`, and `apiBase`,
+see [Providers: Provider, Model, API Key, and Base URL](providers.md#provider-model-api-key-and-base-url).
+If a run fails before the SDK does anything interesting, confirm the same
+provider and model work with `nanobot agent -m "Hello!"` first.
+
+### Isolate conversations with `session_key`
+
+Different session keys keep independent conversation history:
+
+```python
+await bot.run("hi", session_key="user-alice")
+await bot.run("hi", session_key="task-42")
+```
+
+Use stable keys in product code:
+
+```python
+session_key = f"user:{user_id}"
+result = await bot.run(user_message, session_key=session_key)
+```
+
+Avoid using the default `"sdk:default"` for multiple users or unrelated
+workflows. It is convenient for local experiments, but stable product code
+should choose explicit keys such as `user:<id>`, `project:<id>`, or
+`eval:<case-id>`.
+
+### Handle failures
+
+For a normal non-streamed run, catch exceptions around `bot.run(...)` and inspect
+`RunResult.error` when the runtime returns a structured failure:
+
+```python
+try:
+    result = await bot.run("Review this repo", session_key="project:demo")
+except Exception as exc:
+    print(f"SDK call failed before a result was returned: {exc}")
+else:
+    if result.error:
+        print(f"Agent run failed: {result.error}")
+    else:
+        print(result.content)
+```
+
+For streamed runs, either consume the stream to completion or close it:
+
+```python
+run = await bot.run_streamed("Write a long answer", session_key="task:123")
+try:
+    async for event in run.stream_events():
+        ...
+finally:
+    if not run.done:
+        await run.aclose()
+```
+
+Use `await run.cancel()` when the user presses a stop button or leaves the page
+before the stream finishes.
+
+### Stream long-running output
+
+Use `bot.stream()` when you want Cursor/OpenAI-style live events instead of
+waiting for the final `RunResult`:
+
+```python
+from nanobot import (
+    STREAM_EVENT_RUN_COMPLETED,
+    STREAM_EVENT_TEXT_DELTA,
+    STREAM_EVENT_TOOL_STARTED,
+)
+
+async for event in bot.stream("Review this repository"):
+    if event.type == STREAM_EVENT_TEXT_DELTA:
+        print(event.delta, end="", flush=True)
+    elif event.type == STREAM_EVENT_TOOL_STARTED:
+        print(f"\nusing {event.name}")
+    elif event.type == STREAM_EVENT_RUN_COMPLETED:
+        print("\nfinal:", event.result.content)
+```
+
+Use `run_streamed()` when you also want a handle you can wait on:
+
+```python
+from nanobot import STREAM_EVENT_TEXT_DELTA
+
+run = await bot.run_streamed("Write a detailed migration plan")
+
+async for event in run.stream_events():
+    if event.type == STREAM_EVENT_TEXT_DELTA:
+        print(event.delta, end="", flush=True)
+
+result = await run.wait()
+```
+
+Always either consume the stream, call `await run.wait()` / `await run.text()`,
+or close it with `await run.cancel()` / `await run.aclose()`. Exiting
+`stream_events()` or `bot.stream()` early cancels the underlying run so a
+half-consumed stream cannot leave a background task stuck behind backpressure.
+
+### Import an existing transcript
+
+This is useful for evals, benchmark runners, migrations, and tests.
+
+Use `bot.sessions.ingest()` when you already have a transcript and want it to
+become nanobot session history. Ingesting a transcript does not call the model,
+execute tools, update memory, or compact automatically.
+
+```python
+await bot.sessions.ingest(
+    "eval:case-1",
+    [
+        {
+            "role": "user",
+            "content": "I graduated with a degree in Business Administration.",
+            "timestamp": "2023/05/30 (Tue) 17:27",
+            "source_session_id": "answer_280352e9",
+        },
+        {
+            "role": "assistant",
+            "content": "Congratulations on your degree.",
+            "timestamp": "2023/05/30 (Tue) 17:27",
+        },
+    ],
+    source="longmemeval",
+)
+
+await bot.runtime.compact_session("eval:case-1")
+
+result = await bot.run(
+    "Current Date: 2023/05/30 (Tue) 23:40\n"
+    "Question: What degree did I graduate with?",
+    session_key="eval:case-1",
+)
+print(result.content)
+```
+
+### Attach hooks for observability
+
+Hooks are an advanced escape hatch. Use them when you want custom logging,
+metrics, tracing, or output post-processing without modifying nanobot internals:
+
+```python
+from nanobot.agent import AgentHook, AgentHookContext
+
+
+class AuditHook(AgentHook):
+    async def before_execute_tools(self, context: AgentHookContext) -> None:
+        for tc in context.tool_calls:
+            print(f"[tool] {tc.name}")
+
+
+result = await bot.run("Review this change", hooks=[AuditHook()])
+```
+
+## Where To Go Next
+
+The SDK page is the programming entry point. The fuller conceptual and
+configuration docs remain the source of truth for the runtime around it:
+
+| Need | Read |
+|------|------|
+| First working install and config | [Install and Quick Start](quick-start.md) |
+| Mental model for config, workspace, sessions, tools, and memory | [Concepts](concepts.md) |
+| Provider/model/API key/base URL matching | [Providers and Models](providers.md) |
+| Pasteable provider recipes | [Provider Cookbook](provider-cookbook.md) |
+| Complete configuration reference | [Configuration](configuration.md) |
+| Long-term memory design | [Memory](memory.md) |
+| HTTP API instead of Python SDK | [OpenAI-Compatible API](openai-api.md) |
+| Debugging install, config, provider, or runtime failures | [Troubleshooting](troubleshooting.md) |
+
+## API Reference
+
+### `Nanobot.from_config(config_path=None, *, workspace=None, model=None, model_preset=None)`
+
+Create a `Nanobot` instance from a config file.
+
+| Param | Type | Default | Description |
+|-------|------|---------|-------------|
+| `config_path` | `str \| Path \| None` | `None` | Path to `config.json`. Defaults to `~/.nanobot/config.json`. |
+| `workspace` | `str \| Path \| None` | `None` | Override the workspace directory from config. |
+| `model` | `str \| None` | `None` | Override the instance default model. |
+| `model_preset` | `str \| None` | `None` | Override the instance default model preset from `config.json`. |
+
+Raises `FileNotFoundError` if an explicit config path does not exist.
+Raises `ValueError` if both `model` and `model_preset` are provided.
+
+### `await bot.run(...)`
+
+Run the agent once and return a `RunResult`.
+
+| Param | Type | Default | Description |
+|-------|------|---------|-------------|
+| `message` | `str` | *(required)* | The user message to process. |
+| `session_key` | `str` | `"sdk:default"` | Session identifier for conversation isolation. Different keys get independent history. |
+| `channel` | `str` | `"cli"` | Logical channel label used in runtime context. |
+| `chat_id` | `str` | `"direct"` | Logical chat identifier used in runtime context. |
+| `sender_id` | `str` | `"user"` | Logical sender identifier used in runtime context. |
+| `media` | `list[str] \| None` | `None` | Optional local media paths attached to the message. |
+| `ephemeral` | `bool` | `False` | Run without persisting the turn or compacting session history. |
+| `hooks` | `list[AgentHook] \| None` | `None` | Lifecycle hooks for this run only. |
+| `model` | `str \| None` | `None` | Override the model for this run only. |
+| `model_preset` | `str \| None` | `None` | Override the model preset for this run only. |
+
+`model` and `model_preset` are per-run overrides and do not change
+`bot.runtime.model` after the run completes. They are mutually exclusive.
+
+### `await bot.run_streamed(...)`
+
+Start a streamed agent turn and return a `RunStream`. It accepts the same
+parameters as `bot.run(...)`.
+
+```python
+run = await bot.run_streamed("Generate a long answer")
+
+async for event in run.stream_events():
+    ...
+
+result = await run.wait()
+```
+
+### `bot.stream(...)`
+
+Convenience wrapper around `run_streamed()` for direct event iteration. It
+accepts the same parameters as `bot.run(...)`.
+
+```python
+async for event in bot.stream("Generate a long answer"):
+    ...
+```
+
+### `RunStream`
+
+| Method | Description |
+|--------|-------------|
+| `stream_events()` | Single-consumer async iterator of `StreamEvent` objects. |
+| `await wait()` | Wait for the run to finish and return `RunResult`. |
+| `await text()` | Wait for the run to finish and return `RunResult.content`. |
+| `await cancel()` | Cancel the run and release stream resources. |
+| `await aclose()` | Close the stream; equivalent cleanup primitive for `async with` / manual lifecycle code. |
+
+Normal SDK runs with different session keys may overlap. Runs that use per-run
+`model` or `model_preset` overrides are exclusive while the override is active,
+because the current `AgentLoop` provider/model state is mutable.
+
+### `StreamEvent`
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `type` | `StreamEventType` | Event type, such as `text.delta` or `run.completed`. |
+| `delta` | `str` | Incremental text or reasoning chunk. |
+| `content` | `str` | Completed text segment or final content. |
+| `result` | `RunResult \| None` | Present on `run.completed`. |
+| `name` | `str \| None` | Tool name for tool events. |
+| `tool_call_id` | `str \| None` | Provider tool call id when available. |
+| `arguments` | `dict \| None` | Tool arguments when available. |
+| `iteration` | `int \| None` | Agent loop iteration when available. |
+| `resuming` | `bool \| None` | Whether a text segment ended before more tool work. |
+| `usage` | `dict[str, int]` | Token usage on completion events. |
+| `error` | `str \| None` | Error text on failed events. |
+| `metadata` | `dict` | Additional event metadata. |
+
+Use the exported constants instead of hard-coded strings when possible:
+
+| Constant | Value |
+|----------|-------|
+| `STREAM_EVENT_RUN_STARTED` | `run.started` |
+| `STREAM_EVENT_TEXT_DELTA` | `text.delta` |
+| `STREAM_EVENT_TEXT_COMPLETED` | `text.completed` |
+| `STREAM_EVENT_REASONING_DELTA` | `reasoning.delta` |
+| `STREAM_EVENT_REASONING_COMPLETED` | `reasoning.completed` |
+| `STREAM_EVENT_TOOL_STARTED` | `tool.started` |
+| `STREAM_EVENT_TOOL_COMPLETED` | `tool.completed` |
+| `STREAM_EVENT_TOOL_FAILED` | `tool.failed` |
+| `STREAM_EVENT_RUN_COMPLETED` | `run.completed` |
+| `STREAM_EVENT_RUN_FAILED` | `run.failed` |
+
+`STREAM_EVENT_TYPES` contains all stable v1 event values.
+
+### `await bot.aclose()`
+
+Release resources held by the SDK instance, including tool connections. The async context manager calls this automatically:
+
+```python
+async with Nanobot.from_config() as bot:
+    result = await bot.run("Summarize this repo")
+```
+
+### `RunResult`
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `content` | `str` | The agent's final text response. |
+| `tools_used` | `list[str]` | Tool names used during the run. |
+| `messages` | `list[dict]` | Final message list from the run. |
+| `usage` | `dict[str, int]` | Token usage reported or estimated by the runtime. |
+| `stop_reason` | `str \| None` | Why the run stopped, such as `"completed"` or `"max_iterations"`. |
+| `error` | `str \| None` | Error text when the run failed inside the agent runtime. |
+| `metadata` | `dict` | Outbound metadata such as latency. |
+
+## Session, Memory, And Runtime Helpers
+
+### `bot.sessions`
+
+| Method | Description |
+|--------|-------------|
+| `await ingest(session_key, messages, metadata=None, source=None, save=True)` | Import existing transcript messages without running the model. |
+| `get(session_key)` | Return a `SessionSnapshot`, or `None` if missing. |
+| `list()` | Return compact `SessionInfo` rows. |
+| `export(session_key)` | Return a trusted full `SessionSnapshot`, including model-only runtime context, suitable for JSON serialization. |
+| `await restore(snapshot, session_key=None, save=True)` | Restore a trusted exported snapshot into an empty session; the returned snapshot is display-safe. |
+| `clear(session_key)` | Clear and persist one session. |
+| `delete(session_key)` | Delete one session from disk and cache. |
+| `flush()` | Flush cached sessions to durable storage. |
+
+Ingested messages must include `role` and `content`. Roles may be `user`,
+`assistant`, `tool`, or `system`. Other fields, such as `timestamp`,
+`source_session_id`, or `source_date`, are persisted as message metadata.
+
+`get()` and snapshots returned by ordinary SDK operations are display-safe and omit
+model-only runtime context. `export()` is an explicit backup boundary and includes
+that internal context so `restore()` can preserve the exact model-visible history.
+Do not expose exported snapshots directly to chat users.
+
+### `bot.memory`
+
+| Method | Description |
+|--------|-------------|
+| `read()` | Read `memory/MEMORY.md`. |
+| `write(text)` | Overwrite `memory/MEMORY.md`. |
+| `append_history(text, session_key=None)` | Append one `memory/history.jsonl` entry and return its cursor. |
+| `read_history(session_key=None)` | Read memory history entries, optionally filtered by session key. |
+
+### `bot.runtime`
+
+| Method / Property | Description |
+|-------------------|-------------|
+| `model` | Current runtime model name. |
+| `workspace` | Current runtime workspace path. |
+| `await compact_session(session_key)` | Run token/replay-window consolidation for a session. |
+| `await compact_idle_session(session_key, max_suffix=8)` | Run idle-session compaction and return its summary. |
+
+## Hooks
+
+Hooks let you observe or customize the agent loop. Subclass `AgentHook` and override the methods you need.
+
+### Hook lifecycle
+
+| Method | When |
+|--------|------|
+| `wants_streaming()` | Return `True` if you want token-by-token `on_stream()` callbacks |
+| `before_iteration(context)` | Before each LLM call |
+| `on_stream(context, delta)` | On each streamed token when streaming is enabled |
+| `on_stream_end(context, *, resuming)` | When streaming finishes |
+| `before_execute_tools(context)` | Before tool execution |
+| `after_iteration(context)` | After each iteration |
+| `finalize_content(context, content)` | Transform final output text |
+
+Useful fields on `AgentHookContext` include:
+
+- `iteration`
+- `messages`
+- `response`
+- `usage`
+- `tool_calls`
+- `tool_results`
+- `tool_events`
+- `final_content`
+- `stop_reason`
+- `error`
+
+### Example: audit tool calls
+
+```python
+from nanobot.agent import AgentHook, AgentHookContext
+
+
+class AuditHook(AgentHook):
+    def __init__(self) -> None:
+        super().__init__()
+        self.calls: list[str] = []
+
+    async def before_execute_tools(self, context: AgentHookContext) -> None:
+        for tc in context.tool_calls:
+            self.calls.append(tc.name)
+            print(f"[audit] {tc.name}({tc.arguments})")
+```
+
+```python
+hook = AuditHook()
+result = await bot.run("List files in /tmp", hooks=[hook])
+print(result.content)
+print(f"Tools observed: {hook.calls}")
+```
+
+### Example: receive streaming tokens
+
+```python
+from nanobot.agent import AgentHook, AgentHookContext
+
+
+class StreamingHook(AgentHook):
+    def wants_streaming(self) -> bool:
+        return True
+
+    async def on_stream(self, context: AgentHookContext, delta: str) -> None:
+        print(delta, end="", flush=True)
+
+    async def on_stream_end(self, context: AgentHookContext, *, resuming: bool) -> None:
+        print()
+```
+
+### Compose multiple hooks
+
+Pass multiple hooks when you want to combine behaviors:
+
+```python
+result = await bot.run("hi", hooks=[AuditHook(), MetricsHook()])
+```
+
+Async hook methods are fan-out with error isolation. `finalize_content` is a pipeline: each hook receives the previous hook's output.
+
+### Example: post-process final content
+
+```python
+from nanobot.agent import AgentHook
+
+
+class Censor(AgentHook):
+    def finalize_content(self, context, content):
+        return content.replace("secret", "***") if content else content
+```
+
+## Full Example
+
+```python
+import asyncio
+import time
+
+from nanobot import Nanobot
+from nanobot.agent import AgentHook, AgentHookContext
+
+
+class TimingHook(AgentHook):
+    def __init__(self) -> None:
+        super().__init__()
+        self._started_at = 0.0
+
+    async def before_iteration(self, context: AgentHookContext) -> None:
+        self._started_at = time.perf_counter()
+
+    async def after_iteration(self, context: AgentHookContext) -> None:
+        elapsed_ms = (time.perf_counter() - self._started_at) * 1000
+        print(f"[timing] iteration {context.iteration} took {elapsed_ms:.1f}ms")
+
+
+async def main() -> None:
+    async with Nanobot.from_config(workspace="/my/project") as bot:
+        result = await bot.run(
+            "Explain the main function",
+            session_key="sdk:demo",
+            hooks=[TimingHook()],
+        )
+    print(result.content)
+
+
+asyncio.run(main())
+```