nanobot/docs/python-sdk.md

Python SDK

Use nanobot as a library — no CLI, no gateway, just Python.

Quick Start

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())

Nanobot.from_config() reuses your normal ~/.nanobot/config.json, so the SDK follows the same provider, model, tools, and workspace defaults as the CLI unless you override them.

Use async with when possible so MCP connections and background cleanup work are closed before the event loop exits. If you manage the instance manually, call await bot.aclose() in a finally block.

Common Patterns

Use a specific config or workspace

from nanobot import Nanobot

bot = Nanobot.from_config(
    config_path="~/.nanobot/config.json",
    workspace="/my/project",
)

Isolate conversations with session_key

Different session keys keep independent conversation history:

await bot.run("hi", session_key="user-alice")
await bot.run("hi", session_key="task-42")

Attach hooks for observability

Hooks let you inspect tool calls, streaming, and iteration state without modifying nanobot internals:

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()])

API Reference

Nanobot.from_config(config_path=None, *, workspace=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.

Raises FileNotFoundError if an explicit config path does not exist.

await bot.run(message, *, session_key="sdk:default", hooks=None)

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.
hooks	list[AgentHook] | None	None	Lifecycle hooks for this run only.

await bot.aclose()

Release resources held by the SDK instance, including MCP connections. The async context manager calls this automatically:

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]	Reserved for richer SDK introspection; may be empty in current versions.
messages	list[dict]	Reserved for richer SDK introspection; may be empty in current versions.

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

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})")

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

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:

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

from nanobot.agent import AgentHook


class Censor(AgentHook):
    def finalize_content(self, context, content):
        return content.replace("secret", "***") if content else content

Full Example

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:
    bot = Nanobot.from_config(workspace="/my/project")
    result = await bot.run(
        "Explain the main function",
        session_key="sdk:demo",
        hooks=[TimingHook()],
    )
    print(result.content)


asyncio.run(main())