Thread

This page describes the Thread type from aion.langgraph.authoring. The Thread object is the main fluent surface for replying, posting, and emitting streaming intents without forcing authors to build raw A2A messages by hand.

Properties

Property	Purpose
`context_id`	Current messaging thread or context identifier
`parent_context_id`	Parent thread or context identifier when one exists
`network`	Originating network or distribution identifier
`default_reply_target`	Canonical reply target derived from the inbound event
`message`	Normalized inbound `Message`, or `None` when no inbound message exists

Methods

Method	Purpose
`from_context(context)`	Class method. Create a `Thread` from an `AionRuntimeContext`
`reply(content, *, metadata=None)`	Add a durable reply to the current thread
`post(content, *, target=None, metadata=None)`	Create an explicit outbound post action
`typing(content, *, metadata=None)`	Emit a stream-only typing or progress intent

reply(...) and post(...) accept the same content categories:

plain text (str)
AIMessage or AIMessageChunk
async iterator of str or AIMessageChunk for streaming replies
a Card object — provider-neutral card document
an a2a.types.Artifact built with url_artifact, file_artifact, or data_artifact

`reply(...)`

reply(...) is intended for the most common case: answer in the same place the inbound message arrived.

from langchain_core.messages import AIMessage, AIMessageChunk
from langgraph.runtime import Runtime

from aion.core.a2a import data_artifact, file_artifact, url_artifact
from aion.core.agent.invocation.card import Card, Text
from aion.core.runtime import AionRuntimeContext
from aion.langgraph.authoring import Thread


async def node(state: State, runtime: Runtime[AionRuntimeContext]) -> dict:
    thread = Thread.from_context(runtime.context)

    # Plain text
    await thread.reply("Thanks. I'm looking into that now.")

    # LangChain message types
    await thread.reply(AIMessage(content="Done."))
    await thread.reply(AIMessageChunk(content="Streaming chunk..."))

    # Async iterator — streamed live, accumulated as a durable reply
    async def generate():
        for word in ["Processing", " your", " request..."]:
            yield word

    await thread.reply(generate())

    # Card — see /sdk/python/messaging/card for all creation modes
    await thread.reply(Card("Report ready").add(Text("All checks passed.")))

    # Artifacts — see /sdk/python/messaging/artifacts for the full reference
    await thread.reply(url_artifact("https://example.com/report.pdf", mime_type="application/pdf", name="report"))
    await thread.reply(file_artifact(pdf_bytes, mime_type="application/pdf", name="report"))
    await thread.reply(data_artifact({"score": 0.95}, name="result"))

    return {}

`post(...)`

post(...) is intended for explicit outbound actions that should remain distinct from the default reply target.

async def node(state: State, runtime: Runtime[AionRuntimeContext]) -> dict:
    thread = Thread.from_context(runtime.context)
    await thread.post("Posting a follow-up note to a different channel.")
    return {}

Unlike reply(...), post(...) should remain explicit in the response buffer so cross-target delivery is never inferred from transcript order alone.

`typing(...)`

typing(content, *, metadata=None) is intended for stream-only live intents. content is a required string — the transient text shown to the user while the agent is working.

async def node(state: State, runtime: Runtime[AionRuntimeContext]) -> dict:
    thread = Thread.from_context(runtime.context)
    await thread.typing("Thinking...")
    return {}

These intents should not replace the durable response precedence. They are best-effort live hints for streaming views.

Python SDK

LangGraph

Google ADK

Properties

Methods

`reply(...)`

`post(...)`

`typing(...)`

​Properties

​Methods

​reply(...)

​post(...)

​typing(...)

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Properties

Methods

`reply(...)`

`post(...)`

`typing(...)`

Related Pages