---
title: "Submit Session Followup"
method: POST
path: "/v1/store/chat-sessions/{chat_session_id}/followup"
tags: ["store"]
---

# Submit Session Followup

`POST /v1/store/chat-sessions/{chat_session_id}/followup`

## Request

- Base URL: `https://api.quadrillion.io` (the document declares no server; this is the origin it was published from)
- URL: `https://api.quadrillion.io/v1/store/chat-sessions/{chat_session_id}/followup`
- Auth: none declared

HTTP twin of the ``session_followup`` socket handler, for detached runs.

Queues a user turn and wakes the drain loop without a socket. The
synchronous 202 replaces the socket ack, so a detached client cannot lose
an ack under burst the way a socket emit can. Dedupe lives inside
``persist_and_announce_queued_followup``; a replayed ``call_id`` returns
the original id without a second row.

## Path parameters

- `chat_session_id` string, required

## Request body

- SessionFollowupRequest
  - `message` string, required
  - `display_message` string, nullable
  - `call_id` string, nullable
  - `gen_args` object, nullable

## Response `202`

Successful Response

- unknown

## Other responses

- `422`: Validation Error

## Changes

- **2026-09-18** `abf76937a751`: 2 info
  - added the optional property `detail/items/ctx` to the response with the `422` status
  - added the optional property `detail/items/input` to the response with the `422` status
- **2026-08-22** `c53108d35a70`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/quadrillion/apis/quadrillion-cloud-api/changes/v1/store/chat-sessions/:chat_session_id/followup/post.md)

---

[API](https://skmtc.dev/quadrillion/apis/quadrillion-cloud-api.md) - [All operations](https://skmtc.dev/quadrillion/apis/quadrillion-cloud-api/llms.txt) - [OpenAPI document](https://skmtc.dev/quadrillion/apis/quadrillion-cloud-api/revisions/2e1425e0e054?raw)