---
title: "Serialize And Submit Task Variables Endpoint"
method: POST
path: "/api/task_variables/serialize_and_submit"
tags: ["task_dag_mutations"]
---

# Serialize And Submit Task Variables Endpoint

`POST /api/task_variables/serialize_and_submit`

Persist variable values captured by a runtime after it produced them.

Internal-principal only: the value must originate from a runtime, never
an agent/session (see ``quadrillion.services.VARIABLE_EVIDENCE_INVARIANT``).

## Request body

- SerializeAndSubmitRequest — Raw values pushed from a runtime — a kernel post-run hook, an explicit ``submit_variable`` call, or a script process. Clients send the JSON-decoded value as-is; the server is the source of truth for type classification (see ``quadrillion.services.value_classifier``). This keeps Python, R, and Julia qualia clients in lockstep regardless of how each language natively represents numeric literals. A runtime identifies itself with ``notebook_id`` (kernels) or ``session_id`` (scripts, which have no notebook). At least one is required; when both arrive the notebook wins, as the more specific claim about where the value came from.
  - `notebook_id` string, nullable — Notebook the values were produced in, for kernels.
  - `session_id` string, nullable — Chat session that launched this runtime, for script processes.
  - `variables` object, required
  - `cell_id` string, nullable

## Response `200`

Successful Response

- SerializeAndSubmitResponse
  - `accepted` string[]
  - `rejected` object
  - `tracked` TrackedVariable[]
    - `name` string, required
    - `expected_type` string, nullable, required
    - `task_id` string, required

## Other responses

- `422` — Validation Error

---

[API](https://skmtc.net/quadrillion/apis/quadrillion-cloud-api.md) · [All operations](https://skmtc.net/quadrillion/apis/quadrillion-cloud-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/quadrillion/quadrillion-cloud-api/revisions/dcf9b4550387/schema)