---
title: "Post Task Artifact"
method: POST
path: "/tasks/{task_id}/artifacts"
---

# Post Task Artifact

`POST /tasks/{task_id}/artifacts`

Post one journal-anchored artifact against a task the caller holds.

## Path parameters

- `task_id` string, required

## Request body

- TaskArtifactPost — Body for POST /tasks/{task_id}/artifacts (#2553). An agent-posted, journal-anchored artifact. ``artifact_type`` selects the payload shape: ``report`` uses ``body`` (markdown); ``table`` uses ``columns`` and ``rows``; ``link`` uses ``url`` and ``link_kind`` (``preview`` / ``dashboard`` / ``document``). ``poster`` is the claim identity: a caller may only post against a task whose claim it holds. There is deliberately no progress field. Progress is a chain-computed projection of journaled work, never postable.
  - `key` string, required
  - `artifact_type` string, required
  - `poster` string, required
  - `body` string
  - `columns` string[]
  - `rows` array[]
    - string[]
  - `url` string
  - `link_kind` string

## Response `201`

Successful Response

- TaskArtifactContentResponse — A posted artifact version plus its decoded content (for rendering). ``content`` carries the type-specific fields (``body`` for a report, ``columns``/``rows`` for a table, ``url``/``kind`` for a link). When the stored blob fails its hash check ``verified`` is False and ``content`` is omitted -- the surface must render *tampered*, never the bytes.
  - `task_id` string, required
  - `key` string, required
  - `artifact_type` string, required
  - `content_hash` string, required
  - `version` integer, required
  - `prev_version_hash` string, required
  - `spine_entry_hash` string, required
  - `journal_index` integer, required
  - `journal_event_hash` string, required
  - `link_kind` string
  - `size` integer
  - `verified` boolean
  - `verify_reason` string
  - `content` object, nullable

## Other responses

- `403` — Caller does not hold the task's claim
- `404` — Task not found
- `413` — Artifact payload exceeds the per-blob cap
- `422` — Invalid artifact payload

---

[API](https://skmtc.net/sipyourdrink-ltd/apis/bernstein-task-server.md) · [All operations](https://skmtc.net/sipyourdrink-ltd/apis/bernstein-task-server/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/sipyourdrink-ltd/bernstein-task-server/versions/86f514b4e920/schema)