> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bland.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Preview Agent Branch Rebase

> Preview a branch rebase onto the current dev head.

### Overview

Dry-runs a three-way merge of the branch onto dev's current head and reports what a rebase would bring in from dev (`changes`) and where dev and the branch changed the same value differently (`conflicts`). This is a POST but it writes nothing and takes no body. Call it after [Merge Agent Branch](/api-v2/post/agents-id-branches-branch-id-merge) returns `409 BRANCH_BEHIND`, then pass the returned `dev_head_version_id` and a resolution for every conflict to [Rebase Agent Branch](/api-v2/post/agents-id-branches-branch-id-rebase).

Requires an admin, owner, operator, or prompter role.

### Headers

<ParamField header="authorization" type="string" required>
  Your API key for authentication.
</ParamField>

### Path Parameters

<ParamField path="agent_id" type="string" required>
  The agent's unique identifier.
</ParamField>

<ParamField path="branch_id" type="string" required>
  The branch's unique identifier. Must be an open branch on this agent.
</ParamField>

### Response

<ResponseField name="data.dev_head_version_id" type="string | null">
  The dev version the preview ran against. Pass this unchanged to Rebase Agent Branch. `null` when the agent has no dev versions.
</ResponseField>

<ResponseField name="data.up_to_date" type="boolean">
  `true` when the branch's base is already dev's head (or the agent has no dev versions), so there is nothing to rebase and a merge would fast-forward. `changes` and `conflicts` are empty in that case.
</ResponseField>

<ResponseField name="data.auto_merged" type="integer">
  Number of entries in `changes`.
</ResponseField>

<ResponseField name="data.changes" type="array">
  Dev-side edits the branch did not touch. They merge in automatically on rebase; nothing is required from you.

  <Expandable title="change object">
    <ResponseField name="id" type="string">
      Stable identifier, `kind:key` or `kind:key#path`.
    </ResponseField>

    <ResponseField name="kind" type="string">
      One of `node`, `edge`, `setting`, `contact`, `knowledge`.
    </ResponseField>

    <ResponseField name="key" type="string">
      The node or edge ID, or the `settings`, `contact`, or `knowledge` field name.
    </ResponseField>

    <ResponseField name="path" type="string">
      Dot path to the changed value inside that unit. Empty string when the whole unit changed, such as an added or deleted node.
    </ResponseField>

    <ResponseField name="path_labels" type="array">
      Display labels aligned with `path`, with element IDs replaced by names where available.
    </ResponseField>

    <ResponseField name="label" type="string">
      Human-readable name of the unit, such as a node's name or a setting's field name.
    </ResponseField>

    <ResponseField name="base" type="any">
      The value at `path` on the branch's base. Omitted when dev added the value.
    </ResponseField>

    <ResponseField name="theirs" type="any">
      Dev's current value at `path`. Omitted when dev deleted the value.
    </ResponseField>
  </Expandable>
</ResponseField>

<ResponseField name="data.conflicts" type="array">
  Values changed differently on both sides. Each needs a resolution before the rebase succeeds; key your `resolutions` map by the conflict's `id`.

  <Expandable title="conflict object">
    <ResponseField name="id" type="string">
      Stable identifier, `kind:key` or `kind:key#path`. Use it as the key in the `resolutions` body of Rebase Agent Branch.
    </ResponseField>

    <ResponseField name="kind" type="string">
      One of `node`, `edge`, `setting`, `contact`, `knowledge`.
    </ResponseField>

    <ResponseField name="key" type="string">
      The node or edge ID, or the `settings`, `contact`, or `knowledge` field name.
    </ResponseField>

    <ResponseField name="path" type="string">
      Dot path to the conflicting value inside that unit. Empty string when the whole unit conflicts, such as one side deleting a node the other edited.
    </ResponseField>

    <ResponseField name="path_labels" type="array">
      Display labels aligned with `path`.
    </ResponseField>

    <ResponseField name="label" type="string">
      Human-readable name of the unit.
    </ResponseField>

    <ResponseField name="base" type="any">
      The value on the branch's base. Omitted when both sides added the value.
    </ResponseField>

    <ResponseField name="theirs" type="any">
      Dev's value. Omitted when dev deleted it.
    </ResponseField>

    <ResponseField name="ours" type="any">
      The branch's value. Omitted when the branch deleted it.
    </ResponseField>
  </Expandable>
</ResponseField>

<ResponseField name="errors" type="null | array">
  `null` on success, or a list of error objects if the request failed.
</ResponseField>

<ResponseExample>
  ```json Response theme={null}
  {
    "data": {
      "dev_head_version_id": "50dc2b1d-854f-4403-8c26-e845238cc03b",
      "up_to_date": false,
      "auto_merged": 1,
      "changes": [
        {
          "id": "node:40f4b50d-46a3-4235-99b7-09a299ce628c#data.rule",
          "kind": "node",
          "key": "40f4b50d-46a3-4235-99b7-09a299ce628c",
          "path": "data.rule",
          "path_labels": ["data", "rule"],
          "label": "Verify account",
          "base": "Ask for the account number and confirm the last four digits.",
          "theirs": "Ask for the account number, then confirm the last four digits and the billing zip code."
        }
      ],
      "conflicts": [
        {
          "id": "setting:systemPrompt",
          "kind": "setting",
          "key": "systemPrompt",
          "path": "",
          "path_labels": [],
          "label": "systemPrompt",
          "base": "You are the front desk assistant for Northwind Dental.",
          "theirs": "You are the front desk assistant for Northwind Dental. Keep answers under two sentences.",
          "ours": "You are the scheduling assistant for Northwind Dental. Always offer the next two open slots."
        }
      ]
    },
    "errors": null
  }
  ```

  ```json Up To Date theme={null}
  {
    "data": {
      "dev_head_version_id": "50dc2b1d-854f-4403-8c26-e845238cc03b",
      "up_to_date": true,
      "auto_merged": 0,
      "changes": [],
      "conflicts": []
    },
    "errors": null
  }
  ```

  ```json Not Found theme={null}
  {
    "data": null,
    "errors": [
      {
        "error": "NOT_FOUND",
        "message": "Agent or branch not found"
      }
    ]
  }
  ```
</ResponseExample>

***

Docs for agents: [llms.txt](/llms.txt)