## Add an assignment to a variation

`client.Agents.Variations.AddAssignment(ctx, workspaceID, agentID, variationID, body) (*VariationAssignment, error)`

**post** `/v1/workspaces/{workspaceId}/agents/{agentId}/variations/{variationId}/assignments`

Assigns a tool, tool set, or sub-agent to a variation. Exactly one target ID must be set.

### Parameters

- `workspaceID string`

- `agentID string`

- `variationID string`

- `body AgentVariationAddAssignmentParams`

  - `SubAgentID param.Field[string]`

  - `ToolID param.Field[string]`

  - `ToolSetID param.Field[string]`

### Returns

- `type VariationAssignment struct{…}`

  A read-only reference to a single tool, tool set, or sub-agent attached to
  a variation. Read the full set of assignments via `AgentVariationInfo.assignments`;
  mutations go through the dedicated add/remove assignment endpoints.

  The `id` identifies the assignment itself (not the referenced resource) and
  is the handle used to remove the assignment. It is returned by the add
  endpoint and present on every entry in `AgentVariationInfo.assignments`.

  - `ID string`

  - `Agent BareMetadata`

    BareMetadata contains the minimal metadata for a resource: the ID and an
    optional human-readable name. These are used for reference fields where the
    full metadata (account scoping, timestamps, labels, external IDs) is not
    needed — e.g., the tool references inside an agent variation spec or the
    tools assigned to an objective. Both fields are server-populated; clients
    provide IDs through sibling fields rather than by constructing a
    BareMetadata themselves.

    - `ID string`

    - `Name string`

      Human-readable name of the referenced resource, populated by the server
      on reads for convenience. Absent on references to resources that do not
      have a name (e.g., objective tasks).

  - `Tool BareMetadata`

    BareMetadata contains the minimal metadata for a resource: the ID and an
    optional human-readable name. These are used for reference fields where the
    full metadata (account scoping, timestamps, labels, external IDs) is not
    needed — e.g., the tool references inside an agent variation spec or the
    tools assigned to an objective. Both fields are server-populated; clients
    provide IDs through sibling fields rather than by constructing a
    BareMetadata themselves.

  - `ToolSet BareMetadata`

    BareMetadata contains the minimal metadata for a resource: the ID and an
    optional human-readable name. These are used for reference fields where the
    full metadata (account scoping, timestamps, labels, external IDs) is not
    needed — e.g., the tool references inside an agent variation spec or the
    tools assigned to an objective. Both fields are server-populated; clients
    provide IDs through sibling fields rather than by constructing a
    BareMetadata themselves.

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/cadenya/cadenya-go"
  "github.com/cadenya/cadenya-go/option"
)

func main() {
  client := cadenya.NewClient(
    option.WithAPIKey("My API Key"),
  )
  variationAssignment, err := client.Agents.Variations.AddAssignment(
    context.TODO(),
    "workspaceId",
    "agentId",
    "variationId",
    cadenya.AgentVariationAddAssignmentParams{

    },
  )
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", variationAssignment.ID)
}
```

#### Response

```json
{
  "id": "id",
  "agent": {
    "id": "id",
    "name": "name"
  },
  "tool": {
    "id": "id",
    "name": "name"
  },
  "toolSet": {
    "id": "id",
    "name": "name"
  }
}
```