## Attach a memory layer to a variation

`client.Agents.Variations.AddMemoryLayer(ctx, workspaceID, agentID, variationID, body) (*VariationMemoryLayerAssignment, error)`

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

Attaches a memory layer to a variation at a given position in the variation's baseline memory stack.

### Parameters

- `workspaceID string`

- `agentID string`

- `variationID string`

- `body AgentVariationAddMemoryLayerParams`

  - `MemoryLayerID param.Field[string]`

    Layer to attach. Accepts the canonical `memlyr_…` form or the `external_id:<value>` form.

  - `Position param.Field[int64]`

    Position in the stack. If omitted, server appends
    (max existing position + 1).

### Returns

- `type VariationMemoryLayerAssignment struct{…}`

  VariationMemoryLayerAssignment attaches a single MemoryLayer to a
  variation at a given position in the variation's baseline memory
  stack. A variation has at most one assignment per memory_layer_id.

  Variations only support whole-layer attachments — entry pinning is an
  objective-level capability.

  - `ID string`

    Assignment row id — handle for removing the assignment. Distinct
    from the referenced memory layer's id.

  - `MemoryLayer 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).

  - `Position int64`

    Position in the variation's baseline stack. Lower values sit lower;
    the highest-position assignment is on top of the variation's
    baseline. Gaps are fine — only relative position matters. Positions
    must be unique within a variation; a request that would collide
    with an existing assignment's position is rejected with
    InvalidArgument.

### 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"),
  )
  variationMemoryLayerAssignment, err := client.Agents.Variations.AddMemoryLayer(
    context.TODO(),
    "workspaceId",
    "agentId",
    "variationId",
    cadenya.AgentVariationAddMemoryLayerParams{

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

#### Response

```json
{
  "id": "id",
  "memoryLayer": {
    "id": "id",
    "name": "name"
  },
  "position": 0
}
```