## Retrieve a memory version

`beta.memory_stores.memory_versions.retrieve(memory_version_id, **kwargs) -> BetaManagedAgentsMemoryVersion`

**get** `/v1/memory_stores/{memory_store_id}/memory_versions/{memory_version_id}`

Retrieve a memory version

### Parameters

- `memory_store_id: String`

- `memory_version_id: String`

- `view: BetaManagedAgentsMemoryView`

  Query parameter for view

  - `:basic`

  - `:full`

- `betas: Array[AnthropicBeta]`

  Optional header to specify the beta version(s) you want to use.

  - `String = String`

  - `AnthropicBeta = :"message-batches-2024-09-24" | :"prompt-caching-2024-07-31" | :"computer-use-2024-10-22" | 25 more`

    - `:"message-batches-2024-09-24"`

    - `:"prompt-caching-2024-07-31"`

    - `:"computer-use-2024-10-22"`

    - `:"computer-use-2025-01-24"`

    - `:"pdfs-2024-09-25"`

    - `:"token-counting-2024-11-01"`

    - `:"token-efficient-tools-2025-02-19"`

    - `:"output-128k-2025-02-19"`

    - `:"files-api-2025-04-14"`

    - `:"mcp-client-2025-04-04"`

    - `:"mcp-client-2025-11-20"`

    - `:"dev-full-thinking-2025-05-14"`

    - `:"interleaved-thinking-2025-05-14"`

    - `:"code-execution-2025-05-22"`

    - `:"extended-cache-ttl-2025-04-11"`

    - `:"context-1m-2025-08-07"`

    - `:"context-management-2025-06-27"`

    - `:"model-context-window-exceeded-2025-08-26"`

    - `:"skills-2025-10-02"`

    - `:"fast-mode-2026-02-01"`

    - `:"output-300k-2026-03-24"`

    - `:"user-profiles-2026-03-24"`

    - `:"advisor-tool-2026-03-01"`

    - `:"managed-agents-2026-04-01"`

    - `:"cache-diagnosis-2026-04-07"`

    - `:"thinking-token-count-2026-05-13"`

    - `:"server-side-fallback-2026-06-01"`

    - `:"fallback-credit-2026-06-01"`

### Returns

- `class BetaManagedAgentsMemoryVersion`

  A `memory_version` object: one immutable, attributed row in a memory's append-only history. Every non-no-op mutation to a memory produces a new version. Versions belong to the store (not the individual memory) and persist after the memory is deleted. Retrieving a redacted version returns 200 with `content`, `path`, `content_size_bytes`, and `content_sha256` set to `null`; branch on `redacted_at`, not HTTP status.

  - `id: String`

    Unique identifier for this version (a `memver_...` value).

  - `created_at: Time`

    A timestamp in RFC 3339 format

  - `memory_id: String`

    ID of the memory this version snapshots (a `mem_...` value). Remains valid after the memory is deleted; pass it as `memory_id` to [List memory versions](/docs/en/api/beta/memory_stores/memory_versions/list) to retrieve the full lineage including the `deleted` row.

  - `memory_store_id: String`

    ID of the memory store this version belongs to (a `memstore_...` value).

  - `operation: BetaManagedAgentsMemoryVersionOperation`

    The kind of mutation a `memory_version` records. Every non-no-op mutation to a memory appends exactly one version row with one of these values.

    - `:created`

    - `:modified`

    - `:deleted`

  - `type: :memory_version`

    - `:memory_version`

  - `content: String`

    The memory's UTF-8 text content as of this version. `null` when `view=basic`, when `operation` is `deleted`, or when `redacted_at` is set.

  - `content_sha256: String`

    Lowercase hex SHA-256 digest of `content` as of this version (64 characters). `null` when `redacted_at` is set or `operation` is `deleted`. Populated regardless of `view` otherwise.

  - `content_size_bytes: Integer`

    Size of `content` in bytes as of this version. `null` when `redacted_at` is set or `operation` is `deleted`. Populated regardless of `view` otherwise.

  - `created_by: BetaManagedAgentsActor`

    Identifies who performed a write or redact operation. Captured at write time on the `memory_version` row. The API key that created a session is not recorded on agent writes; attribution answers who made the write, not who is ultimately responsible. Look up session provenance separately via the [Sessions API](/docs/en/api/sessions-retrieve).

    - `class BetaManagedAgentsSessionActor`

      Attribution for a write made by an agent during a session, through the mounted filesystem at `/mnt/memory/`.

      - `session_id: String`

        ID of the session that performed the write (a `sesn_...` value). Look up the session via [Retrieve a session](/docs/en/api/sessions-retrieve) for further provenance.

      - `type: :session_actor`

        - `:session_actor`

    - `class BetaManagedAgentsAPIActor`

      Attribution for a write made directly via the public API (outside of any session).

      - `api_key_id: String`

        ID of the API key that performed the write. This identifies the key, not the secret.

      - `type: :api_actor`

        - `:api_actor`

    - `class BetaManagedAgentsUserActor`

      Attribution for a write made by a human user through the Anthropic Console.

      - `type: :user_actor`

        - `:user_actor`

      - `user_id: String`

        ID of the user who performed the write (a `user_...` value).

  - `path: String`

    The memory's path at the time of this write. `null` if and only if `redacted_at` is set.

  - `redacted_at: Time`

    A timestamp in RFC 3339 format

  - `redacted_by: BetaManagedAgentsActor`

    Identifies who performed a write or redact operation. Captured at write time on the `memory_version` row. The API key that created a session is not recorded on agent writes; attribution answers who made the write, not who is ultimately responsible. Look up session provenance separately via the [Sessions API](/docs/en/api/sessions-retrieve).

### Example

```ruby
require "anthropic"

anthropic = Anthropic::Client.new(api_key: "my-anthropic-api-key")

beta_managed_agents_memory_version = anthropic.beta.memory_stores.memory_versions.retrieve(
  "memory_version_id",
  memory_store_id: "memory_store_id"
)

puts(beta_managed_agents_memory_version)
```

#### Response

```json
{
  "id": "id",
  "created_at": "2019-12-27T18:11:19.117Z",
  "memory_id": "memory_id",
  "memory_store_id": "memory_store_id",
  "operation": "created",
  "type": "memory_version",
  "content": "content",
  "content_sha256": "content_sha256",
  "content_size_bytes": 0,
  "created_by": {
    "session_id": "x",
    "type": "session_actor"
  },
  "path": "path",
  "redacted_at": "2019-12-27T18:11:19.117Z",
  "redacted_by": {
    "session_id": "x",
    "type": "session_actor"
  }
}
```
