---
# @generated by sylphx-gen 0.1.0 from contracts@e145cc7cf1bc9605f2b27439e5e17ed76a1a2fd7e7021906a013f7565e4a0cd5. Do not edit.
title: "Update a build cache"
description: "`build.build_caches.update` (PATCH /v1/{build_cache.name}): Updates a build cache."
type: reference
product: builds
summary: "Updates a build cache."
updated: 2026-09-28
nav: false
---

> **This method is not served on the public API.** `api.sylphx.com` does not route this call: its backend is not deployed behind the public API, or does not implement the call. This page documents the contract. It is kept out of the sidebar and of search engines.

Updates a build cache.

**Not available yet.** Sylphx Build is declared in the registry but no backend serves it: every call answers `501` with the problem code `UNIMPLEMENTED`.

- **Path** `PATCH https://api.sylphx.com/v1/orgs/acme/projects/shop/build_caches/build-cache`
- **Scope** `build:write`
- **Effect** `write` — a successful call changes state.
- **Collection** [build_caches](/docs/api/build_caches)
- **Query** `update_mask`, `allow_missing`, `validate_only`

## Request

| Field | Type | What it is |
| --- | --- | --- |
| `build_cache` | `BuildCache` | The build cache to update; `name` identifies it. Required. |
| `update_mask` | `field_mask` | The fields to write; unset writes every populated field. |
| `allow_missing` | `bool` | Create the Resource when it does not exist (declarative upsert). |
| `validate_only` | `bool` | Validate and return the result without writing anything. |

### BuildCache

| Field | Type | What it is |
| --- | --- | --- |
| `name` | `string` | `orgs/{org}/projects/{project}/build_caches/{build_cache}`. |
| `meta` | `ResourceMeta` | Resource metadata. |
| `spec` | `BuildCacheSpec` | Desired state. Required. |

### ResourceMeta

| Field | Type | What it is |
| --- | --- | --- |
| `labels` | `map<string, string>` | Caller-writable, indexed labels (AIP-122 label rules). |
| `annotations` | `map<string, string>` | Caller-writable, unindexed annotations. |
| `display_name` | `string` | Caller-writable human-readable name. |

### BuildCacheSpec

| Field | Type | What it is |
| --- | --- | --- |
| `retention` | `duration` | Entries unused this long are evicted; default 7 days. |

## Response

| Field | Type | What it is |
| --- | --- | --- |
| `name` | `string` | `orgs/{org}/projects/{project}/build_caches/{build_cache}`. |
| `uid` | `string` | `bch_<cell><ulid>`; never reused. Output only. |
| `meta` | `ResourceMeta` | Resource metadata. |
| `spec` | `BuildCacheSpec` | Desired state. Required. |
| `status` | `BuildCacheStatus` | Observed state. Output only. |

### ResourceMeta

| Field | Type | What it is |
| --- | --- | --- |
| `generation` | `int64` | Increases by one on every change to `spec`. Output only. |
| `etag` | `string` | Strong ETag (AIP-154): changes on any change to spec, status, or metadata. Send it back as `If-Match` or `etag` to make Update and Delete conditional; a mismatch fails with ABORTED / 409 `ETAG_MISMATCH`. Output only. |
| `create_time` | `timestamp` | When the Resource was created. Output only. |
| `update_time` | `timestamp` | When the Resource last changed. Output only. |
| `delete_time` | `timestamp` | Set while the Resource is being deleted. Output only. |
| `labels` | `map<string, string>` | Caller-writable, indexed labels (AIP-122 label rules). |
| `annotations` | `map<string, string>` | Caller-writable, unindexed annotations. |
| `display_name` | `string` | Caller-writable human-readable name. |
| `creator` | `string` | The principal that created the Resource. Output only. |

### BuildCacheSpec

| Field | Type | What it is |
| --- | --- | --- |
| `retention` | `duration` | Entries unused this long are evicted; default 7 days. |

### BuildCacheStatus

| Field | Type | What it is |
| --- | --- | --- |
| `observed_generation` | `int64` | The generation this status was computed from. Output only. |
| `conditions` | `Condition[]` | Ready, Reconciling, Stalled. Output only. |
| `size_bytes` | `int64` | Bytes stored. Output only. |
| `last_use_time` | `timestamp` | When a build last read the cache. Output only. |

### Condition

| Field | Type | What it is |
| --- | --- | --- |
| `type` | `string` | The condition type, for example `Ready`. |
| `status` | `ConditionStatus` | Whether the condition holds. One of `true`, `false`, `unknown`. |
| `observed_generation` | `int64` | The generation this observation was made against. |
| `reason` | `string` | A machine-readable UpperCamelCase reason. |
| `message` | `string` | A customer-safe human-readable message. |
| `severity` | `Severity` | How severe a FALSE condition is. One of `info`, `warning`, `error`. |
| `transition_time` | `timestamp` | When `status` last changed. |

## Errors

- [`UNAUTHENTICATED`](/docs/api/errors/UNAUTHENTICATED) — No valid key or token was presented.
- [`PERMISSION_DENIED`](/docs/api/errors/PERMISSION_DENIED) — The key lacks the method's permission.
- [`RESOURCE_NOT_FOUND`](/docs/api/errors/RESOURCE_NOT_FOUND) — The named Resource does not exist or is not visible.
- [`UNKNOWN_FIELD`](/docs/api/errors/UNKNOWN_FIELD) — The request has a field the schema does not know.
- [`INVALID_FIELD`](/docs/api/errors/INVALID_FIELD) — A field failed validation.
- [`ETAG_MISMATCH`](/docs/api/errors/ETAG_MISMATCH) — The etag sent does not match the Resource's current etag.
- [`IDEMPOTENCY_KEY_REUSED`](/docs/api/errors/IDEMPOTENCY_KEY_REUSED) — An Idempotency-Key was reused with another body.
- [`IDEMPOTENCY_IN_PROGRESS`](/docs/api/errors/IDEMPOTENCY_IN_PROGRESS) — The first call with this Idempotency-Key is still running.

Every error arrives in the body [Errors](/docs/platform/errors) describes.

## Examples

**cURL**

```curl
curl -X PATCH "https://api.sylphx.com/v1/orgs/acme/projects/shop/build_caches/build-cache" \
  -H "Authorization: Bearer $SYLPHX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"name":"orgs/acme/projects/shop/build_caches/build-cache","spec":{}}'
```

**TypeScript**

```ts
const response = await sylphx.build.buildCaches.update({ buildCache: { name: 'orgs/acme/projects/shop/build_caches/build-cache', spec: {} } })
```

**Rust**

```rust
let mut req = sylphx::build::UpdateBuildCacheRequest::default();
req.build_cache = Some(sylphx::build::BuildCache {
    name: "orgs/acme/projects/shop/build_caches/build-cache".to_string(),
    spec: Some(Default::default()),
    ..Default::default()
});
let response = sx.build().build_caches().update(req).await?;
```

**CLI**

```bash
sylphx build build-caches update orgs/acme/projects/shop/build_caches/build-cache
```

**MCP**

```json
{ "method_id": "build.build_caches.update", "args": {"build_cache":{"name":"orgs/acme/projects/shop/build_caches/build-cache","spec":{}}} }
```