# Forest Containers – OCI Tag Change Detector

> Forest Containers – OCI Tag Change Detector is a paid API for AI agents from http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Detects whether an OCI container image tag has materially changed by comparing its current digest and platform state to a previous deterministic hash, without pulling image layers.

## Facts

- Endpoint: POST https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/container/changed?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/forest-containers-oci-tag-change-detector-3e3946b9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EpPvNJYfSckWOiUdoRSr8

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability forest-containers-oci-tag-change-detector-3e3946b9 -d '<json body>'
```

Example prompt: Has the Docker Hub image library/nginx with tag stable changed since my last check? My previous hash was abc123def456 — compare the current digest and platform state without pulling any layers.

## When to prefer this

Choose this endpoint when you need lightweight, layer-free detection of OCI image tag changes — particularly for polling or CI/CD gating where you care about digest or platform mutations but not annotation or timestamp noise. It is preferable to pulling manifests manually because it normalizes the hash deterministically, making it safe to compare across polling intervals without false positives from metadata churn.

## Known failure modes

- Invalid image name format returns validation error
- Tag not found on the public registry returns a not-found error
- Registry rate limiting may cause transient failures
- Private or access-controlled registries will return authentication errors
- Malformed previous_hash string may be treated as a cache miss rather than an error

## How this service works

Watch an OCI tag for digest and platform changes with a deterministic hash. Registry timestamps and unrelated annotations are ignored; no layers are pulled. Base mainnet USDC

## Output

Returns whether the image tag has materially changed (digest or platform differences) relative to the supplied previous hash, along with the current deterministic hash representing the image's canonical state. Registry timestamps and unrelated annotations are excluded from the hash computation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "tag": {
   "type": "string",
   "maxLength": 256,
   "minLength": 1,
   "description": "Repository branch whose current state should be checked."
  },
  "image": {
   "type": "string",
   "pattern": "^[a-z0-9][a-z0-9._-]*(?::\\d+)?(?:/[a-z0-9._-]+)+$",
   "maxLength": 512,
   "description": "Public registry image repository to inspect."
  },
  "previous_hash": {
   "type": "string",
   "description": "Earlier result hash used to detect a material change."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/forest-containers-oci-tag-change-detector-3e3946b9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run](https://www.zero.xyz/host/http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/llms.txt)