---
title: "Fetch human public-evidence representation headers."
method: HEAD
path: "/evidence/artifacts/{artifactId}"
tags: ["Run Cards"]
---

# Fetch human public-evidence representation headers.

`HEAD /evidence/artifacts/{artifactId}`

## Request

- Base URL: `https://huggingbay.xyz`
- URL: `https://huggingbay.xyz/evidence/artifacts/{artifactId}`
- Auth: none declared

Public, read-only projection of existing server-owned Run Card, accepted-run proof, rescue, request, and agent-action authorities. The default representation is html; format or Accept negotiation can select any declared representation. Every representation is derived from one recorded projection, preserves evidence digests, freshness and uncertainty, and fails closed without inferring throughput, compatibility, success, geography, or license safety.

**Inputs.** Path, query and header fields are listed below. No request body is required.

**Outputs.** See each status below for its media type, schema and headers. A missing record or unavailable capability is not a successful empty result.

**Errors.** HEAD returns headers without a body. Use the HTTP status and Retry-After.

**Rate limits.** Public read budgets apply by client IP and route group. This operation can have a smaller route-specific budget. Read Retry-After on 429 or retryable 503 responses.

**Example setup.** Use an identifier returned by the matching list, search or create operation. Sample identifiers are not a promise that a record exists.

## Path parameters

- `artifactId` string, required

## Query parameters

- `format` 'html' | 'json' | 'jsonld' | 'mcp' | 'citation' | 'markdown' | 'share' | 'badge'

## Response `200`

Representation headers only; no response body.

## Other responses

- `304`: The selected representation matches If-None-Match.
- `404`: The route identifier is malformed, sensitive-looking, or unavailable for public projection.
- `405`: Method not allowed; public evidence is GET/HEAD only.
- `406`: The requested representation format is unsupported.
- `422`: Unknown, duplicate, or otherwise invalid query parameters.
- `429`: Public read rate limit exceeded.
- `503`: A bounded authority read failed closed, admission capacity was reserved, or the selected representation exceeded its response limit.

---

[API](https://skmtc.dev/huggingbay/apis/hugging-bay-public-api.md) · [All operations](https://skmtc.dev/huggingbay/apis/hugging-bay-public-api/llms.txt) · [OpenAPI document](https://skmtc.dev/huggingbay/apis/hugging-bay-public-api/revisions/ea7ba26b1e27?raw)