> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agentvolumes.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Authentication required

> Stable Problem Details type URI page for authentication-required in the Agent Volumes v0.1 Registry API.

`https://agentvolumes.org/problems/authentication-required` identifies the `authentication-required` Problem Details type in the closed Agent Volumes v0.1 portable problem set.

| Field       | Value                                                       |
| ----------- | ----------------------------------------------------------- |
| Type URI    | `https://agentvolumes.org/problems/authentication-required` |
| Slug        | `authentication-required`                                   |
| HTTP status | `401`                                                       |
| Title       | `Authentication required`                                   |
| Meaning     | Bearer authentication is missing or invalid.                |

## Client guidance

Switch on the `type` URI when handling Agent Volumes Registry API errors. The human-readable `title` can vary by implementation or localization, but the `type` URI identifies the portable problem category.

## Canonical sources

* [Problem Details schema](/spec/0.1.0-rc.1/schemas/problem-details.schema.json)
* [Problem registry schema](/spec/0.1.0-rc.1/schemas/problem-registry.schema.json)
* [Problem registry fixture](https://github.com/agent-volumes/agent-volumes-spec/blob/release/0.1.0-rc1/conformance/fixtures/problem-registry.json)
* [API error table](/spec/0.1.0-rc.1/api/errors)