Cannot enable automatic marketplace sync: Claude GitHub App access error

Problem

In Claude's desktop plugin management UI, I can sync the blader/humanizer marketplace, but I cannot enable automatic sync. Enabling automatic sync displays a message saying that the Claude GitHub App needs access to this repository.

In the same UI, automatic sync can be enabled for ayghri/i-have-adhd.

Steps to reproduce

1. Add https://github.com/blader/humanizer as a marketplace in Claude.
2. Open Settings → Plugins → Manage marketplaces.
3. Confirm that Humanizer is shown as synced.
4. Attempt to enable automatic sync for Humanizer.

Actual behavior

Automatic sync cannot be enabled. The UI displays this message:

Auto-sync requires the Claude GitHub App to have access to this repository.

The message includes a "Grant access" button.

The marketplace is otherwise shown as synced at commit 8c307f3. The comparison marketplace, ayghri/i-have-adhd, is shown at 1ecea19 and allows automatic sync to be enabled.

Expected behavior

Automatic sync should be available for Humanizer if supported for this public marketplace. If it requires repository-owner setup or is subject to a Claude-side permission restriction, please document the prerequisite and the supported update workflow for users installing the upstream repository.

Separate manifest warning

Humanizer also displays “Synced with warnings” and this exact warning:

Plugin 'humanizer' has unrecognized key in plugin.json: '$schema' (stripped — the SDK ignores unknown top-level fields)

The sync details show 2026-10-17 12:43 and commit 8c307f3. The plugin manifest at that commit declares version 3.1.0.

This warning is already addressed by the open PR #307. I am referencing that PR rather than requesting another copy of the same fix. The warning is shown in the sync details; the GitHub App access error appears specifically when enabling automatic sync. I have not established a causal connection between them.

Investigation and open question

Both repositories use "source": "./" in their marketplace entries. I have not verified the Claude GitHub App installation or permissions on either upstream repository, so the successful comparison alone does not establish a packaging bug in Humanizer.

Could you check whether this repository needs any Claude GitHub App setup for automatic marketplace sync, or confirm whether this should be reported to Anthropic instead?

This report is based on the desktop UI behavior above, not a reproduction with the Claude Code CLI. The exact Claude app version has not been recorded.