# MCP Issues with Claude Cowork

**URL:** <https://discourse.devontechnologies.com/t/mcp-issues-with-claude-cowork/87003>\
**Category:** Artificial Intelligence\
**Created:** [May 25, 2026, 8:43pm UTC](https://discourse.devontechnologies.com/t/mcp-issues-with-claude-cowork/87003 "2026-05-25T20:43:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![BurtonHable](https://discourse.devontechnologies.com/user_avatar/discourse.devontechnologies.com/burtonhable/32/26243_2.png) [@BurtonHable](https://discourse.devontechnologies.com/u/BurtonHable)\
**Post date:** [May 25, 2026, 8:43pm UTC](https://discourse.devontechnologies.com/t/mcp-issues-with-claude-cowork/87003/1 "2026-05-25T20:43:32Z")

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Hello all! I was trying to do some cleanup of my custom metadata using the new MCP and Claude Cowork. Two issues I ran into:

First, `get_record_custom_metadata` throws `Invalid type in JSON write (__NSCFData)` on any record with a populated `richtext`-type custom metadata field.

Second, `resolve_google_books_metadata` consistently returns HTTP 429 (Too Many Requests) on the first call, before any repeated requests have been made.

Any thoughts on what to do?

Thanks in advance! ~Burton

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**Author:** ![BLUEFROG](https://discourse.devontechnologies.com/user_avatar/discourse.devontechnologies.com/bluefrog/32/135_2.png) [@BLUEFROG](https://discourse.devontechnologies.com/u/BLUEFROG)\
**Post date:** [May 25, 2026, 8:55pm UTC](https://discourse.devontechnologies.com/t/mcp-issues-with-claude-cowork/87003/2 "2026-05-25T20:55:04Z")

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Welcome @BurtonHable  
In DEVONthink, hold the _Option_ key and choose _Help \> Report Bug_ to start a support ticket. We can look at the logs and information there.

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**Author:** ![cgrunenberg](https://discourse.devontechnologies.com/user_avatar/discourse.devontechnologies.com/cgrunenberg/32/7172_2.png) [@cgrunenberg](https://discourse.devontechnologies.com/u/cgrunenberg)\
**Post date:** [May 26, 2026, 6:10am UTC](https://discourse.devontechnologies.com/t/mcp-issues-with-claude-cowork/87003/3 "2026-05-26T06:10:47Z")

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> [@BurtonHable](#):
>
> First, `get_record_custom_metadata` throws `Invalid type in JSON write (__NSCFData)` on any record with a populated `richtext`-type custom metadata field.

This is a known issue and already fixed for the next release.

> [@](#):
>
> Second, `resolve_google_books_metadata` consistently returns HTTP 429 (Too Many Requests) on the first call, before any repeated requests have been made.

We’ll check this.