MCP: content_create/content_update ignores taxonomies field (categories/tags not assigned)

[khoinguyenpham04]

This Roadmap discussion mirrors #953: MCP: content_create/content_update ignores taxonomies field (categories/tags not assigned).

Use this discussion to upvote the roadmap item and discuss priority, use cases, and product feedback. Keep implementation tracking, reproduction details, and PR-specific feedback on the source issue.

• Source issue: #953
• Status: Open
• Labels: roadmap/1.0, roadmap/api-mcp-agents
• Original author: Vallhalen

Original Issue

Problem

content_create and content_update MCP tools accept a taxonomies field without error, but do not persist taxonomy assignments (categories, tags) to the content item. The field is silently ignored.

This is a follow-up to #621, which was closed after SEO and bylines support was added to content_update. The taxonomy part of that issue was not resolved.

Steps to reproduce

// Create a post with taxonomies
await call('content_create', {
  collection: 'posts',
  slug: 'my-post',
  data: { title: 'Test Post', content: [...] },
  taxonomies: {
    category: ['porady'],        // slug
    tag: ['ai', 'seo'],          // slugs
  },
  status: 'draft',
});
// Result: post created, but NO taxonomies assigned

// Update existing post with taxonomies
await call('content_update', {
  collection: 'posts',
  id: 'POST_ID',
  taxonomies: {
    category: ['TERM_ID'],       // by ID
    tag: ['TERM_ID_1', 'TERM_ID_2'],
  },
});
// Result: returns OK, but NO taxonomies persisted

Verified via content_get - the returned item has no taxonomies field at all.

Expected behavior

content_create and content_update should persist taxonomy assignments, either by term slug or term ID.

Workaround

The REST API endpoint works correctly:

POST /_emdash/api/content/posts/{postId}/terms/{taxonomyName}
Body: { "termIds": ["TERM_ID_1", "TERM_ID_2"] }

This is undocumented but functional. I used it to bulk-assign categories and tags to 15 posts.

Additionally, content_get does not return taxonomy assignments in its response - you need to use GET /_emdash/api/content/posts/{postId}/terms/{taxonomyName} to check.

Environment

• EmDash 0.9.x (latest as of 2026-05-08)
• Cloudflare Workers deployment
• MCP server with content_create, content_update, taxonomy_list_terms tools

[danielmlr]

Source issue #953 was closed as completed by #1874 (in emdash 0.29.0). The 1.0 roadmap is tracked in #1873, so closing this mirror.