multi_select write rejects valid tag returned by list_tags for custom property

Have you read a contributing guide?

• I have read CONTRIBUTING.md
• I have searched the existing issues and didn't find any that were similar
• I have considered creating a pull request with fixes instead of a bug report and want to proceed

Current Behavior

When updating an object and assigning a value to a custom multi_select property, the API rejects the option as invalid, even though the same
option is returned by list_tags for that exact property.

I tested both:

• the tag id
• the tag key

Both are rejected.

Error returned by update-object:

   {
    "status": 400,
    "object": "error",
    "code": "bad_request",
    "message": "bad input: invalid multi_select option for \"genero\": bafyreibv3xab76u37lhzr7il2vm2li226jq3ywfkfxum3fvqstngk4s3ke"
  }

Additional Context

This looks like a read/write inconsistency:

• list_tags says the tag belongs to the property
• update-object rejects the same tag for that property

I also noticed duplicate-looking entries in this property's tag list, for example two separate tags with key/name related to novela, which may
indicate an internal indexing or metadata inconsistency for custom multi-select properties.

Documentation References

• Changelog: https://developers.anytype.io/docs/reference/changelog/
• List tags: https://developers.anytype.io/docs/reference/2025-11-08/list-tags/
• Current behavior documented for multi_select: accepts tag keys or IDs

Expected Behavior

If list_tags returns a tag as belonging to property genero, that tag should be accepted by object create/update requests for that property.

According to the current API documentation, multi_select should accept tag keys or tag IDs.

Steps To Reproduce

1. Use a space with a custom multi_select property named genero
2. Call list_tags for that property
3. Take one returned tag from the response
4. Try to update an object with that tag as the value for genero

Reproduction Data

Space

  {
    "space_id": "bafyreih3tia7jxd6who2tqczxxrqy7wupxr2buk33edhsyrrzjakaxqlaa.9ldhqwv21s5z"
  }

Property

  {
    "property_id": "bafyreih7scpbieixek72dtd763glky2665ezu4v6jo3eqt5h62tnycnneu",
    "property_key": "genero"
  }

Object being updated

  {
    "object_id": "bafyreicj7mcbphf52wpfiu5f7oh4jex6daosfll6jxi3tupfmiujldfrny"
  }

list_tags request

  {
    "property_id": "bafyreih7scpbieixek72dtd763glky2665ezu4v6jo3eqt5h62tnycnneu",
    "space_id": "bafyreih3tia7jxd6who2tqczxxrqy7wupxr2buk33edhsyrrzjakaxqlaa.9ldhqwv21s5z"
  }

list_tags response except

  {
    "data": [
      {
        "object": "tag",
        "id": "bafyreibv3xab76u37lhzr7il2vm2li226jq3ywfkfxum3fvqstngk4s3ke",
        "key": "clasico",
        "name": "Clásico",
        "color": "purple"
      }
    ]
  }

Update request using tag ID

  {
    "object_id": "bafyreicj7mcbphf52wpfiu5f7oh4jex6daosfll6jxi3tupfmiujldfrny",
    "space_id": "bafyreih3tia7jxd6who2tqczxxrqy7wupxr2buk33edhsyrrzjakaxqlaa.9ldhqwv21s5z",
    "properties": [
      {
        "key": "genero",
        "multi_select": [
          "bafyreibv3xab76u37lhzr7il2vm2li226jq3ywfkfxum3fvqstngk4s3ke"
        ]
      }
    ]
  }

Update request using tag key

  {
    "object_id": "bafyreicj7mcbphf52wpfiu5f7oh4jex6daosfll6jxi3tupfmiujldfrny",
    "space_id": "bafyreih3tia7jxd6who2tqczxxrqy7wupxr2buk33edhsyrrzjakaxqlaa.9ldhqwv21s5z",
    "properties": [
      {
        "key": "genero",
        "multi_select": [
          "clasico"
        ]
      }
    ]
  }

Both requests fail with a validation error saying the multi_select option is invalid.

Environment

- OS: Debian
- Version: 13

Anything else?

No response

Start by reproducing the mismatch through the list_tags and update-object API entry points using the supplied property, object, and tag data. Trace where multi_select values are resolved and validated, then verify that a tag returned by list_tags is accepted by both ID and key; add or run the relevant API validation tests if present.