Conformance witness · observation, not accusation · recomputable

Tool-surface change observed — api.xdata.kr

Endpoint: https://api.xdata.kr/mcp

Version string served, unchanged across both observations: 1.0.0

Change first observed: 2026-10-10T19:40:03.823Z

Finding: CLASS_SUSPENDED_CRITICAL

Surface expanded without a version change, and at least one new tool takes an action (writes, sends, moves money, or deletes).

What we observed

Two anonymous tools/list enumerations of the endpoint above, at different times.

The serverInfo.version string was byte-identical in both. The tool set was not.

Tools present in the later enumeration but not the earlier (129):

Why this may matter to your users

A client that pinned 1.0.0 and reviewed the tool list at

pin time is, today, being served a different list under the same version string. Gateways

and MCP hosts that cache an approved tool set per version will not re-request approval,

because from their side nothing announced a change.

In this case 29 of the new tools take an action rather than returning data (fourinsure__b1__workplace__auto_transfer_unagreement__init, google__ads__demand_gen__campaign__create, google__ads__demand_gen__campaign__update, google__ads__display__campaign__create, google__ads__display__campaign__update, google__ads__pmax__campaign__create, google__ads__pmax__campaign__update, google__ads__search__campaign__create, google__ads__search__campaign__update, google__ads__video__asset__create, google__analytics__measurement__create, google__analytics__measurement__update, google__search_console__site__remove, google__search_console__sitemap__delete, google__tag_manager__tag__create, google__tag_manager__tag__update, google__tag_manager__version__publish, google__youtube__playlist__create, google__youtube__report_job__create, google__youtube__video__update, hometax__cash_receipt__daily_issue__cancel, hometax__cash_receipt__daily_issue__modify, nhis_edi__certificates__health_premium_payment__individual__init, nhis_edi__certificates__payment_completion__init, nhis_edi__certificates__payment_completion__issue, nps_edi__b1__national_pension_premiums__payment_history, wetax__tax__local_income__special_withholding__cancel, wetax__tax__local_income__special_withholding__payment_status, work24__subsidy__application__attachment_delete),

so the difference between the approved set and the served set is not only informational.

Verify this yourself

This is a plain MCP handshake. No credentials, nothing of ours required:

curl -s -X POST 'https://api.xdata.kr/mcp' \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -H 'MCP-Protocol-Version: 2025-06-18' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"check","version":"1"}}}'
# then, with the returned Mcp-Session-Id:
curl -s -X POST 'https://api.xdata.kr/mcp' \
  -H 'Content-Type: application/json' -H 'Accept: application/json, text/event-stream' \
  -H 'MCP-Protocol-Version: 2025-06-18' -H 'Mcp-Session-Id: <id>' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}'

Our surface hashes over the sorted tool names plus sorted input-schema property names:

observationsurface hash
earlier8dd63bc837c73917c532c5807c74b8c38eb958c3a0227806dd22357e74749b67
later64284fd8d9c0592b63a35bf7cf9503097fecae6e99a95d87b84083d6c342bf0e

If your own enumeration disagrees with the later hash, we are wrong and we want to hear it.

What this report does NOT say

deploy produces exactly this signal, and that is the most likely explanation.

under an unchanged version string.

Absence from our view is not absence from your server.

Method

Unannounced periodic re-enumeration of a live MCP population — we ask the endpoint

directly on a schedule rather than waiting to be notified. Relevant because only

6.4% of live MCP servers have a working channel to announce a change at all

(69.1% never declare tools.listChanged; of those that do, most expose no

server-initiated stream to send it on). A change like the one above cannot reach a

notification-based monitor, which is why it is normally invisible.

*StillOS Digital Holdings — continuous conformance witness for MCP servers.*

*Report generated 2026-10-30T17:18:49.826Z from observations dated 2026-10-10T19:40:03.823Z.*

Is this your server?

If anything here is wrong — a change you did not make, a hash that does not match, a host that was reassigned to you — tell us and we will correct or remove this page. No proof required to request removal; the record is whatever we observed, and your word about your own host outranks it.

Free. Goes to a human. Or email stillmarcus24@gmail.com.