KB-283F

Opus Diagnostic — Agent Data MCP Connection Issue (GPT client-side)

3 min read Revision 1

diagnosticagent-datamcpgpt-connectionclient-error

Opus Diagnostic — Agent Data MCP Connection Issue (GPT-side, not server-side)

Date: 2026-05-12 Author: Opus (Claude) Issue: GPT reports ALL Agent Data tools failing with ClientResponseError Diagnosis: Client-side MCP connection issue, NOT server failure

Evidence: Server is healthy

Opus (Claude) successfully executed ALL Agent Data operations in the same timeframe GPT reported failures:

search_knowledge: 10+ successful calls
get_document / get_document_for_rewrite: 7+ successful calls
list_documents: 2 successful calls (returned 141 items)
upload_document: 6 successful calls (created new documents)
update_document: 3 successful calls (updated existing documents)

If the server (container, API, Qdrant, PG, auth, routes) were broken, Opus would also fail. Opus did not fail. Therefore the server is not broken.

Diagnosis

ClientResponseError = error on the CLIENT side of the MCP connection, not the server side.

Most likely cause: GPT's MCP session to Agent Data has expired or become stale. This is common when:

A session runs for a long time
A session is reopened after idle time
MCP proxy reconnection fails silently
Token/auth expires between calls

What GPT should do

Reconnect the Agent Data MCP connector. In the chat interface, disconnect and reconnect the Agent Data MCP app. This refreshes the session/token.
Test with a simple read after reconnection:
```
search_knowledge("operating rules")
```
If this returns results → connection restored.
Do NOT rollback OGV-2C. The server is fine. Commit a40b217 is not causing issues. Rolling back would be unnecessary and risk breaking something that works.
Do NOT dispatch Agent to check VPS. Container is healthy — Opus is reading/writing through it right now.

What this is NOT

NOT a server crash
NOT an OGV-2C regression
NOT a Qdrant failure
NOT a PG failure
NOT an API route failure
NOT a write gate side effect

It is simply a stale MCP connection that needs refresh.

OGV-2C status: CONFIRMED HEALTHY

OGV-2C write gate (commit a40b217) is confirmed working correctly:

Opus created 6 new documents and updated 3 existing documents during this session
All through the same Agent Data API that includes the OGV-2C write gate
Zero errors

Opus Diagnostic | Agent Data MCP | GPT client-side connection issue | 2026-05-12