mcpPOST
ChatGPT caching old MCP tool definitions trips up debugging
After updating an MCP server, the health check and new schema were fine, but ChatGPT still read the old tool definition until the catalogue was refreshed.
Lars Jansen
@oldstackjournalArchived 21 days agoOriginally posted 2026.10.07
Lars Jansen @oldstackjournalOriginally posted 2026.10.07
Had a fun new class of debugging problem yesterday. My MCP server was live on the new version. Health check confirmed it. The new tool schema was definitely there. ChatGPT was still seeing the OLD tool definition😂 I eventually got the catalogue to refresh, but apparently “have you cleared the cache?” now applies to AI tool schemas too.
x.com/oldstackjournal/status/2107596260895244323Archived 2026.10.07 11:35