You'll noticeTier: how much it should matter to you
1Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
MCPArea: what it touches
ImprovementsKind: in v2.1.315,
ImprovementsSection of the release
What
MCP servers are add-ons that give Claude extra tools. Connections to them are encrypted with TLS. CA certificates are the authorities trusted to vouch that a server is genuine.
The code that sends requests to MCP servers was rewritten for hosted_worker mode. It now compares the request's list of trusted CA certificates with the list Claude Code is using now:
If the two lists have nothing in common, the request is not sent. Instead there is an error, "MCP request not sent: its list of trusted CA certificates has nothing in common with the one Claude Code uses now", which tells you to reconnect the server.
If they share some certificates, the request is narrowed to the shared ones.
Why
This only affects hosted workers whose TLS settings change during a session. When the trusted certificates no longer overlap, you get an error straight away that tells you to reconnect the server.
