Connectors that come through your claude.ai account reach MCP servers (outside programs that give Claude Code extra tools). Claude Code can either use the older fixed way of talking to them or negotiate, meaning the two sides agree which version of the protocol to use. The fallback for this choice has moved from off to on, so these connections now negotiate automatically unless the server sends an explicit off, in which case they stay on the older way.
While negotiation is still in progress, only these messages may be sent: server/discover, initialize, notifications/initialized, ping, tools/list, tools/call, notifications/cancelled and notifications/roots/list_changed. Any other request fails with the stored error.
In the most recent reading, the flag server returned this setting on for this site's account and for an anonymous check, along with the matching setting for HTTP connections.
claude.ai connector servers will use the newer negotiation wherever the server does not override it, so their behaviour may differ from before.
tengu_mcp_protocol_negotiation_claudeai On for this account, and not off by defaultThe flag server returned on for the one account this site reads, and nothing in this release compiles it off by default. The compiled default is shown below, and says which it is when we cannot read one: a fifth of gates compile in a string or a number rather than on or off, and most published releases have no gate table behind them at all. No client can see what the server returns for your account.
This account: on · anonymous baseline: on · compiled default in v2.1.295: on
These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.
tengu_mcp_protocol_negotiation_http On for this account, and not off by defaultThe flag server returned on for the one account this site reads, and nothing in this release compiles it off by default. The compiled default is shown below, and says which it is when we cannot read one: a fifth of gates compile in a string or a number rather than on or off, and most published releases have no gate table behind them at all. No client can see what the server returns for your account.
This account: on · anonymous baseline: on · compiled default in v2.1.295: on
These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.
Read once, for one account on one subscription tier, against v2.1.295. It isn't a statement about your account. What a flag value here can and cannot tell you