What probably matters to youSection of the release
What
The system/init SDK message now carries mcp_server_errors, so a programmatic caller can see which MCP config entries were rejected at validation time rather than silently getting fewer servers.
Details
each element is {name, type, message} for a config entry that failed validation and was skipped
entries whose server did connect anyway are filtered out of the array
the MCP config loader tags validation failures with a stable code, adding "invalid_config" alongside the existing categories
the schema note says the key is omitted when empty, and that "CI can fail on (mcp_server_errors?.length ?? 0) > 0"
the REPL bridge currently passes an empty list, so this is populated on the SDK path only
Evidence
mcp_server_errors
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Read from
Names in the bundlemcp_server_errors
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeAdded mcp_server_errors to the headless stream-json init event, listing --mcp-config entries skipped by config validation; terminal runs…
