UNRESOLVED_MCP_SERVER

const UNRESOLVED_MCP_SERVER: "" = ''

Defined in: _worktrees/docs-release/gaunt-sloth/packages/core/src/core/approvals/mcpSubjects.ts:53

The server identity an MCP tool call gets when its name does not resolve to exactly one configured mcpServers key — nothing matched, or two nested keys both did.

The empty string, and that is load-bearing rather than arbitrary. A server key is z.string().min(1) both under approvals.mcp.servers (§9) and on an mcpTool rule entry (§3.1), so this value is the one identity a user cannot spell in config: no entry can name it. An unresolvable call is therefore matchable only by the reserved server: "*" (which means every server and is correct here).

Being unspellable is what makes it unnameable; it is not by itself what makes it untrusted, because a lookup that misses under servers falls through to approvals.mcp.defaults. That second half is enforced in trustedAnnotationHints, which refuses this value outright, and in mcpDeclaredAnnotationLookup, which will not look a declaration up under it. Both are required: the first stops a permissive defaults reaching an unattributable call, the second stops one being found by string arithmetic on the sentinel.