Under the hoodTier: how much it should matter to you
3Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
Tool ResultsArea: what it touches
Internal ChangesKind: in v2.1.275,
Internal ChangesSection of the release
What
A new internal remedy field can be attached to a tool result's metadata (tool_result_meta), giving a structured reason for a failure instead of free text. Its possible values include mcp_needs_auth, mcp_disabled, mcp_required_missing, auth_expired, auth_overridden, auth_missing_scope, design_needs_authorization, sandbox_violation, outside_reads_blocked, memory_paused, feature_disabled, policy_denied, spawn_arg_limit, and staged_for_review.
This remedy is now threaded through as toolResultRemedy when building the tool-result message shown to Claude, and included in the transcript summary for denied or blocked tool calls alongside the existing non_execution_kind.
Errors produced after a failed tool call now include toolResultRemedy next to the existing toolDenialKind, both produced by new classifier functions that turn internal permission-deny and connection/auth failures into these structured kinds.
Why
This lets tools and host applications programmatically detect why a call failed, for example missing MCP authorization versus a sandbox violation, and suggest the right fix instead of relying on parsing human-readable error text.
