Deferred tools appear in tool list but fail to execute in voice mode

Tools discovered via tool search appear in the available tools list and show their full schema, but when invoked via function call, they return a "tool not registered" error. This occurs in voice mode where the tool was freshly loaded via deferred tool mechanism. The GitHub tools were successfully discovered and their parameters displayed, but calling GitHub search issues returned "Error: tool GitHub search issues is not registered. This may indicate a tool name hallucination or a stale tool schema."

Expected behavior: deferred tools should be fully registered and executable once they appear in the available tools list.

Actual behavior: tools are discoverable but not callable, creating a gap between what the system reports as available and what actually executes.

Environment: Claude voice mode.

Related: this may be connected to issue #36060 regarding tools not loading across different Claude interfaces.