frontend-runtime-skills-contract

What problem does it solve?

It prevents the frontend from executing or rendering unsafe, mismatched, or unregistered capabilities when it receives streamed tool-call data from agents.

Core Features & Use Cases

• Runtime Capability Registry Contract: centralizes the mapping from toolName to component, behavior, risk level, and failure mode without binding to any specific agent.
• Tool Call Arg Aggregation + Validation: aggregates fragmented args by toolCallId, parses JSON at TOOL_CALL_END, and validates against parametersSchema before executing.
• Security-Aware Rendering and Degradation: enforces sandboxing rules (e.g., iframe for web_preview), disables reserved/disabled capabilities, and applies consistent fallback behavior (error cards, placeholders, or text fallback) to avoid white screens.
• ToolResult Boundary Guidance: defines when ToolResult should or should not be returned, including safe error/error-card practices.

Quick Start

Register your frontend runtime capabilities in the Runtime Capability Registry keyed by toolName and then render only after the tool call ends, JSON parses, schema validates, and the registry status/risk policy allows execution.