Two tools with clear, action-oriented names (open_canvas, describe_sketch) and reasonable descriptions (150 - 180 chars, within baseline 34 - 392 range). Both have identical input schemas with a single optional 'hint' parameter. However, parameter descriptions are minimal ('Optional reminder shown above the canvas'), and output schemas are completely undocumented, LLMs cannot plan downstream steps or extract structured data. No error handling guidance, no recovery paths, and no indication of what fields the returned image contains or how to use it. Tool composition is sound (each does one thing), but the lack of output documentation and error guidance significantly limits production readiness.

• Document output schema for both tools: specify that the return value is a base64-encoded PNG string, include field name (e.g., 'image'), and explain how downstream tools should consume it.
• Add error handling guidance: 'If the user closes the canvas without submitting, the tool returns null. If a network error occurs, retry after 5 seconds. If the canvas fails to load, check browser console for errors.'
• Expand 'hint' parameter description: 'Optional text reminder displayed above the canvas (max 200 chars). Use to guide the user (e.g., "Draw a wireframe of the login page").'
• Clarify describe_sketch return value: 'Returns both the sketch image (base64 PNG) and a text description generated by the agent. Use when you need both visual and textual representations.'
• Add tool-level prerequisites: 'Requires a local browser and network access to 127.0.0.1. The canvas server runs on a random port and opens automatically.'