Arise

Introducing WebMCP: Agents in the Browser — RL Nabors

May 23, 2026 · 23:08

Rachel Nabors, former web standards contributor and now Principal Developer Experience Engineer at Arise, argues that chat-only agent interfaces (the 'starfish' design) are the CLI of the future and demonstrates how to replace them with rich interactive surfaces using MCP Apps and WebMCP. She explains STDIO vs HTTP transports, shows how MCP Apps bundle HTML, CSS, and JavaScript into single files rendered in agent iframes, and introduces WebMCP, which adds tool attributes to existing page elements so browser agents can call functions without screenshot parsing or DOM traversal. Using her own web comic site as a case study, she builds a comic reader with full panel navigation, transcript mode, and speech synthesis via the Web Speech API, and advocates for better client support of MCP resources to avoid inefficient tool calls for context loading.

Break It 'Til You Make It: Building the Self-Improving Stack for AI Agents - Aparna Dhinakaran

Jun 10, 2025 · 14:25

Aparna Dhinakaran, co-founder of Arise, details how to build a self-improving evaluation stack for AI agents using her company's open-source tools Arise Phoenix and RiseX. She argues that production agents require three evaluation layers: tool-call correctness (right function and arguments), trajectory accuracy (correct order of steps), and multi-turn session consistency (context retention). Dhinakaran demonstrates with real traces from Arise's own Copilot, showing how a bottleneck in search Q&A correctness (only 50% accuracy) was traced to incorrect argument passing in a tool call. She stresses a dual iteration loop: improving agent prompts and simultaneously refining eval prompts (LLM-as-judge) to avoid static evaluation criteria. The talk concludes that continuous eval improvement is essential for agents to move from working once to working reliably in production.