Agent surfaces

Everything a Max agent says happens on .maxchat, a scoped surface with its own language, shown on the MaxChat card:

• Cool neutrals: mx-bg, mx-surface, mx-surface-2, mx-surface-hi, mx-ink … mx-ink-4, mx-line, mx-line-strong — hue 260°, set apart from the app's warm stone. Text uses mx-ink to mx-ink-3 (5.5:1 or better); mx-ink-4 is for placeholders and marks only.
• Two accents, never orange: accent-ai purple for AI activity (thinking, tool calls, links, the drop zone, chip hover) and accent-new green for live status (online dot, connected tools, done). Primary buttons on agent surfaces are ink (mx-ink on mx-bg).
• Prose, not bubbles: Max's replies are 14.5px paragraphs with no box; the user's own messages are right-aligned italic in mx-ink-2. Tables, code and links sit inline.
• Show the work: a collapsible thinking box lists thoughts and tool calls with their state (running pulses purple, done green, failed red), and a meta line such as "3 tools · 6s".
• Ask before acting: anything that sends, spends or changes data appears as a confirm card with the draft and the choice; the foot note says what needs confirmation.
• Faces: every agent shows its portrait or accent-tile initials (AgentFace) and a name; the empty state greets in Instrument Serif ("Hey, I’m Max.") with three suggestion chips.