Stall to alert color escalation

SKILL: Stall-to-Alert Color Escalation

Domain: terminal-ui Trigger: Use when a spinner or progress indicator should warn about stalls without replacing itself with a larger warning UI. Source Pattern: Distilled from reviewed stall-sensitive terminal indicator rendering patterns.

Core Method

Start with the indicator's normal theme color, then interpolate it toward a known alert color as stall intensity rises. If exact color math is unavailable, fall back to a semantic alert token instead of failing. This creates a smooth escalation path that preserves the indicator's footprint while still making degraded states obvious.

Key Rules

• Drive the escalation from a normalized stall intensity rather than fixed hardcoded time branches inside the renderer.
• Keep a safe fallback path when literal color parsing fails.
• Preserve the same spinner or indicator footprint while only changing color and, if needed, subtle glyph intensity.

Example Application

For a long-running build spinner, fade the normal accent color toward red as the system detects a likely stall, while keeping the same single-cell spinner slot.

Anti-Patterns (What NOT to do)

• Do not swap the spinner for a larger banner at the first sign of delay.
• Do not hardcode one threshold and one end-state color without a smooth ramp.
• Do not let stall visuals change the indicator's size or alignment.