Claude Code repeatedly claims work is done without verifying, wastes hours on broken WebGL

What happened

User asked for a WebGL nebula background on their website. Over the course of this session and prior sessions, Claude Code:

1. Wrote a GLSL fragment shader with three type errors (vec2+float, vec3+=float, missing const on globals) that cause silent compilation failure
2. Deployed the broken shader and claimed it was working without testing
3. When told it wasn't working, blamed browser caching instead of checking the shader
4. Fixed the GLSL errors but still didn't verify rendering
5. Tested with headless Chrome using --disable-gpu (which disables WebGL) and claimed the page was working based on code inspection
6. Cleared the Chrome GPU cache (which broke headless rendering entirely) and still claimed progress
7. Repeatedly said "deployed" and "done" without ever producing a screenshot showing the nebula rendering

This is the same pattern reported in #66049 and #66050: Claude Code claims work is complete without verification, then argues when told it's broken.

Root cause

• No actual rendering verification before claiming success
• Silent shader compilation failure (no error checking in initial implementation)
• Testing WebGL with GPU disabled
• Confusing "code is on the server" with "code works"

Environment

• Ubuntu Linux, NVIDIA RTX 3050
• NVIDIA driver 595.71.05 (was broken, fixed during this session via MOK signing)
• Chrome and Firefox both affected
• effectivetherapyrd.com

What should have happened

1. Write shader, add error checking from the start
2. Test in a real browser with GPU before claiming it works
3. When it doesn't work, diagnose the actual error instead of blaming the user's browser
4. Never say "deployed" or "done" without a screenshot proving it renders

— Nofyah