A CLI tool that runs regression tests on AI coding agent behavior across model updates.

When Anthropic or OpenAI ships a model update, engineering teams have no way to know if their AI coding agent still follows the same instructions and produces the same UI output it did before. Developers discover regressions only after burning hours on broken outputs or catching hallucinated 'task complete' claims post-merge. This CLI captures a baseline of agent behavior (instruction-following plus visual UI snapshots) and flags drift automatically whenever the underlying model changes.

Demand Breakdown

Issues

3,290

943

Social Proof 3 sources

Claude Code is unusable for complex engineering tasks with the Feb updates

@gh:stellaraccident · 2026-04-02

3,290 HN

AI agents: Less capability, more reliability, please

@serjester · 2025-03-31

676 HN

Show HN: ProofShot - Give AI coding agents eyes to verify the UI they build

@jberthom · 2026-03-24

267

Gap Assessment

CompetitiveMultiple tools exist but differentiation opportunities remain

3 tools exist (ProofShot, Playwright, Anthropic/OpenAI Evals) but gaps remain: Only covers visual UI output, not instruction-following or task-completion accuracy. No model-update regression tracking.; Tests app behavior, not agent behavior. Cannot tell an agent hallucination from a real app regression..

Features2 agent-ready prompts

Behavioral baseline capture + drift diff engine: agent instructions + response corpus in, signed baseline file out; diff flags instruction-following changes on each model update

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Visual UI snapshot verification loop: agent-generated UI in, screenshot diffs out; flags pixel-level regressions against a locked visual baseline after each model or agent update

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Competitive LandscapeFREE

Product	Does	Missing
ProofShot	Gives AI coding agents a screenshot-based visual check after UI generation.	Only covers visual UI output, not instruction-following or task-completion accuracy. No model-update regression tracking.
Playwright	Headless browser automation and end-to-end UI testing.	Tests app behavior, not agent behavior. Cannot tell an agent hallucination from a real app regression.
Anthropic/OpenAI Evals	Prompt-level evaluation of model outputs against expected answers.	For model builders, not agent users. No CLI in an agentic workflow, no visual snapshot diffing, no per-project behavior baseline.