Reticle is a developer tool that forces AI coding agents to verify their changes by driving the real running app and returning a concrete verdict: PASS, FAIL, or CANNOT TELL. It embeds a small dev-only SDK into an app so agents can look, act, observe and assert against network responses, app state (Redux, Zustand, TanStack Query, Pinia, etc.), console output, renders and the source line for each element. Every check produces evidence (the request, state change and console line that decided it) and a file:line to fix; only a definitive "yes" counts as a pass. It can record deterministic replayable flows, surface failures in CI as a gate, and shows a HUD of the agent’s actions and verdicts while running locally.
The SDK is designed for safety and developer control: development builds only, bridge on 127.0.0.1, Chromium-driven, no production shipping, and nothing leaves the machine unless a project is explicitly linked. It integrates with many agents and frameworks (Claude Code, Cursor, Codex, Gemini, VS Code; React, Next.js, Vue, Svelte, Angular, Electron, Tauri) and includes signed builds, no install scripts, prompt capture in .reticle, opt-out telemetry, and documented provenance. The tool emphasizes reproducible verification over optimistic code generation to prevent shipped regressions agents would otherwise miss.
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