Interactive demo
Silent when passing. Specific when failing.
Every AI agent edit triggers tailtest. It generates production-like scenarios, runs them, and surfaces only what fails. If everything passes, you never see it.
simulated demo -- no code runs in your browser
How it works
Two trigger models. Same test cycle.
Claude Code, Cursor, and Codex CLI use host-native hooks. Cline uses an MCP server. Both end at the same place: tests written, run, and surfaced.
Claude Code's PostToolUse, Cursor's afterFileEdit, and Codex's Stop hooks all call tailtest on every file edit. No commands, no prompts.
Scenarios are generated for what your AI just built and run immediately against your test runner.
Failures are injected into the AI's next turn via the host's context channel. When everything passes, nothing is injected -- the AI emits a brief confirmation and moves on.
Cline has no host hooks. The .clinerules baseline tells the agent to call the MCP tool after every edit. Auto mode + auto-approve = hands-off; manual mode = explicit slash.
The MCP tool returns structured data the agent uses to compose the SCENARIO PLAN. Deterministic logic in code; creative scenario authoring in the agent.
Each failure is structured-classified by R12: real_bug / environment / test_bug. Cline reaches 8+ editors via Cline's host coverage; same MCP server runs in all of them.
Get started in 60 seconds
Add tailtest to your AI coding workflow
Pick your editor. Same R1-R15 rule layer + adversarial test mode in all four variants.
Not sure which? Compare the variants (1-minute read).