
Trailblaze
https://github.com/block/trailblaze- Category
- Developer Tools
- Rank
- No. 789Tools index
- Listed in
- #3 Generate and improve tests
- Pricing
- Open Source
- Type
- TOOL
- Builder
- block
- GitHub
- 310 stars
- Latest release
- v2026.09.02
- Date
About
AI-driven UI testing framework for Android — describe what you want to test in plain language and let the agent drive the app.
What it does
Trailblaze turns an exploratory device session into a readable test artifact. It captures intent alongside concrete UI actions, stores platform-specific recordings in one YAML trail, then replays those recordings deterministically in CI without calling an LLM.
Why it's ranked here
The design connects agent-led exploration to conventional regression testing unusually well. Android, iOS, and web share one authoring model while retaining native accessibility, semantics, and DOM capabilities. Replayable artifacts and detailed traces make the result more accountable than an opaque autonomous test run.
What's good
Recorded intent gives failed selectors useful repair context. Replay remains deterministic by default, while optional self-healing handles small interface drift. Reports combine screenshots, hierarchy snapshots, tool calls, transcripts, video, and performance timelines. Teams can also add typed TypeScript commands for app-specific operations.
Tradeoffs
Agent-driven steps require a configured LLM provider, and useful visual flows need a model with image input and tool calling. GitHub-release installation requires Java 17 or newer. Video reporting needs an optional dependency. Maestro compatibility covers interactions but excludes JavaScript, subflows, and environment variables.
How to use it well
Use it when a coding agent already participates in development and you want exploratory device work to become committed cross-platform regression tests. Build reusable domain commands for repeated flows, then replay recordings in CI. It does not replace a coding agent or provide a hosted SaaS testing platform.
Technical notes+
README.md defines the CLI-first capture and replay workflow, Homebrew and release installation, bundled agent skill, desktop app, and unified trail artifact. docs/architecture.md describes a Kotlin and Gradle multi-module system using coroutines, serialization, Compose Multiplatform, Ktor, platform drivers, and recorded YAML execution. docs/CLI.md documents shell commands plus an MCP server, persistent device sessions, deterministic runs, reports, profiling, and validation. docs/tools.md specifies TypeScript, pure-YAML, and Kotlin-backed extension mechanisms. docs/llms.md exposes library integration through Koog's LLMClient and TrailblazeRunner. docs/maestro.md states that only part of Maestro's command model is implemented.
Observed
- License
- Apache 2.0
- Primary language
- Kotlin, including Kotlin Multiplatform modules
- Install surface
- Homebrew formula or GitHub release installer; release installation requires Java 17 or newer
- Interfaces
- CLI, MCP server, desktop application, and Kotlin library integration
- Platforms
- Android, iOS, and web
- Test artifact
- One YAML trail can hold natural-language intent and platform-specific recordings
- Replay model
- Recorded trails replay deterministically without an LLM by default
- Custom tools
- Supports TypeScript scripted tools, pure-YAML composed tools, and Kotlin-backed tools
Read from README.md, docs/CLI.md, docs/llms.md, docs/index.md, docs/tools.md, docs/logging.md, docs/maestro.md, docs/reports.md, docs/support.md, docs/profiling.md, docs/trailmaps.md, docs/architecture.md, docs/configuration.md, docs/adding_a_model.md.
What it can do
Generate UI test automation from natural language descriptions
Plain language test description → Automated UI test script
Execute automated UI tests on Android applications
Test script and target Android app → Test execution results and status
Navigate Android app interfaces autonomously
Test objectives and target app UI → Simulated user interactions and navigation paths
Interpret user intent for mobile app testing
Natural language testing requirements → Structured test plan and actions
Drive mobile app interactions without manual scripting
Testing goals and Android application → Automated touch, swipe, and input actions
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Editorially curated, with community endorsements as a secondary signal. Corrections welcome.