Get started

Coffilot is a GitHub Copilot canvas extension: it lives in a .github/extensions/coffilot/ folder (committed to a repo, shared with the team) or in $COPILOT_HOME/extensions/coffilot/ (~/.copilot/extensions/coffilot/, just for you).

Requirements

  • The GitHub Copilot app or Copilot CLI with canvas-extension support.
  • Node.js 20+ — the runtime the Copilot CLI uses to launch the extension.
  • A target project built with Maven or Gradle on Java 17+. The committed wrapper (./mvnw or ./gradlew) is used when present, otherwise a system mvn / gradle on PATH. Works on macOS, Linux and Windows. If both build tools are present, Maven is used.
  • Optional: mvnd for warm Maven builds (the Gradle daemon serves the same role and is always available), and BootUI on the target app for the richest metrics and advisor scans.

Install

From the Copilot app

Use Install extension from repo… (or the install_extension action) and point it at this repository:

https://github.com/jdubois/coffilot

Choose project scope to commit it into the current repo's .github/extensions/, or user scope to install it just for you.

Manually

Copy the extension files into the target location, keeping the folder name coffilot:

# Project scope (committed to the repo you want to drive):
mkdir -p .github/extensions/coffilot
cp -R extension.mjs copilot-extension.json public .github/extensions/coffilot/

# Or user scope (available in every session):
mkdir -p ~/.copilot/extensions/coffilot
cp -R extension.mjs copilot-extension.json public ~/.copilot/extensions/coffilot/

Reload extensions (or restart the session); Coffilot is then discovered automatically (canvasId: java-app).

Use

In a Copilot app session on a Maven or Gradle project, open the Coffilot canvas, then:

  1. Build to compile the project (first run), or Run to start an app (pick a module and a run profile).
  2. Watch the console stream the build-tool / app output.
  3. Once the app is up, watch the Live JVM metrics panel populate (badge: BootUI / Actuator / Quarkus / process).
  4. If something fails, click Fix with Copilot to hand the error to the agent.
  5. Or Debug instead of Run to launch under the debugger: open the Debug tab, add a breakpoint (class binary name + line), and use Continue / Step / Pause; the paused call stack, frame variables and an evaluator appear inline.
  6. Stop when done.

Drive it from the agent

The agent can drive the same flow with the build_app, run_tests, run_affected_tests, package_app, start_app, stop_app, get_status, get_metrics, profile_app, fix_issue, run_scan, check_dependencies and set_log_level actions, plus the debug actions start_debug, stop_debug, set_breakpoint, remove_breakpoint, debug_continue, debug_step, debug_stack, get_variables, debug_evaluate and debug_status.

Next steps

  • Read the full Features tour.
  • See how Coffilot pairs with BootUI and Dr JSkill in the Ecosystem page.