LUCI Build Triage & Analysis

This skill provides access to specialized triage tools maintained within the depot_tools repository. These tools are used to inspect Buildbucket results and ResultDB test failures.

Environment & Auth Discovery

• Environment: Always execute these scripts using vpython3 instead

of python3 to ensure all hermetic dependencies (like httplib2) are satisfied.

• Authentication: Use bb auth-info to proactively check if you are

logged into Buildbucket. If not, inform the user they must run bb auth-login.

Locating the Tools

The triage scripts and their detailed documentation are located relative to the depot_tools installation:

1. Locate Depot Tools: Run which gerrit_client.py to find your local

depot_tools root.

1. Navigation:

• Buildbucket (bb_wrapper.py): Found in <DEPOT_TOOLS_ROOT>/agents/skills/buildbucket/
• Strengths: High-level Build info (is it failing? what steps failed?),

compile errors, and infra issues.

• Test Results (luci_triage.py): Found in <DEPOT_TOOLS_ROOT>/agents/skills/luci-test-results/
• Strengths: Detailed Test info (specific test case failures in

ResultDB).

Troubleshooting

• "No Artifacts Found": This usually occurs if:

1. The build failed so early (e.g., bot setup) that no artifacts were produced.
2. The build is too old and logs have been purged.
3. There is an authentication issue.

• Fallback: Try bb log <build_id> <step_name> to see the raw output

for the failed step.

Available Skills in Depot Tools

Once you have located the depot_tools directory, read the following files to understand how to use each tool:

• buildbucket: Used for high-level builder status and compile failures.
• Read: <DEPOT_TOOLS_ROOT>/agents/skills/buildbucket/SKILL.md
• luci-test-results: Used for detailed ResultDB test failure analysis.
• Read: <DEPOT_TOOLS_ROOT>/agents/skills/luci-test-results/SKILL.md

Usage at Runtime

When you need to triage a build:

1. Locate depot_tools as described above.
2. Read the relevant SKILL.md file from depot_tools.
3. Follow the instructions in that file to execute the Python scripts (e.g.,

bb_wrapper.py or luci_triage.py) using their absolute paths.