triage-flaky-test

Triage Flaky Test

One-line summary: Investigate a specific flaky test — get history, failure pattern, and category, then recommend fix, quarantine, or escalate.

Requires: dd-pup skill (pup CLI installed and authenticated).

Backend

Detection — At the start of every invocation, before taking any action, determine which backend to use:

1. If the user passed --backend pup anywhere → use pup mode immediately. Skip steps 2–4.
2. Check whether get_datadog_flaky_tests appears in your available tools.
3. If present → use MCP mode throughout. Call tools exactly as named in this skill's workflow sections.
4. If absent → check whether pup is executable: run pup --version via Bash. If the command exits successfully (exit code 0), pup is available.
5. If pup responds → use pup mode throughout. Translate every tool call using the Tool Reference appendix at the bottom of this file.
6. If neither is available → stop and tell the user:

   "Neither the Datadog MCP server nor the pup CLI is available. Connect the MCP server or install pup (brew install datadog-labs/pack/pup)."

pup invocation rules:

• Invoke via Bash. pup always outputs JSON — parse directly.
• Repository IDs passed to pup must be fully lowercase (the API rejects mixed-case).
• Sort values starting with - require = syntax: --sort="-last_flaked" (not --sort "-last_flaked").
• If pup returns a 401/403, tell the user to run pup auth refresh or pup auth login.

Input

Workflow

STEP 0 — Parse Input

Derive repository ID from git if not provided:

git remote get-url origin
# Strip protocol and trailing .git, then lowercase the result
# e.g. https://github.com/DataDog/my-repo.git → github.com/datadog/my-repo

Validation fallback: If STEP 1 returns no results, confirm the correct repository by searching without a repo filter:

Tool: search_datadog_test_events
query: @test.name:"<test-name>"
from: now-30d
test_level: test

Extract @git.repository.id_v2 from results and retry STEP 1 with the confirmed value.

STEP 1 — Get Flaky Test Details

Preferred — use fingerprint_fqn if known (fingerprint_fqn is a valid CI Visibility search facet):

Fallback — use name + suite + repo:

Omit @test.suite if unknown. Do not filter by flaky_test_state — return the test regardless of state.

Note: the query filter facet is flaky_test_state; the returned response attribute is flaky_state — do not use flaky_state:active as a query filter.

Extract from results:

• fingerprint_fqn — unique test identifier; used as the id in STEP 5 write call. If absent, do not proceed to quarantine — see STEP 5.
• flaky_state — current state (active / quarantined / disabled / fixed)
• test_stats.failure_rate_pct — percentage of runs that fail
• flaky_category — root cause category
• codeowners — owning team
• pipeline_stats.total_lost_time_ms — total CI time lost

STEP 2 — Get Recent Failure History

Extract:

• Error messages and stack traces (@error.message, @error.stack)
• Failing branches (@git.branch) — branch-specific vs. widespread
• Frequency pattern — random timing or specific conditions
• Unique @ci.pipeline.id values for blast radius (STEP 3)

STEP 3 — Check Blast Radius

Count distinct pipelines impacted using pipeline IDs from STEP 2:

Use the first 10 pipeline IDs from STEP 2 (cap at 10; if more are available, run a second batch and merge results by summing counts per @ci.pipeline.name across batches). Report blast radius as: total number of unique pipelines impacted and whether failures are branch-specific or widespread.

Note: a pipeline failure is not necessarily caused solely by this flaky test — treat blast radius as a signal, not a definitive count.

STEP 4 — Recommend Fix or Quarantine

Use flaky_category from STEP 1 and error messages from STEP 2.

Root cause first:

• Read the full error trace from bottom to top — chained errors hide the real cause; the innermost error is the root cause, not the first line.
• Identify the exact source of nondeterminism (race, ordering, stale state, timing).
• If the root cause is a CI infrastructure problem (runner unavailable, Docker daemon failure, network outage) → do NOT propose a code fix; classify as infra and recommend retry instead.
• If root cause is uncertain and cannot be confirmed from the stack trace → skip fix, go to quarantine.

Fix at the correct layer:

• Test issue → fix in test or test helper only.
• Production bug exposed by the test → fix in production code.
• Shared helper used by multiple tests → fix the helper AND update all call sites.

Forbidden — do not propose these:

• Timing hacks: increasing timeouts, adding sleeps, widening time windows, adding retries.
• Masking: relaxing assertions (e.g., exact match → at least 1), dropping validations.
• Partial fixes: touching one call site when multiple share the root cause.

Fix patterns by category:

Before proposing code changes, verify all of the following — if any fails, skip fix and recommend quarantine:

• The root cause is the innermost error in the trace, not a surface-level symptom.
• The failure is a code problem, not a CI infrastructure problem.
• The fix eliminates the root cause (not just reduces flake probability).
• The fix is at the correct layer (test vs. production vs. shared helper).
• All call sites of any shared code are updated.
• No timing hacks or relaxed assertions introduced.

Decision:

• If category is unknown OR verification above fails → skip fix, recommend quarantine
• If category is known AND root cause is confirmed AND fix is valid → propose specific code change

STEP 5 — Produce Triage Brief and Act

Decision thresholds:

• failure_rate_pct > 10 OR blast radius > 5 pipelines → quarantine
• failure_rate_pct ≤ 10 AND known category AND clear fix → fix
• failure_rate_pct ≤ 10 AND category unknown → escalate to codeowners with triage brief

If recommending quarantine, present and require explicit user approval before writing:

If fingerprint_fqn was not returned in STEP 1 (test not yet in FTM or query returned no results): do not attempt the write. Surface an error and ask the user to open the Flaky Test Management UI directly to quarantine manually.

Only after explicit approval and a confirmed fingerprint_fqn:

MCP mode:

pup mode:

To undo: repeat with new_state: active / "new_state": "active".

Tool Reference

This appendix applies only in pup mode. In MCP mode, use the tool names in the workflow sections directly.