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).

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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.

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Input

Parameter	Description
Test name	Fully qualified test name (e.g. TestMyFunc or com.example.MyTest)
Repository	Lowercase, no-schema URL (e.g. github.com/org/repo). Derive from git remote get-url origin if not provided.

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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):

Tool: get_datadog_flaky_tests
query: fingerprint_fqn:<fqn>
sort_field: last_flaked
sort_order: desc

Fallback — use name + suite + repo:

Tool: get_datadog_flaky_tests
query: @test.name:"<test-name>" @test.suite:"<suite>" @git.repository.id_v2:"<repo>"
sort_field: last_flaked
sort_order: desc

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

Tool: search_datadog_test_events
query: @test.name:"<test-name>" @test.suite:"<suite>" @test.status:fail @git.repository.id_v2:"<repo>"
from: now-7d
test_level: test

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:

Tool: aggregate_datadog_ci_pipeline_events
query: @ci.status:error @ci.pipeline.id:(<id1> OR <id2> OR ...) @git.repository.id_v2:"<repo>"
ci_level: pipeline
aggregation: count
group_by: ["@ci.pipeline.name"]
from: now-7d

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:

Category	Approach
timeout	Identify the slow operation and make it synchronous or deterministic — do NOT simply raise the timeout constant
concurrency	Add deterministic synchronization (barriers, channels, locks); remove shared mutable state between tests
network	Mock or stub network calls at the boundary; if the test requires a real connection, isolate it with a test server
time	Inject a controllable clock; replace wall-clock assertions with relative or event-driven checks
order_dependency	Isolate test state with setup/teardown; eliminate dependencies on execution order or global state
environment_dependency	Mock env variables and external config; use test-local fixtures, not shared directories or singletons
resource_leak	Ensure every resource opened in a test is closed in teardown; use cleanup hooks that run even on failure
randomness	Fix the random seed for the test run; use deterministic inputs instead of random generation
asynchronous_wait	Replace fixed sleeps with condition polling or event/signal-driven waits with a hard timeout
io	Use temp files/dirs cleaned up in teardown; mock or stub filesystem interactions
unknown	Skip fix attempt → go to quarantine

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

Flaky Test Triage Brief
=======================
Test:           <fully qualified test name>
Service:        <@test.service>
Category:       <flaky_category>
Failure Rate:   <test_stats.failure_rate_pct>%
Duration Lost:  <pipeline_stats.total_lost_time_ms>ms
Codeowners:     <codeowners>
Blast Radius:   <N> pipelines (<branch-specific | widespread>) [approximate — other failures in the same pipeline runs may not be related]

Evidence:
  <1-2 key error message lines from STEP 2>

Recommendation: <fix | quarantine | escalate>
Confidence:     <high | medium | low>
Action:         <specific next step>

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:

Proposed action: quarantine "<test-name>"
  id (fingerprint_fqn): <fingerprint_fqn from STEP 1>
  Effect: test still runs but failures are suppressed (CI will not be blocked)
  Reversible: yes — set new_state: active to restore

Approve? (yes/no)

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:

Tool: update_datadog_flaky_test_states
test_ids: ["<fingerprint_fqn>"]
new_state: quarantined

pup mode:

cat > /tmp/flaky-update.json <<'EOF'
{
  "data": {
    "type": "UpdateFlakyTestsRequest",
    "attributes": {
      "tests": [{"id": "<fingerprint_fqn>", "new_state": "quarantined"}]
    }
  }
}
EOF
pup test-optimization flaky-tests update --file /tmp/flaky-update.json

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

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Tool Reference

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

MCP Tool	pup Command
get_datadog_flaky_tests (by fingerprint_fqn)	pup cicd flaky-tests search --query "fingerprint_fqn:<fqn>" --sort="-last_flaked" --limit 5
get_datadog_flaky_tests (by name + suite + repo)	pup cicd flaky-tests search --query "@test.name:\"...\" @test.suite:\"...\" @git.repository.id_v2:\"...\"" --sort="-last_flaked" --limit 10
search_datadog_test_events (validation fallback)	pup cicd tests search --query "@test.name:\"<test-name>\"" --from 30d --limit 5
search_datadog_test_events (failure history)	pup cicd tests search --query "@test.name:\"...\" @test.suite:\"...\" @test.status:fail @git.repository.id_v2:\"...\"" --from 7d --limit 20
aggregate_datadog_ci_pipeline_events (blast radius)	pup cicd events aggregate --query "@ci.status:error @ci.pipeline.id:(...) @git.repository.id_v2:\"...\"" --compute count --group-by "@ci.pipeline.name" --from 7d
update_datadog_flaky_test_states	Write body to /tmp/flaky-update.json, then pup test-optimization flaky-tests update --file /tmp/flaky-update.json