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triage-flaky-test

โ˜… 139

by datadog-labs ยท part of datadog-labs/agent-skills

Load when investigating a specific flaky test. Gets history, failure pattern, and category, then recommends fix, quarantine, or escalate.

๐Ÿงฉ One of 7 skills in the datadog-labs/agent-skills package โ€” works on its own, and pairs well with its siblings.

This is the playbook your agent receives when the skill activates โ€” you don't need to read it to use the skill, but it's here to audit before installing.

Triage Flaky Test

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

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


Backend

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

  1. If the user passed --backend pup anywhere โ†’ use pup mode immediately. Skip steps 2โ€“4.
  2. Check whether get_datadog_flaky_tests appears in your available tools.
  3. If present โ†’ use MCP mode throughout. Call tools exactly as named in this skill's workflow sections.
  4. If absent โ†’ 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 โ†’ use pup mode throughout. Translate every tool call using the Tool Reference appendix at the bottom of this file.
  6. If neither is available โ†’ 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 โ€” 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

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

Workflow

STEP 0 โ€” 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 โ†’ 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 โ€” Get Flaky Test Details

Preferred โ€” 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 โ€” 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 โ€” return the test regardless of state.

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

Extract from results:

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

STEP 2 โ€” 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) โ€” branch-specific vs. widespread
  • Frequency pattern โ€” random timing or specific conditions
  • Unique @ci.pipeline.id values for blast radius (STEP 3)

STEP 3 โ€” 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 โ€” treat blast radius as a signal, not a definitive count.

STEP 4 โ€” 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 โ€” 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) โ†’ 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 โ†’ skip fix, go to quarantine.

Fix at the correct layer:

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

Forbidden โ€” do not propose these:

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

Fix patterns by category:

CategoryApproach
timeoutIdentify the slow operation and make it synchronous or deterministic โ€” do NOT simply raise the timeout constant
concurrencyAdd deterministic synchronization (barriers, channels, locks); remove shared mutable state between tests
networkMock or stub network calls at the boundary; if the test requires a real connection, isolate it with a test server
timeInject a controllable clock; replace wall-clock assertions with relative or event-driven checks
order_dependencyIsolate test state with setup/teardown; eliminate dependencies on execution order or global state
environment_dependencyMock env variables and external config; use test-local fixtures, not shared directories or singletons
resource_leakEnsure every resource opened in a test is closed in teardown; use cleanup hooks that run even on failure
randomnessFix the random seed for the test run; use deterministic inputs instead of random generation
asynchronous_waitReplace fixed sleeps with condition polling or event/signal-driven waits with a hard timeout
ioUse temp files/dirs cleaned up in teardown; mock or stub filesystem interactions
unknownSkip fix attempt โ†’ go to quarantine

Before proposing code changes, verify all of the following โ€” 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 โ†’ skip fix, recommend quarantine
  • If category is known AND root cause is confirmed AND fix is valid โ†’ propose specific code change

STEP 5 โ€” 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 โ€” 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 โ†’ quarantine
  • failure_rate_pct โ‰ค 10 AND known category AND clear fix โ†’ fix
  • failure_rate_pct โ‰ค 10 AND category unknown โ†’ 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 โ€” 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".


Tool Reference

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

MCP Toolpup 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_statesWrite body to /tmp/flaky-update.json, then pup test-optimization flaky-tests update --file /tmp/flaky-update.json