Detect Permafail

Detect Permafail

When to Use This Skill

Use this skill when you have 2-10 consecutive failures of the same job and need to determine if the failures represent a systematic/permanent failure (permafail) versus a flaky failure. This is critical for CI/CD pipeline analysis to distinguish between:

• Permafail: A systematic failure affecting the same test(s) or infrastructure issue, detected by analyzing comparable runs (same failure type):
  • 2-3 comparable runs: All must have the same failure (100% match)
  • 4-5 comparable runs: At least 4 must have the same failure (80% match)
  • 6-10 comparable runs: At least ceil(count × 0.7) must have the same failure (70% match)
• Flaky: Non-deterministic failures with varying root causes, or failures that don't meet the permafail thresholds

Prerequisites

• Access to OpenShift CI Prow job artifacts via gcsweb URLs
• Access to the Bash tool for running plugins/ci/scripts/classify-job-failures.py
• Python with the requests package available for artifact fetching
• Knowledge of Prow artifact structure (from fetch-prowjob-json and prow-job-artifact-search skills)
• 2-10 URLs pointing to consecutive job failures (from Prow/OpenShift CI, ordered newest to oldest)
• Job name context to verify consistency across all failures
• PR information to provide context for analysis

Implementation Steps

Step 1: Validate Inputs

Standard Mode (URL-based):

Verify that all required inputs are present with expected types and constraints:

• failure_urls: Array of 2-10 strings matching Prow job URL pattern https://prow.ci.openshift.org/view/gs/<bucket>/<path>/<job-name>/<build-id> where path may be logs/, pr-logs/pull/, or other GCS paths (must be consecutive runs, ordered newest to oldest)
• job_name: Non-empty string identifier of the job being analyzed
• pr_info: Object containing PR number (integer) and repository context (string)
• Each URL must match the Prow job URL pattern above

Reject requests if:

• URLs count is less than 2 or more than 10
• Job names don't match across all URLs (validate via prowjob.json metadata, not path position)
• PR context is missing

Notes:

• URL ordering (newest first) is assumed but not validated - the frontend provides them in this order
• Job name validation should check prowjob.json metadata or verify the name appears in the extracted GCS path, not assume a fixed path position (presubmit URLs include org/repo/pr segments)

Offline/Eval Mode (Pre-normalized Signatures):

For testing or offline analysis, the skill can accept pre-normalized failure signatures directly instead of fetching from URLs. This mode skips Steps 2-4 (artifact fetching and classification) and proceeds directly to Step 5 (threshold analysis).

Input format:

• signatures: Array of 2-10 pre-normalized signature objects (see Step 4 output format)
• Each signature must be either test_failure format {type: "test_failure", url: "...", tests: [...], test_count: N} or infra_failure format {type: "infra_failure", url: "...", error: "...", error_hash: "..."}

When signatures are provided, skip to Step 5 and apply threshold logic directly. Use this mode only for evals or when signatures have been extracted by another tool.

Step 2: Classify Job Failures with Script

For standard URL-based analysis, call the deterministic classifier script to fetch artifacts and produce normalized signatures:

"$SKILL_DIR/../../scripts/classify-job-failures.py" --json-input '{
  "failure_urls": ["https://prow.ci.openshift.org/view/gs/..."],
  "job_name": "pull-ci-openshift-origin-master-e2e-aws",
  "pr_info": {"pr_number": 12345, "repository": "openshift/origin"}
}'

The script performs the artifact-based work that does not require AI judgment:

1. Parses the full GCS path from each Prow URL.
2. Fetches prowjob.json from gcsweb.
3. Browses the artifacts directory.
4. Classifies each run as test_failure or infra_failure based on artifacts, not error text alone.
5. Extracts failing test names from junit/build logs or normalized infrastructure errors.
6. Returns the Step 4 normalized signature array.

If the script exits non-zero, report its JSON error and do not continue to threshold analysis unless at least two valid signatures are available from another trusted source.

Step 3: Artifact Classification Rules

The classifier follows these rules:

• TEST_FAILURE when artifacts contain openshift-e2e-test/, e2e-*, junit/, junit XML files, openshift-tests-*, or monitor-test-*.
• INFRA_FAILURE only when artifacts show setup/build/gather output without test artifacts, or artifacts are empty/unavailable after a valid job fetch.
• MonitorTest failures count as test failures because MonitorTests run during e2e execution.
• Classification must be artifact-based. Do not classify from Prow descriptions or error messages alone.

Step 4: Use Normalized Failure Signatures

Use the script output directly as the normalized signature array.

For test failures:

{
  "type": "test_failure",
  "url": "job_url",
  "tests": ["failing_test_name1", "failing_test_name2"],
  "test_count": 2
}

For infrastructure failures:

{
  "type": "infra_failure",
  "url": "job_url",
  "error": "normalized_error_message",
  "error_hash": "md5_of_error_message"
}

Step 5: Compare Signatures for Permafail Pattern

Apply permafail detection logic using failure-type-based thresholds - the denominator is the count of comparable runs (same failure type), not the matching group size:

Detection Thresholds (based on comparable run count):

• 2-3 comparable runs: All must match (100% match required)
• 4-5 comparable runs: At least 4 must match (80% match required)
• 6-10 comparable runs: At least ceil(count × 0.7) must match (70% threshold)

For Test Failures:

1. Count total test_failure signatures (this is the denominator)
2. Extract all unique test names from test_failure signatures
3. For each unique test name, count how many test_failure signatures contain it (this is the numerator)
4. Apply threshold based on the denominator (total test_failure count):
   • If denominator is 2-3: numerator must equal denominator (100%)
   • If denominator is 4-5: numerator must be ≥4 (80%)
   • If denominator is 6-10: numerator must be ≥ceil(denominator × 0.7) (70%)
5. If ANY test name meets its threshold: PERMAFAIL = TRUE
   • Report which test(s) met the threshold and their occurrence count
6. If no test meets the threshold: PERMAFAIL = FALSE

Example: 8 test_failure signatures, "TestNetworkPolicy" appears in 6 → 6/8 = 75% → needs ceil(8×0.7)=6 → 6≥6 ✓ PERMAFAIL

For Infrastructure Failures:

1. Count total infra_failure signatures (this is the denominator)
2. Extract error messages and group similar errors (exact match or >70% character similarity using normalized Levenshtein: similarity = 1 - (levenshtein_distance(a, b) / max(len(a), len(b))). Treat two normalized errors as similar when similarity > 0.70. If both strings are empty, do not group them as similar; require a non-empty normalized error.)
3. For each error group, count how many infra_failure signatures contain it (this is the numerator)
4. Apply threshold based on the denominator (total infra_failure count):
   • If denominator is 2-3: numerator must equal denominator (100%)
   • If denominator is 4-5: numerator must be ≥4 (80%)
   • If denominator is 6-10: numerator must be ≥ceil(denominator × 0.7) (70%)
5. If ANY error group meets its threshold: PERMAFAIL = TRUE
   • Report the error message and occurrence count
6. If no error group meets the threshold: PERMAFAIL = FALSE

Example: 5 infra_failure signatures - 3 have "operator X timeout", 2 have random errors → 3/5 = 60% → needs 4/5 (80%) → 3<4 → NOT PERMAFAIL

For Mixed Failure Types:

1. Separate signatures by type (test_failure vs infra_failure)
2. For each type, count total signatures (the denominator for that type)
3. Apply threshold logic to each type independently:
   • Test failures: If ≥2 test_failure signatures exist, check if any test appears frequently enough to meet the threshold based on test_failure count
   • Infra failures: If ≥2 infra_failure signatures exist, check if any error appears frequently enough to meet the threshold based on infra_failure count
4. Minimum runs requirement: Need at least 2 runs of the same type to establish a permafail pattern. A single failure of either type is insufficient.
5. If either type meets the threshold AND has ≥2 runs: PERMAFAIL = TRUE
   • Report the dominant pattern (the one that triggered permafail)
   • Explain which runs contributed and which were ignored (e.g., "All 4 runs that reached e2e tests failed on TestNetworkPolicy. 3 other runs failed during cluster setup and are not relevant to this test failure pattern.")
6. If neither type meets criteria: PERMAFAIL = FALSE

Example Scenario 1: PERMAFAIL (4 test, 3 infra):

• 7 total runs provided
• 3 runs: infra_failure (cluster creation failed)
• 4 runs: test_failure (all failing on TestNetworkPolicy)

Analysis:

• Test failures: 4 runs → use 4/5 threshold (80%) → need 4 matching → have 4/4 (100%) ✓ PERMAFAIL
• Infra failures: 3 runs → use 3/3 threshold (100%) → different errors → NOT permafail
• Verdict: PERMAFAIL = TRUE (test failure group met criteria)
• Reason: "All 4 runs that reached e2e tests failed on TestNetworkPolicy (100% match). 3 additional runs failed during infrastructure setup and are not relevant to this test failure pattern."

Example Scenario 2: NOT PERMAFAIL (1 test, 6 diverse infra):

• 7 total runs provided
• 6 runs: infra_failure (each with different errors: cluster creation timeout, AWS quota, network issue, pod eviction, storage failure, DNS timeout)
• 1 run: test_failure (failed on TestNetworkPolicy)

Analysis:

• Test failures: 1 run → INSUFFICIENT (need minimum 2 runs to establish pattern)
• Infra failures: 6 runs with all different errors → no single error appears ≥5 times → NOT permafail
• Verdict: PERMAFAIL = FALSE
• Reason: "Only 1 out of 7 runs reached e2e tests and failed on '[sig-arch] daemonset cni-sysctl-allowlist-ds maxUnavailable requirement'. The other 6 runs failed during infrastructure setup, each with different unrelated issues (no consistent infra pattern). A single test failure is insufficient to establish a permafail pattern - we need multiple runs with consistent failures to confirm systematic breakage."

Step 6: Generate Verdict and Return JSON

Construct the final response object with:

• Boolean verdict: permafail (true/false)
• Reason string explaining the determination. Always include explicit slash-format ratios for the dominant pattern and strongest non-matching pattern, such as 7/10, 4/4, 5/6, or 2/10. Do not write only 7 of 10; include 7/10.
• Complete failure signatures array
• Common tests array (if applicable and permafail=true)
• Confidence score as a JSON number from 0.0 to 1.0, representing confidence in the final verdict, not the raw match ratio. Never use strings such as "high", "medium", or "0.95". For example, a clearly non-permafail 2/10 pattern can still have confidence around 0.70 because the verdict is well supported.
• Stable failure_type value:
  • test_failure when the final verdict is driven by test-failure analysis, or only test failures are present
  • infra_failure when the final verdict is driven by infrastructure-failure analysis, or only infrastructure failures are present
  • mixed when both test and infrastructure failures are present and no single type meets the permafail threshold
• match_ratio: Slash-format string for the dominant pattern, such as "7/10", "4/4", "5/6", or "2/10".
• threshold_required: Integer count required for the comparable-run group to qualify as permafail.
• matching_runs: Integer numerator for the dominant or strongest pattern.
• comparable_runs: Integer denominator for the comparable-run group.

The final JSON must be machine-checkable. The ratio-bearing fields must be top-level fields, not nested under an analysis object. Use this exact style:

{
  "permafail": true,
  "confidence": 0.95,
  "reason": "7/10 test_failure runs failed TestNetworkPolicy, meeting the required 7/10 threshold.",
  "failure_type": "test_failure",
  "match_ratio": "7/10",
  "matching_runs": 7,
  "comparable_runs": 10,
  "threshold_required": 7,
  "signatures": []
}

For a mixed non-permafail, use failure_type: "mixed" and include the word insufficient in the reason when one failure type has fewer than 2 comparable runs.

Do not set confidence equal to the match percentage. Confidence means confidence in the verdict:

• Clear non-permafail with complete data and a strongest pattern below threshold, such as 2/10, should use confidence: 0.70 or higher.
• Exact threshold permafail, such as 7/10 test failures or 5/6 infra failures, should use confidence: 0.85 or higher.
• All comparable runs matching, such as 4/4, should use confidence: 0.99.
• Ambiguous or incomplete data should use lower confidence.

Output Format

The skill returns a JSON object with this schema:

{
  "permafail": true,
  "confidence": 0.95,
  "reason": "3/3 test_failure runs show the same failing test 'test_node_scale' - consistent permanent failure",
  "failure_type": "test_failure",
  "match_ratio": "3/3",
  "matching_runs": 3,
  "comparable_runs": 3,
  "threshold_required": 3,
  "signatures": [
    {
      "type": "test_failure",
      "url": "https://prow.ci.openshift.org/view/gs/bucket/logs/...",
      "tests": ["test_node_scale"],
      "test_count": 1
    },
    {
      "type": "test_failure",
      "url": "https://prow.ci.openshift.org/view/gs/bucket/logs/...",
      "tests": ["test_node_scale"],
      "test_count": 1
    },
    {
      "type": "test_failure",
      "url": "https://prow.ci.openshift.org/view/gs/bucket/logs/...",
      "tests": ["test_node_scale"],
      "test_count": 1
    }
  ],
  "common_tests": ["test_node_scale"]
}

For Infrastructure Failure (permafail=true)

{
  "permafail": true,
  "confidence": 0.92,
  "reason": "All 3 runs fail at cluster creation with identical error: 'Insufficient quota for machine type n1-standard-4'",
  "failure_type": "infra_failure",
  "signatures": [
    {
      "type": "infra_failure",
      "url": "https://prow.ci.openshift.org/view/gs/bucket/logs/...",
      "error": "Insufficient quota for machine type n1-standard-4",
      "error_hash": "a1b2c3d4e5f6g7h8"
    },
    {
      "type": "infra_failure",
      "url": "https://prow.ci.openshift.org/view/gs/bucket/logs/...",
      "error": "Insufficient quota for machine type n1-standard-4",
      "error_hash": "a1b2c3d4e5f6g7h8"
    },
    {
      "type": "infra_failure",
      "url": "https://prow.ci.openshift.org/view/gs/bucket/logs/...",
      "error": "Insufficient quota for machine type n1-standard-4",
      "error_hash": "a1b2c3d4e5f6g7h8"
    }
  ]
}

For Non-Permafail (mixed or varying failures)

{
  "permafail": false,
  "confidence": 0.88,
  "reason": "Mixed failure types detected: 2/3 runs are test_failure, 1/3 is infra_failure. Inconsistent pattern indicates flaky behavior, not a systematic permafail. Test failures: 2/3 (threshold: 2/3). Infra failures: 1/3 (threshold: 1/3).",
  "failure_type": "mixed",
  "match_ratio": "2/3",
  "matching_runs": 2,
  "comparable_runs": 3,
  "threshold_required": 2,
  "signatures": [
    {
      "type": "test_failure",
      "url": "...",
      "tests": ["test_networking"],
      "test_count": 1
    },
    {
      "type": "infra_failure",
      "url": "...",
      "error": "Pod evicted due to memory pressure",
      "error_hash": "x1y2z3a4b5c6d7e8"
    },
    {
      "type": "test_failure",
      "url": "...",
      "tests": ["test_storage", "test_deployment"],
      "test_count": 2
    }
  ]
}

Failure Signature Format

Test Failure Signature

{
  "type": "test_failure",
  "url": "string (job URL)",
  "tests": ["array", "of", "failing_test_names"],
  "test_count": "integer (length of tests array)"
}

Fields:

• type: Always "test_failure"
• url: The Prow job URL for this run
• tests: Array of test names extracted from failure logs (deduplicated)
• test_count: Count of unique failing tests

Infrastructure Failure Signature

{
  "type": "infra_failure",
  "url": "string (job URL)",
  "error": "string (normalized error message)",
  "error_hash": "string (MD5 hash of normalized error)"
}

Fields:

• type: Always "infra_failure"
• url: The Prow job URL for this run
• error: Normalized error message with timestamps and build IDs removed
• error_hash: MD5 hash for fast similarity comparison

Permafail Detection Logic

Test Failure Logic

Apply the threshold rules from Step 5 based on the number of test_failure signatures (the comparable run count):

1. Count total test_failure signatures (this is N, the denominator)
2. Collect all unique test names from test_failure signatures
3. For each unique test name, count how many test_failure signatures contain it (the numerator)
4. Check if any test meets the threshold:
   • N=2-3: Test must appear in ALL N runs (100% match required)
   • N=4-5: Test must appear in ≥4 runs (80% match required)
   • N=6-10: Test must appear in ≥ceil(N × 0.7) runs (70% match required)
5. Permafail = TRUE if ANY test meets the threshold
6. Set confidence based on match strength:
   • 0.99 if all test_failure runs have identical test set
   • 0.85 or higher if threshold is met exactly (e.g., 3/3, 4/5, 7/10)
   • 0.92 if threshold is exceeded (e.g., 5/5, 8/10)
   • 0.70 or higher if no test meets threshold but the non-permafail verdict is clear
7. In the reason, include the strongest test ratio in slash form, for example 7/10 test_failure runs failed TestNetworkPolicy or 2/10 test_failure runs failed TestNetworkPolicy.
8. Include top-level match_ratio, matching_runs, comparable_runs, and threshold_required fields for the strongest test pattern.

Infrastructure Failure Logic

Apply the threshold rules from Step 5 based on the number of infra_failure signatures (the comparable run count):

1. Count total infra_failure signatures (this is N, the denominator)
2. Extract error messages and group similar errors (exact hash match or >70% string similarity)
3. For each error group, count how many infra_failure signatures contain it (the numerator)
4. Apply threshold based on N (total infra_failure count, not the error group size):
   • N=2-3: Error must appear in ALL N runs (100% required)
   • N=4-5: Error must appear in ≥4 runs (80% required)
   • N=6-10: Error must appear in ≥ceil(N × 0.7) runs (70% required)
5. Permafail = TRUE if ANY error group meets its threshold
   • Example: 5 total infra_failure signatures, 3 with "operator X timeout", 2 with random errors
   • Denominator N=5 → needs 4/5 (80%) → 3/5 = 60% < 80% → NOT PERMAFAIL
6. Set confidence based on match strength:
   • 0.99 if all infra_failure runs have identical error hash
   • 0.85 or higher if the threshold is met exactly
   • 0.92 if threshold is met with >80% string similarity
   • 0.88 if threshold is met with >70% string similarity
   • 0.70 or higher if no error group meets threshold but the non-permafail verdict is clear
7. In the reason, include the strongest infra ratio in slash form, for example 5/6 infra_failure runs share operator authentication timeout or 1/6 infra_failure runs share the strongest error.
8. Include top-level match_ratio, matching_runs, comparable_runs, and threshold_required fields for the strongest infra pattern.

Mixed Type Logic

When both test_failure and infra_failure types are present:

1. Analyze each group independently using their respective thresholds
2. Test failures: Check if test_failure signatures have common failing tests
3. Infra failures: Check if infra_failure signatures have common errors
4. If either group meets the permafail criteria: PERMAFAIL = TRUE
   • Report the pattern that triggered permafail (tests or infra)
   • Explain the breakdown (e.g., "4 of 4 test runs failed on the same test; 3 other runs failed during setup")
   • Set failure_type to the type that triggered the permafail: test_failure or infra_failure
   • Use the triggering type's top-level ratio fields. For example, if 4/4 test failures match and infra failures are noise, set failure_type: "test_failure", match_ratio: "4/4", matching_runs: 4, comparable_runs: 4, and the test threshold.
5. If neither group meets criteria: PERMAFAIL = FALSE
   • Reason: "No consistent pattern found in test failures or infrastructure failures"
   • If both test_failure and infra_failure signatures are present, set failure_type to mixed, not flaky
6. In mixed cases, include slash-format ratios for the evaluated groups in the reason, such as 1/1 test_failure runs and 1/6 infra_failure runs.

Key Principle: Infrastructure failures (cluster setup, resource quota, network issues) are orthogonal to test failures. A PR can have a systematic test failure (permafail) even if some runs fail during infrastructure setup. Analyze each type separately and detect permafails in either category.

Error Handling

Scenario 1: Artifact Fetch Failure

If artifact fetching fails for a job URL:

• Return status: "error"
• Return error message with specific failure reason (network error, 404, timeout, etc.)
• Continue with remaining jobs when at least 2 jobs have not yet been attempted
• Do NOT return a permafail verdict when fewer than 2 jobs completed successfully

Response:

{
  "status": "error",
  "error": "Failed to fetch artifacts for job: 404 Not Found at gcsweb URL",
  "action": "verify_job_url_validity"
}

Scenario 2: Timeout on Job Analysis

If the classifier script times out or returns an incomplete result:

• Report the script error.
• Continue only if at least 2 valid signatures are available from another trusted source.
• If only 1 or 0 signatures are available: Return error.

Response:

{
  "status": "error",
  "error": "Analysis timeout: Only 2 of 3 jobs analyzed successfully. Insufficient data for permafail determination.",
  "completed_jobs": 2,
  "action": "retry_with_single_job"
}

Scenario 3: Invalid Job URLs

If URL validation fails:

• Return status: "error"
• Return specific validation error message
• Do NOT attempt analysis

Response:

{
  "status": "error",
  "error": "Invalid job URL format: 'url3' is not a valid Prow job URL",
  "invalid_url": "url3",
  "action": "provide_valid_urls"
}

Scenario 4: Job Names Don't Match

If the job_name parameter doesn't match the actual job names extracted from URLs:

• Return status: "error"
• Return the expected vs actual job names

Response:

{
  "status": "error",
  "error": "Job name mismatch. Expected 'pull-ci-job-xyz' but found 'pull-ci-job-abc' in run 2",
  "expected_job": "pull-ci-job-xyz",
  "actual_job": "pull-ci-job-abc",
  "action": "provide_matching_job_urls"
}

Scenario 5: Insufficient Comparable Runs (Different Types)

If analysis completes but there are insufficient comparable runs for permafail determination (e.g., 1 test_failure + 1 infra_failure):

• Return permafail: false
• Explain that neither failure type has ≥2 comparable runs
• This is NOT an error - the analysis succeeded but found no same-type pattern

Response:

{
  "permafail": false,
  "confidence": 0.70,
  "reason": "Insufficient comparable runs: 1/2 test failures, 1/2 infra failures. Cannot establish a permafail pattern with only one run of each type. Need at least 2 runs of the same failure type to determine if failures are systematic. Test: 1/2 (threshold: 2/2). Infra: 1/2 (threshold: 2/2).",
  "failure_type": "mixed",
  "match_ratio": "1/2",
  "matching_runs": 1,
  "comparable_runs": 2,
  "threshold_required": 2,
  "signatures": [
    {
      "type": "test_failure",
      "url": "...",
      "tests": ["[sig-network] test"]
    },
    {
      "type": "infra_failure",
      "url": "...",
      "error": "cluster creation failed"
    }
  ]
}

Scenario 6: Failure to Extract Failure Details

If the classifier output doesn't contain expected failure information:

• Mark this run as "incomplete"
• Continue with other runs
• If ≥2 runs have valid failure data, proceed with analysis
• Otherwise, return error

Response:

{
  "status": "incomplete",
  "warning": "Run 1 analysis incomplete: could not extract failure details",
  "completed_jobs": 2,
  "incomplete_jobs": 1,
  "permafail": "unknown",
  "recommendation": "Review job logs manually or retry analysis"
}

Examples

Example 1: Permafail - Identical Failing Test

Input:

{
  "failure_urls": [
    "https://prow.ci.openshift.org/view/gs/..../logs/pull-ci-openshift-origin-master-e2e-aws/1234567",
    "https://prow.ci.openshift.org/view/gs/..../logs/pull-ci-openshift-origin-master-e2e-aws/1234568",
    "https://prow.ci.openshift.org/view/gs/..../logs/pull-ci-openshift-origin-master-e2e-aws/1234569"
  ],
  "job_name": "pull-ci-openshift-origin-master-e2e-aws",
  "pr_info": {
    "pr_number": 12345,
    "repository": "openshift/origin"
  }
}

Subagent analysis results for all 3 runs:

• Run 1: Failed tests = ["[sig-api] API discovery should provide capability information"]
• Run 2: Failed tests = ["[sig-api] API discovery should provide capability information"]
• Run 3: Failed tests = ["[sig-api] API discovery should provide capability information"]

Output:

{
  "permafail": true,
  "confidence": 0.99,
  "reason": "3/3 consecutive runs fail with identical test: '[sig-api] API discovery should provide capability information'. This is a systematic permanent failure.",
  "failure_type": "test_failure",
  "match_ratio": "3/3",
  "matching_runs": 3,
  "comparable_runs": 3,
  "threshold_required": 3,
  "signatures": [
    {
      "type": "test_failure",
      "url": "https://prow.ci.openshift.org/view/gs/..../logs/pull-ci-openshift-origin-master-e2e-aws/1234567",
      "tests": ["[sig-api] API discovery should provide capability information"],
      "test_count": 1
    },
    {
      "type": "test_failure",
      "url": "https://prow.ci.openshift.org/view/gs/..../logs/pull-ci-openshift-origin-master-e2e-aws/1234568",
      "tests": ["[sig-api] API discovery should provide capability information"],
      "test_count": 1
    },
    {
      "type": "test_failure",
      "url": "https://prow.ci.openshift.org/view/gs/..../logs/pull-ci-openshift-origin-master-e2e-aws/1234569",
      "tests": ["[sig-api] API discovery should provide capability information"],
      "test_count": 1
    }
  ],
  "common_tests": ["[sig-api] API discovery should provide capability information"]
}

Example 2: Permafail Despite Mixed Failure Types

Input:

{
  "failure_urls": [
    "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1111",
    "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1112",
    "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1113",
    "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1114",
    "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1115",
    "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1116",
    "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1117"
  ],
  "job_name": "periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node",
  "pr_info": {
    "pr_number": 3186,
    "repository": "openshift/ovn-kubernetes"
  }
}

Subagent analysis results:

• Run 1: Infrastructure failure = "Cluster creation timeout" (infra_failure)
• Run 2: Failed tests = ["[sig-network] Networking should provide connectivity"] (test_failure)
• Run 3: Infrastructure failure = "AWS quota exceeded" (infra_failure)
• Run 4: Failed tests = ["[sig-network] Networking should provide connectivity"] (test_failure)
• Run 5: Failed tests = ["[sig-network] Networking should provide connectivity"] (test_failure)
• Run 6: Infrastructure failure = "Cluster creation timeout" (infra_failure)
• Run 7: Failed tests = ["[sig-network] Networking should provide connectivity"] (test_failure)

Analysis:

• 7 total runs: 3 infra_failures, 4 test_failures
• Test failures: 4/4 (100%) have identical failing test
• Infra failures: 3 runs, but different errors (not a permafail pattern in infra)
• Verdict: PERMAFAIL = TRUE based on test failure group

Output:

{
  "permafail": true,
  "confidence": 0.99,
  "reason": "All 4 runs that reached e2e tests failed on '[sig-network] Networking should provide connectivity' (100% match). 3 additional runs failed during infrastructure setup (cluster creation, AWS quota) and are not relevant to this test failure pattern. This is a systematic test failure caused by the PR changes.",
  "failure_type": "test_failure",
  "signatures": [
    {
      "type": "infra_failure",
      "url": "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1111",
      "error": "Cluster creation timeout",
      "error_hash": "a1b2c3d4"
    },
    {
      "type": "test_failure",
      "url": "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1112",
      "tests": ["[sig-network] Networking should provide connectivity"],
      "test_count": 1
    },
    {
      "type": "infra_failure",
      "url": "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1113",
      "error": "AWS quota exceeded",
      "error_hash": "e5f6g7h8"
    },
    {
      "type": "test_failure",
      "url": "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1114",
      "tests": ["[sig-network] Networking should provide connectivity"],
      "test_count": 1
    },
    {
      "type": "test_failure",
      "url": "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1115",
      "tests": ["[sig-network] Networking should provide connectivity"],
      "test_count": 1
    },
    {
      "type": "infra_failure",
      "url": "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1116",
      "error": "Cluster creation timeout",
      "error_hash": "a1b2c3d4"
    },
    {
      "type": "test_failure",
      "url": "https://prow.ci.openshift.org/view/gs/..../logs/periodic-ci-openshift-release-main-ci-4.19-e2e-aws-upgrade-ovn-single-node/1117",
      "tests": ["[sig-network] Networking should provide connectivity"],
      "test_count": 1
    }
  ],
  "common_tests": ["[sig-network] Networking should provide connectivity"]
}

Example 3: NOT Permafail - Insufficient Matching Infra Errors

Input: 5 runs where 3 have identical operator installation failure, 2 have random infra issues

Subagent analysis results:

• Run 1: Infrastructure failure = "operator authentication timeout waiting for operator to reach Available=True" (infra_failure)
• Run 2: Infrastructure failure = "AWS quota exceeded for instance type m5.xlarge" (infra_failure)
• Run 3: Infrastructure failure = "operator authentication timeout waiting for operator to reach Available=True" (infra_failure)
• Run 4: Infrastructure failure = "operator authentication timeout waiting for operator to reach Available=True" (infra_failure)
• Run 5: Infrastructure failure = "Pod evicted due to memory pressure on node ip-10-0-1-2" (infra_failure)

Analysis:

• 5 total infra_failure signatures (denominator = 5)
• "operator authentication timeout" appears in 3 runs (numerator = 3)
• Threshold for N=5 (4-5 runs): need at least 4 matching (80% required)
• 3/5 = 60% < 80% → NOT PERMAFAIL

Output:

{
  "permafail": false,
  "confidence": 0.70,
  "reason": "Infrastructure failures are not consistent enough. 3/5 runs failed with 'operator authentication timeout waiting for operator to reach Available=True' (60% match), but with 5 infra failures at least 4/5 must match (80% required). The presence of 2 different random errors indicates flaky infrastructure rather than systematic failure.",
  "failure_type": "infra_failure",
  "match_ratio": "3/5",
  "matching_runs": 3,
  "comparable_runs": 5,
  "threshold_required": 4,
  "signatures": [
    {
      "type": "infra_failure",
      "url": "...",
      "error": "operator authentication timeout waiting for operator to reach Available=True",
      "error_hash": "a1b2c3d4"
    },
    {
      "type": "infra_failure",
      "url": "...",
      "error": "AWS quota exceeded for instance type m5.xlarge",
      "error_hash": "e5f6g7h8"
    },
    {
      "type": "infra_failure",
      "url": "...",
      "error": "operator authentication timeout waiting for operator to reach Available=True",
      "error_hash": "a1b2c3d4"
    },
    {
      "type": "infra_failure",
      "url": "...",
      "error": "operator authentication timeout waiting for operator to reach Available=True",
      "error_hash": "a1b2c3d4"
    },
    {
      "type": "infra_failure",
      "url": "...",
      "error": "Pod evicted due to memory pressure on node ip-10-0-1-2",
      "error_hash": "i9j0k1l2"
    }
  ]
}

Example 4: Non-Permafail - No Consistent Pattern

Input: 3 runs with different test failures

Subagent analysis results:

• Run 1: Failed tests = ["[sig-network] networking should support networking"] (test_failure)
• Run 2: Failed tests = ["[sig-storage] storage should support volumes"] (test_failure)
• Run 3: Failed tests = ["[sig-api] API discovery should work"] (test_failure)

Output:

{
  "permafail": false,
  "confidence": 0.70,
  "reason": "No consistent failure pattern detected. 0/3 runs show matching tests - each of the 3 runs failed with different tests: networking, storage, API discovery. This indicates flaky/non-deterministic behavior rather than a systematic permafail.",
  "failure_type": "test_failure",
  "match_ratio": "0/3",
  "matching_runs": 0,
  "comparable_runs": 3,
  "threshold_required": 3,
  "signatures": [
    {
      "type": "test_failure",
      "url": "...",
      "tests": ["[sig-network] networking should support networking"],
      "test_count": 1
    },
    {
      "type": "test_failure",
      "url": "...",
      "tests": ["[sig-storage] storage should support volumes"],
      "test_count": 1
    },
    {
      "type": "test_failure",
      "url": "...",
      "tests": ["[sig-api] API discovery should work"],
      "test_count": 1
    }
  ]
}

Threshold Logic Validation Examples

Table-driven test cases demonstrating correct threshold behavior:

Technical Details

Artifact Analysis Approach

This skill analyzes Prow job artifacts directly using techniques from existing CI skills:

1. URL parsing - Extract job name and build ID from Prow URLs
2. Artifact fetching - Use plugins/ci/scripts/classify-job-failures.py to fetch prowjob.json and browse artifacts
3. Classification - Use artifact-based detection (junit files, test directories) to classify failures
4. Failure extraction - Parse junit XML or build logs to extract test names or error messages

This approach follows patterns from fetch-prowjob-json, prow-job-artifact-search, and prow-job-analyze-test-failure skills.

Script Execution Strategy

The classifier script performs deterministic artifact analysis before AI threshold reasoning:

failure_urls ━━━ classify-job-failures.py ━━━ normalized signatures ━━━ Step 5 threshold analysis

Benefits:

• Keeps artifact fetching and parsing deterministic.
• Avoids spending agent reasoning on mechanical classification.
• Produces the same normalized signature schema used by offline eval cases.

Synchronization:

• Run the script once with all failure URLs.
• Require at least 2 valid normalized signatures to proceed.
• Stop and report the script's JSON error if URL validation or artifact fetching fails.

Error Message Normalization

Normalize infrastructure error messages for comparison:

1. Remove timestamps: 2025-05-12T14:32:10Z → ""
2. Remove build IDs: build-12345-xyz → ""
3. Remove resource names with IDs: pod-abc123xyz → "pod-*"
4. Remove request/limit values: Numbers in memory/CPU specs → ""
5. Keep: Error classification, core message, error type

Example normalization:

Input:  "Pod evicted at 2025-05-12T14:32:10Z (build-12345): insufficient memory (512M < 1Gi required)"
Output: "Pod evicted: insufficient memory (* < *Gi required)"

Confidence Scoring

Confidence reflects how certain the permafail verdict is:

• 0.99: All 3 runs have identical failure signature (test names or error hashes)
• 0.95: All 3 runs have ≥1 common failing test in test_failure
• 0.92: All 3 runs have >80% similar error messages in infra_failure
• 0.85: 2 of 3 runs share common failure or mixed types detected
• 0.70: Insufficient data or ambiguous failure patterns

Use confidence to determine remediation priority:

• Confidence ≥ 0.95: High priority permafail, block PR merge
• Confidence 0.85-0.94: Medium priority, warn but allow manual override
• Confidence < 0.85: Low confidence verdict, require manual review