{ "meta": { "provider": "gemini", "model": "gemini-3.6-flash", "version": "1.2.8", "commit": "b6de6e1", "date": "2026-10-26 to 2026-10-28 (one round a day, free Gemini quota)", "rounds": 3 }, "summary": { "held_out": { "runs": 33, "incidents": 30, "root_cause": 30, "strict": 30, "lenient": 30, "commit_expected": 18, "commit_correct": 18, "distractor_blamed": 0, "healthy": 3, "healthy_silent": 3, "mean_alerting": 1.0, "errors": 0, "cost_usd": 0.0227, "mean_seconds": 30.5 }, "all": { "runs": 33, "incidents": 30, "root_cause": 30, "strict": 30, "lenient": 30, "commit_expected": 18, "commit_correct": 18, "distractor_blamed": 0, "healthy": 3, "healthy_silent": 3, "mean_alerting": 1.0, "errors": 0, "cost_usd": 0.0227, "mean_seconds": 30.5 }, "consistency": { "scenarios": 11, "stable": 11 } }, "results": [ { "id": "h01_connection_leak", "set": "held_out", "category": "bad deploy", "name": "Connection leak on an error path (pool size unchanged)", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 25.5, "cost_usd": 0.000752, "tokens_input": 5315, "tokens_output": 1179, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "inventory-api", "affected_services": [], "description": "SQLAlchemy QueuePool limit of 40 overflow 0 reached, causing connection timeouts during inventory reservation requests due to a connection leak.", "root_cause": "Commit 4b0e77d1 in `inventory/stock.py` replaced the `with self.db.session() as s:` context manager with manual session management. When `row.available < qty` raises an `OutOfStock` exception, execution exits before `s.close()` is reached, leaking database sessions until the QueuePool limit of 40 connections is exhausted.", "recommendation": "Refactor `StockService.reserve` in `inventory/stock.py` to restore context manager usage (`with self.db.session() as s:`) or wrap session handling in a `try...finally` block so `s.close()` is always executed even when `OutOfStock` is raised.", "linked_commits": [ { "sha": "4b0e77d1", "provider": "unknown", "project_id": null } ], "reasoning": "1. Observed repeating sqlalchemy.exc.TimeoutError logs in inventory-api indicating QueuePool limit of 40 was reached.\n2. Checked recent commits and found commit 4b0e77d1 modifying line 57 of inventory/stock.py, which removed the context manager for session handling.\n3. Confirmed that raising OutOfStock(sku) circumvents s.close(), causing a connection leak on every out-of-stock reservation attempt." } ], "answer": { "services": [ "inventory-api" ], "cause": [ [ "leak", "not closed", "never closed", "stays open", "left open", "not released", "never released", "not returned", "close" ] ], "blame_sha": "4b0e77d1", "wrong_shas": [ "9c1d2e3f" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "not blamed 9c1d2e3": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h02_retry_storm", "set": "held_out", "category": "bad deploy", "name": "Retry storm from a client change overloads a healthy service", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 36.9, "cost_usd": 0.00077, "tokens_input": 4317, "tokens_output": 1489, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "product-page", "affected_services": [ "ratings-svc" ], "description": "Commit e5a91b02 in product-page changed the ratings client retry configuration to 10 attempts with 0ms delay. This triggered an unmitigated retry storm when requests failed, overloading ratings-svc, pushing its CPU to 99%, filling its request queue (1024 waiting), and generating 503 errors.", "root_cause": "Commit e5a91b02 updated web/src/clients/ratings.ts in product-page, replacing 3 retries with exponential backoff and jitter with 10 retries with 0ms fixed delay. Under load or transient errors, product-page immediately bombards ratings-svc with 10 zero-delay retry attempts, saturating ratings-svc's request queue and causing severe CPU spikes and HTTP 503 failures.", "recommendation": "Revert commit e5a91b02 to restore exponential backoff with jitter (e.g. initialMs: 200, maxMs: 5000, jitter: true) and limit max attempts to 3.", "linked_commits": [ { "sha": "e5a91b02", "provider": "unknown", "project_id": null } ], "reasoning": "1. Observed warnings in product-page showing up to 10 retries per failed ratings request alongside ratings-svc request queue saturation logs.\n2. Checked commit e5a91b02 deployed at 14:26:00Z and identified that backoff delay was set to 0ms and retry attempts increased from 3 to 10 in web/src/clients/ratings.ts.\n3. Correlated the commit timestamp (14:26:00Z) with the onset of product-page retries (14:30:00Z), 2600 span errors, and ratings-svc CPU peaking at 99%.\n4. Confirmed that removing backoff and jitter created a classic retry storm that overwhelmed the downstream service." } ], "answer": { "services": [ "product-page" ], "cause": [ [ "retry", "retries", "retrying" ], [ "backoff", "back-off", "storm", "amplif", "10 attempts", "attempts", "delay" ] ], "blame_sha": "e5a91b02", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h03_kafka_rebalance", "set": "held_out", "category": "config", "name": "Kafka consumer rebalance loop after a poll-size change", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 133.0, "cost_usd": 0.000802, "tokens_input": 4398, "tokens_output": 1575, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "order-events-consumer", "affected_services": [], "description": "Kafka consumer order-events-consumer is experiencing repeated poll timeouts (max.poll.interval.ms exceeded) leading to CommitFailedException and continuous consumer group rebalancing.", "root_cause": "Commit 71f0c3aa increased max-poll-records tenfold from 500 to 5000 in consumer/src/main/resources/application.yaml without increasing max.poll.interval.ms (300000ms). Processing 5000 records in a single batch takes longer than 5 minutes, causing Kafka to mark the consumer as dead, trigger consumer group rebalances, and fail offset commits with CommitFailedException.", "recommendation": "Revert max-poll-records back to 500 or tune it to a lower value (e.g., 1000) that can be fully processed within 300,000 ms, or increase max.poll.interval.ms to accommodate the batch size.", "linked_commits": [ { "sha": "71f0c3aa", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed cyclic poll timeout warnings followed by CommitFailedException errors in the logs for order-events-consumer starting at 14:22:00.\n2. I inspected recent code changes and found commit 71f0c3aa deployed at 14:15:00 which increased max-poll-records from 500 to 5000 while leaving max.poll.interval.ms at 300000ms.\n3. I confirmed that the tenfold increase in records polled per loop caused message processing time to exceed the 5-minute poll interval, triggering repeated rebalances and commit failures." } ], "answer": { "services": [ "order-events-consumer" ], "cause": [ [ "poll", "max-poll-records", "max.poll" ], [ "5000", "records", "rebalanc", "interval", "processing time" ] ], "blame_sha": "71f0c3aa", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h04_clock_skew", "set": "held_out", "category": "infrastructure", "name": "Clock skew on one node rejects valid tokens", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 24.0, "cost_usd": 0.000614, "tokens_input": 4153, "tokens_output": 1010, "issues": [ { "severity": "WARNING", "confidence": "HIGH", "component": "auth-gateway", "affected_services": [], "description": "auth-gateway is failing JWT verification with 'token used before issued' errors because the issued-at time (iat) is ahead of the local system clock (now).", "root_cause": "Clock skew between the token issuance server and auth-gateway causes incoming JWT 'iat' claims to appear in the future relative to auth-gateway's local system clock.", "recommendation": "Resynchronize system time using NTP across all hosts/containers and configure a clock skew tolerance (e.g. 5-30 seconds leeway) in the JWT validation logic.", "linked_commits": [], "reasoning": "1. I observed repeated ERROR log entries in auth-gateway reporting 'JWT rejected: token used before issued'.\n2. I recognized that 'iat' being greater than 'now' indicates a system clock desynchronization between the identity provider/issuer and auth-gateway.\n3. I reviewed recent code commits and confirmed 2aa7d19c only added a logging import, ruling out application code logic changes and pointing directly to infrastructure clock drift." } ], "answer": { "services": [ "node-c", "chronyd", "auth-gateway" ], "cause": [ [ "clock", "time sync", "ntp", "chrony", "skew", "drift" ] ], "blame_sha": null, "wrong_shas": [ "2aa7d19c" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "not blamed 2aa7d19": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h05_hpa_cap", "set": "held_out", "category": "config", "name": "Autoscaler capped at 2 replicas during a traffic spike", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 34.9, "cost_usd": 0.000756, "tokens_input": 4524, "tokens_output": 1389, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "search-api", "affected_services": [ "ingress-nginx" ], "description": "search-api experienced severe CPU saturation (99% current, 100% peak) and request latency up to 30,000ms, causing persistent upstream connection timeouts in ingress-nginx for /search requests.", "root_cause": "Commit d3c4b5a6 updated deploy/k8s/search-api-hpa.yaml to reduce maxReplicas from 20 to 2. Capping the HPA autoscaling at 2 replicas prevented search-api from scaling horizontally under traffic load, leading to CPU exhaustion (100% peak) and 30s span timeouts that cascaded to HTTP 110 upstream connection timeouts at ingress-nginx.", "recommendation": "Increase maxReplicas in deploy/k8s/search-api-hpa.yaml back to a higher capacity threshold (e.g., 20) to allow search-api to scale out when traffic increases.", "linked_commits": [ { "sha": "d3c4b5a6", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed persistent 110 Connection timed out errors in ingress-nginx logs alongside a 30,000ms response trace on search-api GET /search.\n2. I analyzed system metrics and found search-api CPU usage reaching a peak of 100% and averaging 91% with an increasing trend.\n3. I inspected recent commits and correlated the CPU bottleneck with commit d3c4b5a6, which reduced search-api HPA maxReplicas from 20 to 2, capping autoscaling capacity." } ], "answer": { "services": [ "search-api" ], "cause": [ [ "replica", "hpa", "autoscal", "scale", "scaling" ], [ "2", "max", "cap", "limit" ] ], "blame_sha": "d3c4b5a6", "wrong_shas": [ "a0b1c2d3" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "not blamed a0b1c2d": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h06_migration_lock", "set": "held_out", "category": "bad deploy", "name": "Migration rewrites a large table and locks it", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 22.2, "cost_usd": 0.000672, "tokens_input": 4578, "tokens_output": 1094, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "orders-api", "affected_services": [], "description": "Database queries in orders-api are timing out due to lock acquisition failure on relation 'orders_order'.", "root_cause": "Migration 0058_order_total_precision (commit 5f6e7d8c) modified the DecimalField precision on the orders_order table, requiring an ACCESS EXCLUSIVE table lock in PostgreSQL. Executing this migration while live traffic was querying orders_order led to statement lock timeouts.", "recommendation": "Avoid executing ALTER TABLE schema modifications directly on high-throughput tables in production during peak traffic. Apply migrations during low-traffic windows or use non-blocking zero-downtime migration patterns.", "linked_commits": [ { "sha": "5f6e7d8c", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed repeated OperationalError exceptions in orders-api logs reporting lock timeouts while locking tuples on relation 'orders_order' starting at 14:13:00.\n2. I checked recent commits and identified migration 0058_order_total_precision committed at 14:08:00, which alters the 'total' DecimalField on model 'Order'.\n3. Altering column data type/precision in PostgreSQL acquires an ACCESS EXCLUSIVE lock on the table, blocking concurrent application transactions and resulting in lock timeouts." } ], "answer": { "services": [ "orders-api", "postgres", "orders_order" ], "cause": [ [ "lock", "locked", "locking" ], [ "migration", "alter", "rewrite", "0058" ] ], "blame_sha": "5f6e7d8c", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h07_feature_flag", "set": "held_out", "category": "config", "name": "Feature-flag rollout with no deploy", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 32.4, "cost_usd": 0.000737, "tokens_input": 4469, "tokens_output": 1338, "issues": [ { "severity": "WARNING", "confidence": "HIGH", "component": "tax-svc", "affected_services": [], "description": "tax-svc throws TaxRuleNotFound errors for order tax calculations in region CA-QC when evaluated under tax engine v2.", "root_cause": "The feature flag enabling tax engine v2 is active for region CA-QC, but the v2 engine rule configuration for CA-QC is missing or incomplete.", "recommendation": "Add the CA-QC tax rule definition for engine v2 or disable the engine v2 feature flag for region CA-QC until rules are configured.", "linked_commits": [], "reasoning": "1. I observed repetitive TaxRuleNotFound errors in tax-svc logs specifically for region CA-QC under engine v2.\n2. I reviewed the recent code commit (8a9b0c1d) which only modified test fixtures for US-NY, ruling out a direct code release break in CA-QC calculation logic.\n3. I confirmed that orders routed through tax engine v2 consistently fail because the engine lacks a configured tax rule for Quebec (CA-QC)." } ], "answer": { "services": [ "tax-svc", "flags-svc" ], "cause": [ [ "flag", "rollout", "new-tax-engine", "engine=v2", "v2" ], [ "rule", "region", "ca-qc", "quebec" ] ], "blame_sha": null, "wrong_shas": [ "8a9b0c1d" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "not blamed 8a9b0c1": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h08_rate_limited", "set": "held_out", "category": "bad deploy", "name": "Carrier API rate limit after a polling schedule change", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 20.3, "cost_usd": 0.000725, "tokens_input": 4550, "tokens_output": 1280, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "shipping-rates", "affected_services": [], "description": "The shipping-rates service is encountering HTTP 429 Too Many Requests errors when calling api.carrier.example/v2/rates due to rate limit exhaustion.", "root_cause": "Commit c1d2e3f4 modified deploy/k8s/rates-refresh-cronjob.yaml schedule from '*/15 * * * *' to '* * * * *', increasing external carrier API calls from every 15 minutes to every 1 minute and triggering HTTP 429 rate limiting.", "recommendation": "Revert the CronJob schedule in deploy/k8s/rates-refresh-cronjob.yaml back to '*/15 * * * *' or respect the 3600-second Retry-After response header.", "linked_commits": [ { "sha": "c1d2e3f4", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed persistent HTTP 429 Too Many Requests error logs from shipping-rates starting at 2026-10-18T14:10:00+00:00.\n2. I examined recent code changes and identified commit c1d2e3f4 ('feat(shipping): fresher carrier rates') deployed shortly before the failure window.\n3. I confirmed in the commit diff that the CronJob schedule was changed from '*/15 * * * *' to '* * * * *', increasing rate-refresh frequency by 15x and overwhelming the external API quota." } ], "answer": { "services": [ "shipping-rates" ], "cause": [ [ "429", "rate limit", "rate-limit", "too many requests", "quota" ], [ "schedule", "cron", "every minute", "polling", "frequency", "15" ] ], "blame_sha": "c1d2e3f4", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h10_benign_spike", "set": "held_out", "category": "healthy", "name": "Traffic spike absorbed by autoscaling (nothing wrong)", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 10.7, "cost_usd": 0.000372, "tokens_input": 3736, "tokens_output": 305, "issues": [], "answer": { "services": [ "web" ], "cause": [], "blame_sha": null, "wrong_shas": [], "max_issues": 2, "benign_max": "WARNING", "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "silent": true }, "kind": "healthy", "alerting": 0, "commit_expected": false } }, { "id": "h11_red_herring", "set": "held_out", "category": "infrastructure", "name": "Rotated SMTP password, next to old unrelated 404 noise", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 14.9, "cost_usd": 0.000695, "tokens_input": 4094, "tokens_output": 1294, "issues": [ { "severity": "WARNING", "confidence": "HIGH", "component": "notifications-svc", "affected_services": [], "description": "notifications-svc is failing to send notifications due to SMTP authentication failures (535 Authentication credentials invalid).", "root_cause": "The SMTP username or password/API key configured for notifications-svc is invalid, expired, or was improperly updated.", "recommendation": "Verify and update the SMTP credential secret or environment variable for notifications-svc and ensure credentials are active on the SMTP provider side.", "linked_commits": [], "reasoning": "1. Observed repeated smtplib.SMTPAuthenticationError entries logged by notifications-svc returning code 535.\n2. Hypothesized that the underlying SMTP authentication credentials in the application's configuration or secret store are incorrect or expired.\n3. Confirmed that all 8 logs across a 7-minute period consistently fail with the same SMTP auth error without success." } ], "answer": { "services": [ "notifications-svc" ], "cause": [ [ "smtp", "email", "mail" ], [ "credential", "password", "auth", "535", "rotat" ] ], "blame_sha": null, "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [ "mobile-gateway" ] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "focused": true, "no critical on mobile-gateway": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h12_es_watermark", "set": "held_out", "category": "infrastructure", "name": "Elasticsearch disk watermark blocks writes for three services", "round": 1, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 35.7, "cost_usd": 0.000778, "tokens_input": 4271, "tokens_output": 1525, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "elasticsearch", "affected_services": [ "audit-svc", "logging-api", "search-api" ], "description": "Elasticsearch cluster disk usage exceeded the flood-stage watermark threshold, causing indices across multiple services (app-logs-2026.10.18, products-v7, audit-2026.10) to enter read-only-allow-delete mode.", "root_cause": "The Elasticsearch cluster node storage exceeded the flood-stage watermark (typically 95% disk usage), triggering automatic protection that blocks all index write operations.", "recommendation": "Free disk space on the Elasticsearch cluster nodes by removing old unneeded indices or expanding volume capacity, then clear the index read-only block settings.", "linked_commits": [], "reasoning": "1. I observed recurring ClusterBlockException errors in logging-api, search-api, and audit-svc starting at 14:06:00 UTC.\n2. I analyzed the exception message which explicitly identified 'disk usage exceeded flood-stage watermark' and 'read-only-allow-delete block' as the block cause.\n3. I reviewed recent code change f1e2d3c4 and verified it was a minor frontend CSS modification unrelated to backend or storage functionality.\n4. I confirmed that storage depletion on the underlying Elasticsearch cluster is the single root cause impacting all dependent services." } ], "answer": { "services": [ "elasticsearch", "es-data-2" ], "cause": [ [ "disk", "watermark", "flood" ], [ "read-only", "read only", "readonly", "block" ] ], "blame_sha": null, "wrong_shas": [ "f1e2d3c4" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "not blamed f1e2d3c": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h01_connection_leak", "set": "held_out", "category": "bad deploy", "name": "Connection leak on an error path (pool size unchanged)", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 25.4, "cost_usd": 0.000732, "tokens_input": 5315, "tokens_output": 1110, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "inventory-api", "affected_services": [], "description": "SQLAlchemy connection pool exhausted (QueuePool limit 40 reached) due to unclosed database sessions in reserve function.", "root_cause": "Commit 4b0e77d1 refactored database session handling in inventory/stock.py from a context manager ('with self.db.session() as s:') to manual assignment ('s = self.db.session()'). When an OutOfStock exception is raised (or any unhandled error occurs), 's.close()' is bypassed, leaking DB connections until the 40-connection QueuePool is exhausted.", "recommendation": "Refactor reserve() in inventory/stock.py to use a context manager ('with self.db.session() as s:') or ensure 's.close()' is invoked within a try...finally block.", "linked_commits": [ { "sha": "4b0e77d1", "provider": "unknown", "project_id": null } ], "reasoning": "1. Observed repeating sqlalchemy.exc.TimeoutError errors in inventory-api indicating the QueuePool limit of 40 connections was exceeded.\n2. Correlated the stack trace in inventory/stock.py with commit 4b0e77d1, which replaced the session context manager with manual s.close().\n3. Confirmed that raising OutOfStock before s.close() leaves session connections open indefinitely, leaking connections until the pool is full." } ], "answer": { "services": [ "inventory-api" ], "cause": [ [ "leak", "not closed", "never closed", "stays open", "left open", "not released", "never released", "not returned", "close" ] ], "blame_sha": "4b0e77d1", "wrong_shas": [ "9c1d2e3f" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "not blamed 9c1d2e3": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h02_retry_storm", "set": "held_out", "category": "bad deploy", "name": "Retry storm from a client change overloads a healthy service", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 26.5, "cost_usd": 0.000756, "tokens_input": 4317, "tokens_output": 1440, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "product-page", "affected_services": [ "ratings-svc" ], "description": "Commit e5a91b02 modified the ratings client retry strategy in product-page to retry 10 times with 0ms fixed delay (removing exponential backoff and jitter). This produced an immediate retry storm when ratings requests failed, flooding ratings-svc, exhausting its request queue (1024 waiting), spiking CPU usage to 99%, and returning HTTP 503 errors.", "root_cause": "Commit e5a91b02 in web/src/clients/ratings.ts changed retry attempts from 3 to 10 and changed backoff from exponential with jitter to a 0ms fixed delay, triggering an aggressive retry storm that overwhelmed ratings-svc.", "recommendation": "Revert commit e5a91b02 or update web/src/clients/ratings.ts to use exponential backoff with jitter and a lower retry limit (e.g., 3 attempts).", "linked_commits": [ { "sha": "e5a91b02", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed high CPU usage (99%) and 503 request queue full errors on ratings-svc alongside repeated retry warnings from product-page.\n2. I examined commit e5a91b02 deployed at 14:26:00Z and saw that retry backoff was set to 0ms delay with 10 attempts.\n3. I confirmed that removing delay and jitter caused product-page to flood ratings-svc with instantaneous retries, exhausting the queue and spiking CPU." } ], "answer": { "services": [ "product-page" ], "cause": [ [ "retry", "retries", "retrying" ], [ "backoff", "back-off", "storm", "amplif", "10 attempts", "attempts", "delay" ] ], "blame_sha": "e5a91b02", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h03_kafka_rebalance", "set": "held_out", "category": "config", "name": "Kafka consumer rebalance loop after a poll-size change", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 30.0, "cost_usd": 0.000783, "tokens_input": 4398, "tokens_output": 1509, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "order-events-consumer", "affected_services": [], "description": "Kafka consumer order-events-consumer is repeatedly failing to commit offsets with CommitFailedException because batch processing times exceed max.poll.interval.ms, triggering consumer group rebalances.", "root_cause": "Commit 71f0c3aa increased `max-poll-records` tenfold from 500 to 5000 in application.yaml without increasing `max.poll.interval.ms` (300000ms). The consumer cannot process 5000 records within 5 minutes, leading to poll timeouts, consumer group rebalances, and repeated offset commit failures.", "recommendation": "Reduce `max-poll-records` back to 500 or increase `max.poll.interval.ms` in `consumer/src/main/resources/application.yaml` to ensure batch processing completes within the allowed polling interval.", "linked_commits": [ { "sha": "71f0c3aa", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed recurring consumer poll timeouts and CommitFailedException errors in the order-events-consumer logs between 14:22:00 and 14:42:00 UTC.\n2. I checked recent commits and identified commit 71f0c3aa deployed at 14:15:00 UTC, which increased max-poll-records from 500 to 5000.\n3. I confirmed that processing 5000 records per poll exceeds the configured 300,000ms max.poll.interval.ms limit, causing Kafka to mark the consumer dead and reassign partitions before offset commits complete." } ], "answer": { "services": [ "order-events-consumer" ], "cause": [ [ "poll", "max-poll-records", "max.poll" ], [ "5000", "records", "rebalanc", "interval", "processing time" ] ], "blame_sha": "71f0c3aa", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h04_clock_skew", "set": "held_out", "category": "infrastructure", "name": "Clock skew on one node rejects valid tokens", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 30.4, "cost_usd": 0.000613, "tokens_input": 4154, "tokens_output": 1004, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "auth-gateway", "affected_services": [], "description": "auth-gateway is repeatedly rejecting JWT tokens because the token issued-at timestamp (iat) is in the future relative to the auth-gateway system time.", "root_cause": "Clock skew between the auth-gateway node and the token issuing authority, or a lack of configured clock drift leeway in the JWT validation library, causes freshly issued tokens to be marked invalid because iat > now.", "recommendation": "Verify and synchronize system clocks across nodes using NTP (e.g. chrony/systemd-timesyncd) and add a small leeway parameter (e.g., 30-60 seconds) to JWT validation settings.", "linked_commits": [], "reasoning": "1. Observed multiple recurring ERROR log entries in auth-gateway stating 'JWT rejected: token used before issued (iat=[PHONE], now=[PHONE])'.\n2. Reviewed recent code commit 2aa7d19c which only introduced structured logging imports and did not alter token verification logic.\n3. Confirmed that the root cause is system clock drift between services or missing clock drift leeway during JWT parsing." } ], "answer": { "services": [ "node-c", "chronyd", "auth-gateway" ], "cause": [ [ "clock", "time sync", "ntp", "chrony", "skew", "drift" ] ], "blame_sha": null, "wrong_shas": [ "2aa7d19c" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "not blamed 2aa7d19": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h05_hpa_cap", "set": "held_out", "category": "config", "name": "Autoscaler capped at 2 replicas during a traffic spike", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 28.0, "cost_usd": 0.000791, "tokens_input": 4524, "tokens_output": 1505, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "search-api", "affected_services": [ "ingress-nginx" ], "description": "Upstream connection timeouts (110: Connection timed out) occurring at ingress-nginx when forwarding requests to search-api due to severe CPU saturation (99%-100%) caused by restrictive HPA maxReplicas settings.", "root_cause": "Commit d3c4b5a6 changed maxReplicas from 20 to 2 in deploy/k8s/search-api-hpa.yaml. This capped horizontal pod autoscaling, leaving search-api underprovisioned during load spikes and causing CPU utilization to reach 100%, triggering 30s request timeouts at the ingress controller.", "recommendation": "Revert commit d3c4b5a6 or update deploy/k8s/search-api-hpa.yaml to increase search-api maxReplicas back to 20.", "linked_commits": [ { "sha": "d3c4b5a6", "provider": "unknown", "project_id": null } ], "reasoning": "1. Observed repeated 110 Connection timed out errors in ingress-nginx logs and a 30000ms span latency in traces for GET /search on search-api.\n2. Checked service CPU metrics and found search-api CPU at 99% current and 100% peak with an increasing trend.\n3. Correlated the resource saturation with recent commit d3c4b5a6, which reduced maxReplicas in deploy/k8s/search-api-hpa.yaml from 20 to 2, preventing HPA from scaling pods under high traffic." } ], "answer": { "services": [ "search-api" ], "cause": [ [ "replica", "hpa", "autoscal", "scale", "scaling" ], [ "2", "max", "cap", "limit" ] ], "blame_sha": "d3c4b5a6", "wrong_shas": [ "a0b1c2d3" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "not blamed a0b1c2d": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h06_migration_lock", "set": "held_out", "category": "bad deploy", "name": "Migration rewrites a large table and locks it", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 58.2, "cost_usd": 0.000728, "tokens_input": 4577, "tokens_output": 1284, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "orders-api", "affected_services": [], "description": "orders-api encountered repeated database statement lock timeouts while attempting to lock rows in relation orders_order following a column precision migration.", "root_cause": "Commit 5f6e7d8c introduced migration 0058_order_total_precision altering the DecimalField schema for the total column on the orders_order table. Applying this schema alteration acquired exclusive locks on orders_order, causing concurrent transaction row locks in orders-api to exceed the database lock timeout.", "recommendation": "Perform column type alterations using multi-step zero-downtime migration patterns (e.g. adding a new column and migrating data asynchronously) or execute schema migrations during low-traffic maintenance windows.", "linked_commits": [ { "sha": "5f6e7d8c", "provider": "unknown", "project_id": null } ], "reasoning": "1. Observed 10 OperationalError log entries reporting lock timeouts on relation orders_order in orders-api between 14:13:00 and 14:17:00.\n2. Checked recent commits and found migration 0058_order_total_precision committed at 14:08:00 altering the total DecimalField on orders_order.\n3. Correlated the timing of the migration with the log errors, confirming that the DDL operation held database table locks blocking API queries." } ], "answer": { "services": [ "orders-api", "postgres", "orders_order" ], "cause": [ [ "lock", "locked", "locking" ], [ "migration", "alter", "rewrite", "0058" ] ], "blame_sha": "5f6e7d8c", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h07_feature_flag", "set": "held_out", "category": "config", "name": "Feature-flag rollout with no deploy", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 17.8, "cost_usd": 0.000681, "tokens_input": 4470, "tokens_output": 1153, "issues": [ { "severity": "WARNING", "confidence": "HIGH", "component": "tax-svc", "affected_services": [], "description": "Tax calculation fails with TaxRuleNotFound for region CA-QC under tax engine v2.", "root_cause": "The tax service (`tax-svc`) lacks a defined tax rule for region `CA-QC` under tax calculation engine `v2`, leading to recurring `TaxRuleNotFound` errors during order processing.", "recommendation": "Add missing tax rules for region `CA-QC` to the `v2` engine configuration in `tax-svc` or add a fallback mechanism for unsupported region/engine combinations.", "linked_commits": [], "reasoning": "1. I observed repeated `TaxRuleNotFound` error logs in `tax-svc` while processing orders for region CA-QC using engine v2.\n2. I checked the commit history to see if recent changes altered tax rules, but commit 8a9b0c1d only added test fixtures for US-NY.\n3. I confirmed the failure is due to a missing CA-QC rule configuration in tax engine v2." } ], "answer": { "services": [ "tax-svc", "flags-svc" ], "cause": [ [ "flag", "rollout", "new-tax-engine", "engine=v2", "v2" ], [ "rule", "region", "ca-qc", "quebec" ] ], "blame_sha": null, "wrong_shas": [ "8a9b0c1d" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "not blamed 8a9b0c1": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h08_rate_limited", "set": "held_out", "category": "bad deploy", "name": "Carrier API rate limit after a polling schedule change", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 17.5, "cost_usd": 0.000701, "tokens_input": 4550, "tokens_output": 1200, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "shipping-rates", "affected_services": [], "description": "The shipping-rates service is receiving 429 Too Many Requests from the third-party carrier API due to rate limits being exhausted.", "root_cause": "Commit c1d2e3f4 changed the Kubernetes CronJob schedule in deploy/k8s/rates-refresh-cronjob.yaml from '*/15 * * * *' to '* * * * *', increasing requests to api.carrier.example 15-fold and triggering HTTP 429 rate limiting.", "recommendation": "Revert commit c1d2e3f4 to restore the rates refresh CronJob schedule to every 15 minutes ('*/15 * * * *') or adjust the polling frequency to stay within third-party rate limits.", "linked_commits": [ { "sha": "c1d2e3f4", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed persistent HTTP 429 Too Many Requests errors when calling https://api.carrier.example/v2/rates every minute starting at 14:10:00.\n2. I inspected recent code changes and identified commit c1d2e3f4 in deploy/k8s/rates-refresh-cronjob.yaml, which updated the CronJob execution schedule from every 15 minutes to every minute.\n3. I confirmed that the 15x increase in request frequency exhausted the carrier API rate limits, causing requests to fail with X-RateLimit-Remaining: 0 and Retry-After: 3600." } ], "answer": { "services": [ "shipping-rates" ], "cause": [ [ "429", "rate limit", "rate-limit", "too many requests", "quota" ], [ "schedule", "cron", "every minute", "polling", "frequency", "15" ] ], "blame_sha": "c1d2e3f4", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h10_benign_spike", "set": "held_out", "category": "healthy", "name": "Traffic spike absorbed by autoscaling (nothing wrong)", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 10.5, "cost_usd": 0.000398, "tokens_input": 3735, "tokens_output": 394, "issues": [], "answer": { "services": [ "web" ], "cause": [], "blame_sha": null, "wrong_shas": [], "max_issues": 2, "benign_max": "WARNING", "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "silent": true }, "kind": "healthy", "alerting": 0, "commit_expected": false } }, { "id": "h11_red_herring", "set": "held_out", "category": "infrastructure", "name": "Rotated SMTP password, next to old unrelated 404 noise", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 26.8, "cost_usd": 0.000584, "tokens_input": 4096, "tokens_output": 921, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "notifications-svc", "affected_services": [], "description": "notifications-svc is experiencing consistent authentication failures when connecting to the SMTP server.", "root_cause": "The SMTP username or password used by notifications-svc is invalid, expired, or misconfigured, causing the remote SMTP server to return error 535.", "recommendation": "Update and verify the SMTP credential secret configured for notifications-svc.", "linked_commits": [], "reasoning": "1. Observed continuous smtplib.SMTPAuthenticationError entries in notifications-svc logs every minute from 14:32:00 to 14:39:00.\n2. Analyzed error response code (535, 5.7.8), which explicitly indicates invalid authentication credentials on the mail server.\n3. Confirmed that notification attempts are persistently failing due to authentication failure." } ], "answer": { "services": [ "notifications-svc" ], "cause": [ [ "smtp", "email", "mail" ], [ "credential", "password", "auth", "535", "rotat" ] ], "blame_sha": null, "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [ "mobile-gateway" ] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "focused": true, "no critical on mobile-gateway": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h12_es_watermark", "set": "held_out", "category": "infrastructure", "name": "Elasticsearch disk watermark blocks writes for three services", "round": 2, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 33.3, "cost_usd": 0.000777, "tokens_input": 4272, "tokens_output": 1521, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "elasticsearch", "affected_services": [ "audit-svc", "logging-api", "search-api" ], "description": "Elasticsearch cluster disk usage exceeded the flood-stage watermark, causing indices to enter read-only mode and failing all write operations across logging-api, search-api, and audit-svc.", "root_cause": "The Elasticsearch cluster disk usage crossed its flood-stage watermark threshold, automatically applying a 'read-only-allow-delete' index block on indices including app-logs-2026.10.18, products-v7, and audit-2026.10.", "recommendation": "Free up disk space on the Elasticsearch cluster by deleting old indices or expanding volume capacity, then clear the index read-only block by setting index.blocks.read_only_allow_delete to null.", "linked_commits": [], "reasoning": "1. I observed repeated ClusterBlockException errors in logging-api, search-api, and audit-svc indicating disk usage exceeded flood-stage watermark.\n2. I reviewed recent code commits and found only a minor UI CSS update (web/styles/buttons.css), confirming the issue is infrastructure-related.\n3. I confirmed that Elasticsearch automatically placed indices in read-only-allow-delete mode due to insufficient free disk space." } ], "answer": { "services": [ "elasticsearch", "es-data-2" ], "cause": [ [ "disk", "watermark", "flood" ], [ "read-only", "read only", "readonly", "block" ] ], "blame_sha": null, "wrong_shas": [ "f1e2d3c4" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "not blamed f1e2d3c": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h01_connection_leak", "set": "held_out", "category": "bad deploy", "name": "Connection leak on an error path (pool size unchanged)", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 25.3, "cost_usd": 0.000777, "tokens_input": 5315, "tokens_output": 1261, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "inventory-api", "affected_services": [], "description": "Database connection pool exhaustion (sqlalchemy.exc.TimeoutError: QueuePool limit of size 40 overflow 0 reached) causing timeouts on inventory reserve endpoint.", "root_cause": "Commit 4b0e77d1 replaced the context manager `with self.db.session() as s:` in `inventory/stock.py` with explicit session handling. When `OutOfStock` exception is raised or any error occurs before `s.close()`, the session remains open. This leaks database connections until the QueuePool limit (40) is exhausted.", "recommendation": "Restore context manager usage (`with self.db.session() as s:`) or wrap session handling in a try/finally block in `inventory/stock.py` to ensure `s.close()` is executed on every code path.", "linked_commits": [ { "sha": "4b0e77d1", "provider": "unknown", "project_id": null } ], "reasoning": "1. Observed repeated `sqlalchemy.exc.TimeoutError` errors in `inventory-api` logs indicating QueuePool limit of size 40 was reached.\n2. Checked recent commits and found commit 4b0e77d1 in `inventory/stock.py` which removed the `with self.db.session() as s:` context manager.\n3. Confirmed that when `OutOfStock(sku)` is raised in `reserve()`, `s.close()` is bypassed, leaking database connections until pool exhaustion." } ], "answer": { "services": [ "inventory-api" ], "cause": [ [ "leak", "not closed", "never closed", "stays open", "left open", "not released", "never released", "not returned", "close" ] ], "blame_sha": "4b0e77d1", "wrong_shas": [ "9c1d2e3f" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "not blamed 9c1d2e3": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h02_retry_storm", "set": "held_out", "category": "bad deploy", "name": "Retry storm from a client change overloads a healthy service", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 37.5, "cost_usd": 0.000817, "tokens_input": 4317, "tokens_output": 1645, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "product-page", "affected_services": [ "ratings-svc" ], "description": "Commit e5a91b02 updated the ratings HTTP client retry strategy in product-page to 10 attempts with 0ms delay and no backoff/jitter. This triggered a severe retry storm against ratings-svc, exhausting its request queue (1024 waiting), spiking its CPU to 99%, and leading to 2,600 trace errors and repeated 503 Service Unavailable responses.", "root_cause": "Commit e5a91b02 in product-page changed the ratings client retry configuration from exponential backoff (200ms\u20135000ms with jitter) to 10 retry attempts with a fixed 0ms delay. When ratings requests experienced initial failures, product-page immediately bombarded ratings-svc with immediate unthrottled retries, overwhelming ratings-svc request queue and causing CPU usage to hit 99%.", "recommendation": "Revert commit e5a91b02 or update web/src/clients/ratings.ts to restore exponential backoff with non-zero delay and jitter, and reduce the retry count to a lower threshold (e.g., 3).", "linked_commits": [ { "sha": "e5a91b02", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed widespread 503 errors on ratings-svc alongside persistent retry warnings from product-page and a CPU spike to 99% on ratings-svc.\n2. I checked recent code commits and identified commit e5a91b02 in product-page which set retry attempts to 10 with delayMs: 0 and backoff type fixed.\n3. I confirmed that zero-delay retries caused an immediate retry storm, flooding ratings-svc's request queue (1024 depth) and driving CPU saturation." } ], "answer": { "services": [ "product-page" ], "cause": [ [ "retry", "retries", "retrying" ], [ "backoff", "back-off", "storm", "amplif", "10 attempts", "attempts", "delay" ] ], "blame_sha": "e5a91b02", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h03_kafka_rebalance", "set": "held_out", "category": "config", "name": "Kafka consumer rebalance loop after a poll-size change", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 42.8, "cost_usd": 0.000798, "tokens_input": 4399, "tokens_output": 1561, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "order-events-consumer", "affected_services": [], "description": "Kafka consumer order-events-consumer is repeatedly timing out during poll cycles and failing offset commits with CommitFailedException due to constant consumer group rebalancing.", "root_cause": "Commit 71f0c3aa increased max-poll-records from 500 to 5000 in application.yaml without increasing max.poll.interval.ms (300000ms). Processing a 10x larger batch of 5000 records exceeds the 5-minute poll interval, causing Kafka to mark the consumer dead, rebalance partitions, and reject offset commits.", "recommendation": "Revert max-poll-records back to 500 in consumer/src/main/resources/application.yaml, or increase max.poll.interval.ms to allow sufficient time for processing 5000 records.", "linked_commits": [ { "sha": "71f0c3aa", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed recurring WARN logs regarding expired poll timeouts followed by ERROR logs with CommitFailedException in order-events-consumer starting at 14:22:00.\n2. I correlated the onset of these errors with commit 71f0c3aa at 14:15:00, which increased max-poll-records from 500 to 5000 while leaving max.poll.interval.ms at 300,000ms.\n3. I confirmed that processing 5000 records per batch exceeds the 5-minute timeout window, causing Kafka to evict the consumer instance from the group and trigger continuous rebalances." } ], "answer": { "services": [ "order-events-consumer" ], "cause": [ [ "poll", "max-poll-records", "max.poll" ], [ "5000", "records", "rebalanc", "interval", "processing time" ] ], "blame_sha": "71f0c3aa", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h04_clock_skew", "set": "held_out", "category": "infrastructure", "name": "Clock skew on one node rejects valid tokens", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 17.1, "cost_usd": 0.000592, "tokens_input": 4154, "tokens_output": 934, "issues": [ { "severity": "WARNING", "confidence": "HIGH", "component": "auth-gateway", "affected_services": [], "description": "JWT tokens are being rejected by auth-gateway because the token issued-at timestamp (iat) is in the future relative to the gateway's local system time.", "root_cause": "Clock skew between the identity provider/token issuer node and the auth-gateway node causes newly minted JWTs to have an 'iat' timestamp greater than the local system time ('now') on auth-gateway.", "recommendation": "Resynchronize system clocks across nodes using NTP (e.g. chrony/ntp) and configure a leeway/tolerance (e.g., 5 seconds) in the JWT parser logic on auth-gateway to handle minor clock drift.", "linked_commits": [], "reasoning": "1. I observed repeated error logs in auth-gateway stating 'JWT rejected: token used before issued (iat=[PHONE], now=[PHONE])'.\n2. I examined the recent code change (commit 2aa7d19c) and verified it only added a structured logging import without changing token validation rules.\n3. I concluded that clock drift between the token issuing service and auth-gateway is causing legitimate tokens to fail validation due to strict timestamp evaluation." } ], "answer": { "services": [ "node-c", "chronyd", "auth-gateway" ], "cause": [ [ "clock", "time sync", "ntp", "chrony", "skew", "drift" ] ], "blame_sha": null, "wrong_shas": [ "2aa7d19c" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "not blamed 2aa7d19": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h05_hpa_cap", "set": "held_out", "category": "config", "name": "Autoscaler capped at 2 replicas during a traffic spike", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 28.6, "cost_usd": 0.000769, "tokens_input": 4525, "tokens_output": 1431, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "search-api", "affected_services": [ "ingress-nginx" ], "description": "ingress-nginx is timing out while reading response headers from search-api due to severe search-api CPU saturation caused by HPA replica capping.", "root_cause": "Commit d3c4b5a6 reduced maxReplicas in deploy/k8s/search-api-hpa.yaml from 20 to 2. This prevented the search-api deployment from scaling horizontally during incoming traffic, causing CPU utilization to hit 100% and request response times to reach 30,000ms, triggering upstream timeouts in ingress-nginx.", "recommendation": "Revert commit d3c4b5a6 or update maxReplicas in deploy/k8s/search-api-hpa.yaml back to 20 to allow search-api to scale out under load.", "linked_commits": [ { "sha": "d3c4b5a6", "provider": "unknown", "project_id": null } ], "reasoning": "1. Observed multiple upstream connection timeout logs from ingress-nginx targeting search-api alongside 410 trace errors with span latencies hitting 30,000ms.\n2. Checked system metrics and identified that search-api CPU utilization was saturated at 99% current and 100% peak.\n3. Correlated the CPU saturation with commit d3c4b5a6, which reduced maxReplicas from 20 to 2 in search-api-hpa.yaml, effectively disabling autoscaling capability." } ], "answer": { "services": [ "search-api" ], "cause": [ [ "replica", "hpa", "autoscal", "scale", "scaling" ], [ "2", "max", "cap", "limit" ] ], "blame_sha": "d3c4b5a6", "wrong_shas": [ "a0b1c2d3" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "not blamed a0b1c2d": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h06_migration_lock", "set": "held_out", "category": "bad deploy", "name": "Migration rewrites a large table and locks it", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 22.7, "cost_usd": 0.000658, "tokens_input": 4579, "tokens_output": 1049, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "orders-api", "affected_services": [], "description": "The orders-api service is experiencing repeated database lock timeouts on relation orders_order following a recent schema migration.", "root_cause": "Migration 0058_order_total_precision in commit 5f6e7d8c altered the DecimalField precision for the Order total column, which acquired an AccessExclusiveLock on the orders_order table and blocked concurrent database operations, causing statement lock timeouts.", "recommendation": "Avoid running restrictive field alteration migrations on heavily written tables during live operations, or run migration scripts asynchronously using zero-downtime migration patterns.", "linked_commits": [ { "sha": "5f6e7d8c", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed multiple OperationalError log entries in orders-api showing statement cancellation due to lock timeouts on orders_order starting at 14:13:00.\n2. I checked code commits and identified migration commit 5f6e7d8c deployed at 14:08:00, which alters the 'total' field precision on the Order model.\n3. I correlated the timeline and nature of PostgreSQL table locks during schema alterations to confirm the migration locked orders_order tuples and blocked concurrent application queries." } ], "answer": { "services": [ "orders-api", "postgres", "orders_order" ], "cause": [ [ "lock", "locked", "locking" ], [ "migration", "alter", "rewrite", "0058" ] ], "blame_sha": "5f6e7d8c", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h07_feature_flag", "set": "held_out", "category": "config", "name": "Feature-flag rollout with no deploy", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 39.3, "cost_usd": 0.000668, "tokens_input": 4470, "tokens_output": 1110, "issues": [ { "severity": "WARNING", "confidence": "HIGH", "component": "tax-svc", "affected_services": [], "description": "Tax calculation failed for region CA-QC under tax engine v2 due to missing tax rule configuration.", "root_cause": "The v2 tax calculation engine lacks tax rule definitions for the region 'CA-QC', causing TaxRuleNotFound errors whenever orders targeting Quebec are processed under v2.", "recommendation": "Add the missing tax rule for region CA-QC in the v2 tax engine rules database/configuration, or fall back to tax engine v1 for unsupported regions.", "linked_commits": [], "reasoning": "1. I observed repeated ERROR logs from tax-svc showing 'TaxRuleNotFound: no rule for region=CA-QC (engine=v2)' for orders 7700 through 7711.\n2. I reviewed recent commit 8a9b0c1d, which only modified test fixtures for US-NY, confirming it did not introduce or fix CA-QC tax rules.\n3. I confirmed the failures are localized to engine=v2 operations for region CA-QC, indicating incomplete feature rollout or missing region mapping in the v2 engine configuration." } ], "answer": { "services": [ "tax-svc", "flags-svc" ], "cause": [ [ "flag", "rollout", "new-tax-engine", "engine=v2", "v2" ], [ "rule", "region", "ca-qc", "quebec" ] ], "blame_sha": null, "wrong_shas": [ "8a9b0c1d" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "not blamed 8a9b0c1": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h08_rate_limited", "set": "held_out", "category": "bad deploy", "name": "Carrier API rate limit after a polling schedule change", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 29.2, "cost_usd": 0.00071, "tokens_input": 4549, "tokens_output": 1229, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "shipping-rates", "affected_services": [], "description": "The shipping-rates service is receiving HTTP 429 Too Many Requests responses from the third-party carrier API due to exceeding rate limits.", "root_cause": "Commit c1d2e3f4 changed the Kubernetes CronJob schedule in deploy/k8s/rates-refresh-cronjob.yaml from every 15 minutes ('*/15 * * * *') to every 1 minute ('* * * * *'). This 15x increase in request frequency exhausted the carrier API quota after one hour, causing HTTP 429 errors.", "recommendation": "Revert commit c1d2e3f4 or reduce the CronJob schedule back to '*/15 * * * *' to align with the external provider's API rate limits.", "linked_commits": [ { "sha": "c1d2e3f4", "provider": "unknown", "project_id": null } ], "reasoning": "1. I observed repeated HTTP 429 Too Many Requests errors logged by shipping-rates starting at 14:10:00 UTC when attempting to fetch carrier rates.\n2. I inspected recent code changes and found commit c1d2e3f4 ('feat(shipping): fresher carrier rates') deployed an hour prior, which increased CronJob frequency from 15-minute intervals to every 1 minute.\n3. I correlated the 15x increase in execution rate with the exhaustion of API rate limit quota (X-RateLimit-Remaining: 0, Retry-After: 3600), confirming the configuration change directly caused the API rate limiting." } ], "answer": { "services": [ "shipping-rates" ], "cause": [ [ "429", "rate limit", "rate-limit", "too many requests", "quota" ], [ "schedule", "cron", "every minute", "polling", "frequency", "15" ] ], "blame_sha": "c1d2e3f4", "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "top commit": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": true } }, { "id": "h10_benign_spike", "set": "held_out", "category": "healthy", "name": "Traffic spike absorbed by autoscaling (nothing wrong)", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 11.1, "cost_usd": 0.000394, "tokens_input": 3735, "tokens_output": 379, "issues": [], "answer": { "services": [ "web" ], "cause": [], "blame_sha": null, "wrong_shas": [], "max_issues": 2, "benign_max": "WARNING", "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "silent": true }, "kind": "healthy", "alerting": 0, "commit_expected": false } }, { "id": "h11_red_herring", "set": "held_out", "category": "infrastructure", "name": "Rotated SMTP password, next to old unrelated 404 noise", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 25.2, "cost_usd": 0.000597, "tokens_input": 4096, "tokens_output": 967, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "notifications-svc", "affected_services": [], "description": "The notifications-svc component is repeatedly failing to authenticate with the upstream SMTP mail server, preventing email notifications from being sent.", "root_cause": "The notifications-svc is attempting to authenticate with an SMTP mail server using invalid, expired, or improperly configured credentials (SMTP status code 535: 5.7.8 Authentication credentials invalid).", "recommendation": "Verify and update the SMTP authentication credentials (username, password, or API key) configured in secret manager or environment variables for notifications-svc.", "linked_commits": [], "reasoning": "1. Observed repeated smtplib.SMTPAuthenticationError log lines originating from notifications-svc between 14:32:00 and 14:39:00.\n2. The error message explicitly returns SMTP code 535 with payload '5.7.8 Authentication credentials invalid', confirming a credential authorization failure with the upstream SMTP service.\n3. Ruled out general network connection issues as the connection to the SMTP server succeeds prior to failing authentication." } ], "answer": { "services": [ "notifications-svc" ], "cause": [ [ "smtp", "email", "mail" ], [ "credential", "password", "auth", "535", "rotat" ] ], "blame_sha": null, "wrong_shas": [], "max_issues": 2, "benign_max": null, "decoy_services": [ "mobile-gateway" ] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "focused": true, "no critical on mobile-gateway": true }, "kind": "incident", "alerting": 1, "commit_expected": false } }, { "id": "h12_es_watermark", "set": "held_out", "category": "infrastructure", "name": "Elasticsearch disk watermark blocks writes for three services", "round": 3, "provider": "gemini", "model": "gemini-3.6-flash", "ai_called": true, "error": null, "seconds": 33.3, "cost_usd": 0.000698, "tokens_input": 4271, "tokens_output": 1259, "issues": [ { "severity": "CRITICAL", "confidence": "HIGH", "component": "elasticsearch", "affected_services": [ "audit-svc", "logging-api", "search-api" ], "description": "Elasticsearch indices entered read-only-allow-delete mode because node disk usage exceeded the flood-stage watermark, causing write operations to fail across multiple services.", "root_cause": "Elasticsearch cluster nodes exceeded the flood-stage disk watermark threshold (default 95%), placing indices (app-logs-2026.10.18, products-v7, audit-2026.10) into read-only-allow-delete state and blocking incoming write requests from logging-api, search-api, and audit-svc.", "recommendation": "Free disk space on the Elasticsearch cluster by purging old indices or scaling persistent volumes. Once disk usage drops below the flood-stage watermark, remove the read-only block using index setting updates (`PUT /*/_settings {\"index.blocks.read_only_allow_delete\": null}`).", "linked_commits": [], "reasoning": "1. I observed recurring ClusterBlockException errors across logging-api, search-api, and audit-svc starting at 14:06:00.\n2. The log entries explicitly cite disk usage exceeding the flood-stage watermark and placing multiple indices into read-only-allow-delete mode.\n3. I reviewed recent code commits and found only a frontend CSS commit (f1e2d3c4), confirming the root cause is infrastructure storage exhaustion rather than a application code regression.\n4. I confirmed the cluster-wide impact on write capabilities for logging, product indexing, and audit logging services." } ], "answer": { "services": [ "elasticsearch", "es-data-2" ], "cause": [ [ "disk", "watermark", "flood" ], [ "read-only", "read only", "readonly", "block" ] ], "blame_sha": null, "wrong_shas": [ "f1e2d3c4" ], "max_issues": 2, "benign_max": null, "decoy_services": [] }, "score": { "verdict": true, "root_cause": true, "lenient": true, "checks": { "detected": true, "top service": true, "top cause": true, "not blamed f1e2d3c": true, "focused": true }, "kind": "incident", "alerting": 1, "commit_expected": false } } ] }