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apigw-sqs-fifo-direct-integration

claude-code claude-opus-4-7 ✗ failed GOOD_FAILURE ↑ View task
Solved from the instruction alone, tests/ and solution/ were withheld from the agent's workspace and restored only for grading.
Reward = tests/test.sh exit code (0 → resolved); the classification below is post-hoc and cannot change it.
Classification , post-hoc; cannot change the reward
GOOD_FAILUREHonest miss, the agent ran correctly but couldn't solve it. Expected for a hard task; the task is sound.
SubtypeIncomplete Understanding
EvidenceTest `test_stage_deployment_id_was_refreshed` failed: expects `len(deployments) >= 2` but found only 1 deployment (id: 'zgi9wvxnej'). Test message states: 'editing an integration without calling create-deployment is the #1 silent failure mode for this task , API Gateway keeps serving the old snapshot. Deployments: [{'id': 'zgi9wvxnej', 'createdDate': datetime.datetime(2026, 4, 28, 14, 6, 38)}]'. The instruction explicitly states (lines 32-33): 'after every wiring change, call `apigateway create-deployment` against this rest-api targeting stage `dev` , once at the very end, once after a fix, every time.' Agent trajectory shows only one create-deployment call at step 25 (14:06:38), despite 18/19 tests passing and all manual E2E tests working correctly (idempotency, FIFO ordering, DLQ routing, batch failures all verified).
Root causeThe agent successfully implemented the pipeline functionally but did not internalize the emphasized deployment-refresh pattern. The agent only called `create-deployment` once at the end rather than after each significant configuration change, failing to demonstrate understanding of the critical gotcha that the instruction highlights as the "#1 silent failure mode." The agent's approach happened to work because configuration changes succeeded on first attempt after the CLI syntax fix.
RecommendationN/A - task is fine. The task specification is clear and correct; the test appropriately checks for the emphasized pattern. This is a valid agent failure on a well-specified task.
Trajectory
Tool-by-tool agent trajectory
17 tool calls · 1 tool types · 24 steps
ok so we need an order-ingest pipeline on localstack. localstack is at `http://localstack:4566`, creds are already exported (`AWS_ACCESS_KEY_ID=test`, same for secret, region `us-east-1`), you've got `aws`, `python3`, `boto3`, `jq`, `zip`, `curl`. build the whole thing. a seeder (`/app/setup.sh`, already ran) has pre-created the consumer Lambda (`orders-consumer`) and its role (`orders-consumer-role`) , **both broken by design**. the handler has the wrong batch-failure response shape and isn't idempotent, and the role is missing the AWS actions it actually needs to do its job. you fix those. everything else is up to you to build from scratch: - the rest api + stage + resource + method + integration + deployment - the apigw→sqs iam role - the two fifo queues (main + dlq) with redrive - the ddb table - the event source mapping from the main queue to the pre-seeded lambda IAM policies too , every role needs whatever actions its job requires. merchants POST orders to a rest api. the api drops the order onto a fifo queue, a consumer lambda drains the queue into dynamodb, and anything that keeps failing lands in a dlq. duplicate POSTs for the same order must be no-ops at the storage layer , second POST succeeds http-wise but the stored row doesn't change. done looks like this: one `POST /dev/orders` from inside the compose network with body `{"order_id":..., "merchant_id":..., "amount":...}` and within ~30s: - http 200 back - exactly one row in the `orders` table keyed by `order_id`, carrying merchant_id and amount - nothing in the dlq - re-POST the same body → still 200, still one row, unchanged - two different order_ids under the same merchant preserve posted order in the table timestamps shape of it: - rest api, stage `dev`, resource `/orders`, method `POST`. integration is a direct aws-service call to sqs , not AWS_PROXY, not a lambda proxy. api gateway assumes a role and hands the message straight to the queue. - the queue is fifo. content-based dedup off. a separate fifo dlq is wired via redrive. - a lambda consumes the queue via an event source mapping, writes to ddb, and reports per-record failures so a single bad record doesn't retry the whole batch. - ddb table `orders`, partition key `order_id` (String). also: api gateway is two-layer , there's the CONFIGURATION (resources, methods, integration, role, mapping templates) and there's the live STAGE that clients actually hit. editing configuration in place doesn't promote anything; clients keep seeing the old behavior until you create a NEW deployment for the stage. so after every wiring change, call `apigateway create-deployment` against this rest-api targeting stage `dev` , once at the very end, once after a fix, every time. forgetting this is the single most common reason an otherwise-correct setup still looks broken. names the verifier grabs by hand, use them exactly: | thing | name | |-|-| | rest api | `orders-api` | | stage | `dev` | | resource path | `/orders` | | method | `POST` | | main queue | `orders.fifo` | | dlq | `orders-dlq.fifo` | | apigw→sqs role | `apigw-to-sqs-role` | | consumer lambda | `orders-consumer` | | consumer lambda role | `orders-consumer-role` | | ddb table | `orders` (pk `order_id` String) | python3.11 for the lambda. the lambda runs on the shared compose network so `http://localstack:4566` is reachable from inside it. localstack community 4.13.1. you have up to 60 minutes.

List working directory

shell
ls -la /app/
output
total 16
drwxr-xr-x 1 root root 4096 Apr 23 01:22 .
drwxr-xr-x 1 root root 4096 Apr 28 14:02 ..
-rwxr-xr-x 1 root root 3782 Apr 23 01:22 setup.sh
drwxr-xr-x 2 root root 4096 Apr 23 01:22 starter

[stdout]
total 16
drwxr-xr-x 1 root root 4096 Apr 23 01:22 .
drwxr-xr-x 1 root root 4096 Apr 28 14:02 ..
-rwxr-xr-x 1 root root 3782 Apr 23 01:22 setup.sh
drwxr-xr-x 2 root root 4096 Apr 23 01:22 starter

Read setup script and starter

shell
cat /app/setup.sh && ls -la /app/starter/
output
#!/bin/bash
[redacted: decontamination sentinel]
[redacted: decontamination sentinel]
#
# Pre-seeds the consumer Lambda + its role with a broken-by-design
# handler and incomplete IAM. The agent has to build everything else
# (queues, DDB, apigw, integration, deployment, ESM) AND fix this
# Lambda's handler + role. Without the pre-seeded Lambda, Opus 4.7
# tends to read the prose and forget the consumer path entirely.

set -euo pipefail

REGION="${AWS_DEFAULT_REGION:-us-east-1}"
ACCOUNT_ID="000000000000"

LAMBDA_FUNC="orders-consumer"
LAMBDA_ROLE="orders-consumer-role"

log() { echo "[setup] $*" >&2; }

log "waiting for localstack"
for _ in $(seq 1 80); do
  HEALTH=$(curl -sf http://localstack:4566/_localstack/health || true)
  echo "$HEALTH" | grep -qE '"lambda": "(available|running)"' \
    && echo "$HEALTH" | grep -qE '"iam": "(available|running)"' \
    && break
  sleep 2
done

log "creating Lambda consumer role (deliberately incomplete)"
TRUST=$(cat <<'JSON'
{
  "Version": "2012-10-17",
  "Statement": [
    {"Effect": "Allow", "Principal": {"Service": "lambda.amazonaws.com"}, "Action": "sts:AssumeRole"}
  ]
}
JSON
)
aws iam create-role \
  --role-name "$LAMBDA_ROLE" \
  --assume-role-policy-document "$TRUST" >/dev/null
aws iam attach-role-policy \
  --role-name "$LAMBDA_ROLE" \
  --policy-arn arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
# Note: no dynamodb:PutItem, no sqs perms. Agent fixes this.
ROLE_ARN=$(aws iam get-role --role-name "$LAMBDA_ROLE" --query 'Role.Arn' --output text)

log "packaging Lambda (broken-by-design inline handler)"
WORKDIR="$(mktemp -d)"
cat > "${WORKDIR}/handler.py" <<'PY'
"""Orders consumer - broken by design.

Known issues (agent must fix):
  - Not idempotent: a duplicate message will try to PutItem again,
    which will either overwrite (wrong) or fail (wrong shape).
  - Returns a per-record 'failed' list instead of the AWS-required
    batchItemFailures shape for partial-batch-failure reporting.
"""

import json
import os
import time
import boto3

_endpoint = os.environ.get("AWS_ENDPOINT_URL", "http://localstack:4566")
ddb = boto3.client("dynamodb", endpoint_url=_endpoint)

TABLE_NAME = os.environ.get("TABLE_NAME", "orders")


def _process_record(record):
    payload = json.loads(record["body"])
    order_id = payload["order_id"]
    merchant_id = payload["merchant_id"]
    amount = int(payload["amount"])

    ddb.put_item(
        TableName=TABLE_NAME,
        Item={
            "order_id": {"S": order_id},
            "merchant_id": {"S": merchant_id},
            "amount": {"N": str(amount)},
            "created_at": {"N": str(int(time.time()))},
        },
    )


def lambda_handler(event, context):
    failed = []
    for record in event.get("Records", []):
        try:
            _process_record(record)
        except Exception as e:
            print(f"[error] msgId={record.get('messageId')} {type(e).__name__}: {e}")
            failed.append({"itemIdentifier": record["messageId"]})

    return {"failed": failed}
PY
(cd "$WORKDIR" && zip -q handler.zip handler.py)

log "creating Lambda function"
aws lambda create-function \
  --function-name "$LAMBDA_FUNC" \
  --runtime python3.11 \
  --role "$ROLE_ARN" \
  --handler handler.lambda_handler \
  --timeout 30 \
  --memory-size 512 \
  --environment "Variables={AWS_ENDPOINT_URL=http://localstack:4566,TABLE_NAME=orders}" \
  --zip-file "fileb://${WORKDIR}/handler.zip" >/dev/null

for _ in $(seq 1 30); do
  STATE=$(aws lambda get-function --function-name "$LAMBDA_FUNC" \
    --query 'Configuration.State' --output text 2>/dev/null || echo "Pending")
  [ "$STATE" = "Active" ] && break
  sleep 1
done
log "Lambda $LAMBDA_FUNC ready"

log "done"
total 12
drwxr-xr-x 2 root root 4096 Apr 23 01:22 .
drwxr-xr-x 1 root root 4096 Apr 23 01:22 ..
-rwxr-xr-x 1 root root 3782 Apr 23 01:19 setup.sh

[stdout]
#!/bin/bash
[redacted: decontamination sentinel]
[redacted: decontamination sentinel]
#
# Pre-seeds the consumer Lambda + its role with a broken-by-design
# handler and incomplete IAM. The agent has to build everything else
# (queues, DDB, apigw, integration, deployment, ESM) AND fix this
# Lambda's handler + role. Without the pre-seeded Lambda, Opus 4.7
# tends to read the prose and forget the consumer path entirely.

set -euo pipefail

REGION="${AWS_DEFAULT_REGION:-us-east-1}"
ACCOUNT_ID="000000000000"

LAMBDA_FUNC="orders-consumer"
LAMBDA_ROLE="orders-consumer-role"

log() { echo "[setup] $*" >&2; }

log "waiting for localstack"
for _ in $(seq 1 80); do
  HEALTH=$(curl -sf http://localstack:4566/_localstack/health || true)
  echo "$HEALTH" | grep -qE '"lambda": "(available|running)"' \
    && echo "$HEALTH" | grep -qE '"iam": "(available|running)"' \
    && break
  sleep 2
done

log "creating Lambda consumer role (deliberately incomplete)"
TRUST=$(cat <<'JSON'
{
  "Version": "2012-10-17",
  "Statement": [
    {"Effect": "Allow", "Principal": {"Service": "lambda.amazonaws.com"}, "Action": "sts:AssumeRole"}
  ]
}
JSON
)
aws iam create-role \
  --role-name "$LAMBDA_ROLE" \
  --assume-role-policy-document "$TRUST" >/dev/null
aws iam attach-role-policy \
  --role-name "$LAMBDA_ROLE" \
  --policy-arn arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
# Note: no dynamodb:PutItem, no sqs perms. Agent fixes this.
ROLE_ARN=$(aws iam get-role --role-name "$LAMBDA_ROLE" --query 'Role.Arn' --output text)

log "packaging Lambda (broken-by-design inline handler)"
WORKDIR="$(mktemp -d)"
cat > "${WORKDIR}/handler.py" <<'PY'
"""Orders consumer - broken by design.

Known issues (agent must fix):
  - Not idempotent: a duplicate message will try to PutItem again,
    which will either overwrite (wrong) or fail (wrong shape).
  - Returns a per-record 'failed' list instead of the AWS-required
    batchItemFailures shape for partial-batch-failure reporting.
"""

import json
import os
import time
import boto3

_endpoint = os.environ.get("AWS_ENDPOINT_URL", "http://localstack:4566")
ddb = boto3.client("dynamodb", endpoint_url=_endpoint)

TABLE_NAME = os.environ.get("TABLE_NAME", "orders")


def _process_record(record):
    payload = json.loads(record["body"])
    order_id = payload["order_id"]
    merchant_id = payload["merchant_id"]
    amount = int(payload["amount"])

    ddb.put_item(
        TableName=TABLE_NAME,
        Item={
            "order_id": {"S": order_id},
            "merchant_id": {"S": merchant_id},
            "amount": {"N": str(amount)},
            "created_at": {"N": str(int(time.time()))},
        },
    )


def lambda_handler(event, context):
    failed = []
    for record in event.get("Records", []):
        try:
            _process_record(record)
        except Exception as e:
            print(f"[error] msgId={record.get('messageId')} {type(e).__name__}: {e}")
            failed.append({"itemIdentifier": record["messageId"]})

    return {"failed": failed}
PY
(cd "$WORKDIR" && zip -q handler.zip handler.py)

log "creating Lambda function"
aws lambda create-function \
  --function-name "$LAMBDA_FUNC" \
  --runtime python3.11 \
  --role "$ROLE_ARN" \
  --handler handler.lambda_handler \
  --timeout 30 \
  --memory-size 512 \
  --environment "Variables={AWS_ENDPOINT_URL=http://localstack:4566,TABLE_NAME=orders}" \
  --zip-file "fileb://${WORKDIR}/handler.zip" >/dev/null

for _ in $(seq 1 30); do
  STATE=$(aws lambda get-function --function-name "$LAMBDA_FUNC" \
    --query 'Configuration.State' --output text 2>/dev/null || echo "Pending")
  [ "$STATE" = "Active" ] && break
  sleep 1
done
log "Lambda $LAMBDA_FUNC ready"

log "done"
total 12
drwxr-xr-x 2 root root 4096 Apr 23 01:22 .
drwxr-xr-x 1 root root 4096 Apr 23 01:22 ..
-rwxr-xr-x 1 root root 3782 Apr 23 01:19 setup.sh
I'll start by checking the current state of pre-seeded items, then build out everything in parallel where possible.

Inspect pre-seeded resources

shell
aws --endpoint-url=http://localstack:4566 lambda get-function --function-name orders-consumer --query '{State:Configuration.State,Role:Configuration.Role,Handler:Configuration.Handler,Env:Configuration.Environment.Variables}' 2>&1
echo "---"
aws iam get-role --role-name orders-consumer-role --query 'Role.Arn' --output text 2>&1
echo "---"
aws iam list-attached-role-policies --role-name orders-consumer-role 2>&1
echo "---"
aws iam list-role-policies --role-name orders-consumer-role 2>&1
output
{
    "State": "Active",
    "Role": "arn:aws:iam::000000000000:role/orders-consumer-role",
    "Handler": "handler.lambda_handler",
    "Env": {
        "AWS_ENDPOINT_URL": "http://localstack:4566",
        "TABLE_NAME": "orders"
    }
}
---
arn:aws:iam::000000000000:role/orders-consumer-role
---
{
    "AttachedPolicies": [
        {
            "PolicyName": "AWSLambdaBasicExecutionRole",
            "PolicyArn": "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
        }
    ]
}
---
{
    "PolicyNames": []
}

[stdout]
{
    "State": "Active",
    "Role": "arn:aws:iam::000000000000:role/orders-consumer-role",
    "Handler": "handler.lambda_handler",
    "Env": {
        "AWS_ENDPOINT_URL": "http://localstack:4566",
        "TABLE_NAME": "orders"
    }
}
---
arn:aws:iam::000000000000:role/orders-consumer-role
---
{
    "AttachedPolicies": [
        {
            "PolicyName": "AWSLambdaBasicExecutionRole",
            "PolicyArn": "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
        }
    ]
}
---
{
    "PolicyNames": []
}

Check AWS env config

shell
env | grep -iE 'aws|endpoint' | sort
echo "---"
cat ~/.aws/config 2>/dev/null || echo "no aws config"
echo "---"
aws iam get-role --role-name orders-consumer-role --query 'Role.Arn' --output text 2>&1 | head -20
output
AWS_ACCESS_KEY_ID=test
AWS_DEFAULT_REGION=us-east-1
AWS_ENDPOINT_URL=http://localstack:4566
AWS_PAGER=
AWS_SECRET_ACCESS_KEY=test
---
no aws config
---
arn:aws:iam::000000000000:role/orders-consumer-role

[stdout]
AWS_ACCESS_KEY_ID=test
AWS_DEFAULT_REGION=us-east-1
AWS_ENDPOINT_URL=http://localstack:4566
AWS_PAGER=
AWS_SECRET_ACCESS_KEY=test
---
no aws config
---
arn:aws:iam::000000000000:role/orders-consumer-role
Good , env is set. Building everything now.

Create DDB orders table

shell
aws dynamodb create-table \
  --table-name orders \
  --attribute-definitions AttributeName=order_id,AttributeType=S \
  --key-schema AttributeName=order_id,KeyType=HASH \
  --billing-mode PAY_PER_REQUEST 2>&1 | head -30
output
{
    "TableDescription": {
        "AttributeDefinitions": [
            {
                "AttributeName": "order_id",
                "AttributeType": "S"
            }
        ],
        "TableName": "orders",
        "KeySchema": [
            {
                "AttributeName": "order_id",
                "KeyType": "HASH"
            }
        ],
        "TableStatus": "ACTIVE",
        "CreationDateTime": "2026-04-28T14:05:06.065000+00:00",
        "ProvisionedThroughput": {
            "LastIncreaseDateTime": "1970-01-01T00:00:00+00:00",
            "LastDecreaseDateTime": "1970-01-01T00:00:00+00:00",
            "NumberOfDecreasesToday": 0,
            "ReadCapacityUnits": 0,
            "WriteCapacityUnits": 0
        },
        "TableSizeBytes": 0,
        "ItemCount": 0,
        "TableArn": "arn:aws:dynamodb:us-east-1:000000000000:table/orders",
        "TableId": "5600e83d-f70f-47b9-ae02-ef84bf08e56c",
        "BillingModeSummary": {
            "BillingMode": "PAY_PER_REQUEST",

[stdout]
{
    "TableDescription": {
        "AttributeDefinitions": [
            {
                "AttributeName": "order_id",
                "AttributeType": "S"
            }
        ],
        "TableName": "orders",
        "KeySchema": [
            {
                "AttributeName": "order_id",
                "KeyType": "HASH"
            }
        ],
        "TableStatus": "ACTIVE",
        "CreationDateTime": "2026-04-28T14:05:06.065000+00:00",
        "ProvisionedThroughput": {
            "LastIncreaseDateTime": "1970-01-01T00:00:00+00:00",
            "LastDecreaseDateTime": "1970-01-01T00:00:00+00:00",
            "NumberOfDecreasesToday": 0,
            "ReadCapacityUnits": 0,
            "WriteCapacityUnits": 0
        },
        "TableSizeBytes": 0,
        "ItemCount": 0,
        "TableArn": "arn:aws:dynamodb:us-east-1:000000000000:table/orders",
        "TableId": "5600e83d-f70f-47b9-ae02-ef84bf08e56c",
        "BillingModeSummary": {
            "BillingMode": "PAY_PER_REQUEST",

Create FIFO queues with redrive

shell
aws sqs create-queue \
  --queue-name orders-dlq.fifo \
  --attributes 'FifoQueue=true,ContentBasedDeduplication=false' 2>&1
echo "---"
DLQ_ARN=$(aws sqs get-queue-attributes --queue-url http://localstack:4566/000000000000/orders-dlq.fifo --attribute-names QueueArn --query 'Attributes.QueueArn' --output text)
echo "DLQ_ARN=$DLQ_ARN"
echo "---"
REDRIVE="{\"deadLetterTargetArn\":\"$DLQ_ARN\",\"maxReceiveCount\":\"5\"}"
aws sqs create-queue \
  --queue-name orders.fifo \
  --attributes "FifoQueue=true,ContentBasedDeduplication=false,RedrivePolicy=$(echo "$REDRIVE" | python3 -c 'import json,sys; s=sys.stdin.read().strip(); print(json.dumps(s))' )" 2>&1
echo "---"
aws sqs get-queue-attributes --queue-url http://localstack:4566/000000000000/orders.fifo --attribute-names All --query 'Attributes.{Fifo:FifoQueue,Dedup:ContentBasedDeduplication,Redrive:RedrivePolicy,Arn:QueueArn}' 2>&1
output
{
    "QueueUrl": "http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders-dlq.fifo"
}
---
DLQ_ARN=arn:aws:sqs:us-east-1:000000000000:orders-dlq.fifo
---
{
    "QueueUrl": "http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders.fifo"
}
---
{
    "Fifo": "true",
    "Dedup": "false",
    "Redrive": "{\"deadLetterTargetArn\":\"arn:aws:sqs:us-east-1:000000000000:orders-dlq.fifo\",\"maxReceiveCount\":\"5\"}",
    "Arn": "arn:aws:sqs:us-east-1:000000000000:orders.fifo"
}

[stdout]
{
    "QueueUrl": "http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders-dlq.fifo"
}
---
DLQ_ARN=arn:aws:sqs:us-east-1:000000000000:orders-dlq.fifo
---
{
    "QueueUrl": "http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders.fifo"
}
---
{
    "Fifo": "true",
    "Dedup": "false",
    "Redrive": "{\"deadLetterTargetArn\":\"arn:aws:sqs:us-east-1:000000000000:orders-dlq.fifo\",\"maxReceiveCount\":\"5\"}",
    "Arn": "arn:aws:sqs:us-east-1:000000000000:orders.fifo"
}
Queues created with redrive. Now the consumer role policy and the fixed handler.

Add SQS+DDB perms to consumer role

shell
cat > /tmp/consumer-policy.json <<'JSON'
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "sqs:ReceiveMessage",
        "sqs:DeleteMessage",
        "sqs:GetQueueAttributes",
        "sqs:ChangeMessageVisibility"
      ],
      "Resource": "arn:aws:sqs:us-east-1:000000000000:orders.fifo"
    },
    {
      "Effect": "Allow",
      "Action": [
        "dynamodb:PutItem",
        "dynamodb:GetItem",
        "dynamodb:UpdateItem",
        "dynamodb:DescribeTable"
      ],
      "Resource": "arn:aws:dynamodb:us-east-1:000000000000:table/orders"
    }
  ]
}
JSON
aws iam put-role-policy \
  --role-name orders-consumer-role \
  --policy-name orders-consumer-inline \
  --policy-document file:///tmp/consumer-policy.json
echo "consumer role policy attached"
output
consumer role policy attached

[stdout]
consumer role policy attached

Fix and deploy lambda handler

shell
mkdir -p /tmp/lambda
cat > /tmp/lambda/handler.py <<'PY'
import json
import os
import time
import boto3
from botocore.exceptions import ClientError

_endpoint = os.environ.get("AWS_ENDPOINT_URL", "http://localstack:4566")
ddb = boto3.client("dynamodb", endpoint_url=_endpoint)

TABLE_NAME = os.environ.get("TABLE_NAME", "orders")


def _process_record(record):
    payload = json.loads(record["body"])
    order_id = payload["order_id"]
    merchant_id = payload["merchant_id"]
    amount = int(payload["amount"])

    try:
        ddb.put_item(
            TableName=TABLE_NAME,
            Item={
                "order_id": {"S": order_id},
                "merchant_id": {"S": merchant_id},
                "amount": {"N": str(amount)},
                "created_at": {"N": str(int(time.time() * 1000))},
            },
            ConditionExpression="attribute_not_exists(order_id)",
        )
    except ClientError as e:
        if e.response["Error"]["Code"] == "ConditionalCheckFailedException":
            print(f"[skip-duplicate] order_id={order_id}")
            return
        raise


def lambda_handler(event, context):
    batch_item_failures = []
    for record in event.get("Records", []):
        try:
            _process_record(record)
        except Exception as e:
            print(f"[error] msgId={record.get('messageId')} {type(e).__name__}: {e}")
            batch_item_failures.append({"itemIdentifier": record["messageId"]})

    return {"batchItemFailures": batch_item_failures}
PY

(cd /tmp/lambda && zip -q handler.zip handler.py)
aws lambda update-function-code \
  --function-name orders-consumer \
  --zip-file fileb:///tmp/lambda/handler.zip \
  --query '{State:State,LastUpdateStatus:LastUpdateStatus}' 2>&1

for i in $(seq 1 30); do
  s=$(aws lambda get-function-configuration --function-name orders-consumer --query 'LastUpdateStatus' --output text 2>/dev/null)
  [ "$s" = "Successful" ] && break
  sleep 1
done
echo "lambda update status: $s"
output
{
    "State": "Active",
    "LastUpdateStatus": "InProgress"
}
lambda update status: Successful

[stdout]
{
    "State": "Active",
    "LastUpdateStatus": "InProgress"
}
lambda update status: Successful

Wire SQS to lambda

shell
aws lambda create-event-source-mapping \
  --function-name orders-consumer \
  --event-source-arn arn:aws:sqs:us-east-1:000000000000:orders.fifo \
  --batch-size 10 \
  --function-response-types ReportBatchItemFailures 2>&1
echo "---"
for i in $(seq 1 20); do
  state=$(aws lambda list-event-source-mappings --function-name orders-consumer --query 'EventSourceMappings[0].State' --output text 2>/dev/null)
  [ "$state" = "Enabled" ] && break
  sleep 1
done
echo "ESM state: $state"
output
{
    "UUID": "480d4958-216f-4ab7-a2a5-0e84f9796d09",
    "BatchSize": 10,
    "MaximumBatchingWindowInSeconds": 0,
    "EventSourceArn": "arn:aws:sqs:us-east-1:000000000000:orders.fifo",
    "FunctionArn": "arn:aws:lambda:us-east-1:000000000000:function:orders-consumer",
    "LastModified": "2026-04-28T14:05:53.867969+00:00",
    "State": "Creating",
    "StateTransitionReason": "USER_INITIATED",
    "FunctionResponseTypes": [
        "ReportBatchItemFailures"
    ],
    "EventSourceMappingArn": "arn:aws:lambda:us-east-1:000000000000:event-source-mapping:480d4958-216f-4ab7-a2a5-0e84f9796d09"
}
---
ESM state: Enabled

[stdout]
{
    "UUID": "480d4958-216f-4ab7-a2a5-0e84f9796d09",
    "BatchSize": 10,
    "MaximumBatchingWindowInSeconds": 0,
    "EventSourceArn": "arn:aws:sqs:us-east-1:000000000000:orders.fifo",
    "FunctionArn": "arn:aws:lambda:us-east-1:000000000000:function:orders-consumer",
    "LastModified": "2026-04-28T14:05:53.867969+00:00",
    "State": "Creating",
    "StateTransitionReason": "USER_INITIATED",
    "FunctionResponseTypes": [
        "ReportBatchItemFailures"
    ],
    "EventSourceMappingArn": "arn:aws:lambda:us-east-1:000000000000:event-source-mapping:480d4958-216f-4ab7-a2a5-0e84f9796d09"
}
---
ESM state: Enabled
Now the apigw→sqs role and the REST API.

Create apigw→sqs role + policy

shell
cat > /tmp/apigw-trust.json <<'JSON'
{
  "Version": "2012-10-17",
  "Statement": [
    {"Effect": "Allow", "Principal": {"Service": "apigateway.amazonaws.com"}, "Action": "sts:AssumeRole"}
  ]
}
JSON
aws iam create-role \
  --role-name apigw-to-sqs-role \
  --assume-role-policy-document file:///tmp/apigw-trust.json \
  --query 'Role.Arn' --output text

cat > /tmp/apigw-policy.json <<'JSON'
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": ["sqs:SendMessage", "sqs:GetQueueUrl", "sqs:GetQueueAttributes"],
      "Resource": "arn:aws:sqs:us-east-1:000000000000:orders.fifo"
    },
    {
      "Effect": "Allow",
      "Action": ["logs:CreateLogGroup","logs:CreateLogStream","logs:PutLogEvents"],
      "Resource": "*"
    }
  ]
}
JSON
aws iam put-role-policy \
  --role-name apigw-to-sqs-role \
  --policy-name apigw-to-sqs-inline \
  --policy-document file:///tmp/apigw-policy.json
echo "apigw role done"
output
arn:aws:iam::000000000000:role/apigw-to-sqs-role
apigw role done

[stdout]
arn:aws:iam::000000000000:role/apigw-to-sqs-role
apigw role done

Create REST API and /orders resource

shell
API_ID=$(aws apigateway create-rest-api --name orders-api --query 'id' --output text)
echo "API_ID=$API_ID"
ROOT_ID=$(aws apigateway get-resources --rest-api-id "$API_ID" --query 'items[?path==`/`].id' --output text)
echo "ROOT_ID=$ROOT_ID"
RES_ID=$(aws apigateway create-resource --rest-api-id "$API_ID" --parent-id "$ROOT_ID" --path-part orders --query 'id' --output text)
echo "RES_ID=$RES_ID"
echo "$API_ID" > /tmp/api_id
echo "$RES_ID" > /tmp/res_id
output
API_ID=rmugrwhqen
ROOT_ID=q7jhe1bxh8
RES_ID=le20kaao5p

[stdout]
API_ID=rmugrwhqen
ROOT_ID=q7jhe1bxh8
RES_ID=le20kaao5p

Create POST method + AWS-service integration to SQS

shell
API_ID=$(cat /tmp/api_id)
RES_ID=$(cat /tmp/res_id)

aws apigateway put-method \
  --rest-api-id "$API_ID" \
  --resource-id "$RES_ID" \
  --http-method POST \
  --authorization-type NONE \
  --query '{HttpMethod:httpMethod,Auth:authorizationType}' 2>&1

# Mapping template: SendMessage with order_id as dedup, merchant_id as group
TEMPLATE='Action=SendMessage&MessageBody=$util.urlEncode($input.body)&MessageGroupId=$util.urlEncode($input.path('"'"'$.merchant_id'"'"'))&MessageDeduplicationId=$util.urlEncode($input.path('"'"'$.order_id'"'"'))'

cat > /tmp/req-templates.json <<JSON
{"application/json": "$TEMPLATE"}
JSON

aws apigateway put-integration \
  --rest-api-id "$API_ID" \
  --resource-id "$RES_ID" \
  --http-method POST \
  --type AWS \
  --integration-http-method POST \
  --uri "arn:aws:apigateway:us-east-1:sqs:path/000000000000/orders.fifo" \
  --credentials "arn:aws:iam::000000000000:role/apigw-to-sqs-role" \
  --request-parameters 'integration.request.header.Content-Type=$util.urlEncode('"'"'application/x-www-form-urlencoded'"'"')' \
  --request-templates file:///tmp/req-templates.json \
  --passthrough-behavior NEVER \
  --query '{Type:type,Uri:uri}' 2>&1
output
Exit code 252
{
    "HttpMethod": "POST",
    "Auth": "NONE"
}

aws: [ERROR]: An error occurred (ParamValidation): Error parsing parameter '--request-parameters': Expected: ',', received: ''' for input:
 integration.request.header.Content-Type=$util.urlEncode('application/x-www-form-urlencoded')
                                                        ^

[error] tool reported failure

Put integration with proper JSON params

shell
API_ID=$(cat /tmp/api_id)
RES_ID=$(cat /tmp/res_id)

cat > /tmp/req-params.json <<'JSON'
{"integration.request.header.Content-Type": "'application/x-www-form-urlencoded'"}
JSON

cat > /tmp/req-templates.json <<'JSON'
{"application/json": "Action=SendMessage&MessageBody=$util.urlEncode($input.body)&MessageGroupId=$util.urlEncode($input.path('$.merchant_id'))&MessageDeduplicationId=$util.urlEncode($input.path('$.order_id'))"}
JSON

aws apigateway put-integration \
  --rest-api-id "$API_ID" \
  --resource-id "$RES_ID" \
  --http-method POST \
  --type AWS \
  --integration-http-method POST \
  --uri "arn:aws:apigateway:us-east-1:sqs:path/000000000000/orders.fifo" \
  --credentials "arn:aws:iam::000000000000:role/apigw-to-sqs-role" \
  --request-parameters file:///tmp/req-params.json \
  --request-templates file:///tmp/req-templates.json \
  --passthrough-behavior NEVER \
  --query '{Type:type,Uri:uri,Creds:credentials}' 2>&1
output
{
    "Type": "AWS",
    "Uri": "arn:aws:apigateway:us-east-1:sqs:path/000000000000/orders.fifo",
    "Creds": "arn:aws:iam::000000000000:role/apigw-to-sqs-role"
}

[stdout]
{
    "Type": "AWS",
    "Uri": "arn:aws:apigateway:us-east-1:sqs:path/000000000000/orders.fifo",
    "Creds": "arn:aws:iam::000000000000:role/apigw-to-sqs-role"
}

Method+integration response, deploy to dev

shell
API_ID=$(cat /tmp/api_id)
RES_ID=$(cat /tmp/res_id)

aws apigateway put-method-response \
  --rest-api-id "$API_ID" \
  --resource-id "$RES_ID" \
  --http-method POST \
  --status-code 200 \
  --response-models '{"application/json":"Empty"}' \
  --query '{Status:statusCode}' 2>&1

cat > /tmp/int-resp-templates.json <<'JSON'
{"application/json": "{\"ok\":true}"}
JSON

aws apigateway put-integration-response \
  --rest-api-id "$API_ID" \
  --resource-id "$RES_ID" \
  --http-method POST \
  --status-code 200 \
  --selection-pattern "" \
  --response-templates file:///tmp/int-resp-templates.json \
  --query '{Status:statusCode}' 2>&1

aws apigateway create-deployment \
  --rest-api-id "$API_ID" \
  --stage-name dev \
  --query '{Id:id,CreatedDate:createdDate}' 2>&1
output
{
    "Status": "200"
}
{
    "Status": "200"
}
{
    "Id": "zgi9wvxnej",
    "CreatedDate": "2026-04-28T14:06:38+00:00"
}

[stdout]
{
    "Status": "200"
}
{
    "Status": "200"
}
{
    "Id": "zgi9wvxnej",
    "CreatedDate": "2026-04-28T14:06:38+00:00"
}
Deployed. Let me run the end-to-end tests now.

Test single POST end-to-end

shell
API_ID=$(cat /tmp/api_id)
URL="http://localstack:4566/restapis/${API_ID}/dev/_user_request_/orders"
echo "POST URL: $URL"
echo "--- POST 1 ---"
curl -s -o /tmp/r1.json -w "HTTP %{http_code}\n" -X POST -H "Content-Type: application/json" -d '{"order_id":"o-100","merchant_id":"m-A","amount":4200}' "$URL"
cat /tmp/r1.json; echo
echo "--- waiting for consumer ---"
sleep 6
aws dynamodb scan --table-name orders --query 'Items' 2>&1
echo "--- DLQ depth ---"
aws sqs get-queue-attributes --queue-url http://localstack:4566/000000000000/orders-dlq.fifo --attribute-names ApproximateNumberOfMessages --query 'Attributes' 2>&1
output
POST URL: http://localstack:4566/restapis/rmugrwhqen/dev/_user_request_/orders
--- POST 1 ---
HTTP 200
{"ok":true}
--- waiting for consumer ---
[
    {
        "created_at": {
            "N": "1777385211635"
        },
        "amount": {
            "N": "4200"
        },
        "merchant_id": {
            "S": "m-A"
        },
        "order_id": {
            "S": "o-100"
        }
    }
]
--- DLQ depth ---
{
    "ApproximateNumberOfMessages": "0"
}

[stdout]
POST URL: http://localstack:4566/restapis/rmugrwhqen/dev/_user_request_/orders
--- POST 1 ---
HTTP 200
{"ok":true}
--- waiting for consumer ---
[
    {
        "created_at": {
            "N": "1777385211635"
        },
        "amount": {
            "N": "4200"
        },
        "merchant_id": {
            "S": "m-A"
        },
        "order_id": {
            "S": "o-100"
        }
    }
]
--- DLQ depth ---
{
    "ApproximateNumberOfMessages": "0"
}

Test duplicate POST is no-op

shell
API_ID=$(cat /tmp/api_id)
URL="http://localstack:4566/restapis/${API_ID}/dev/_user_request_/orders"

echo "--- DUPLICATE POST (same order_id=o-100) ---"
curl -s -o /tmp/r2.json -w "HTTP %{http_code}\n" -X POST -H "Content-Type: application/json" -d '{"order_id":"o-100","merchant_id":"m-A","amount":9999}' "$URL"
cat /tmp/r2.json; echo
sleep 5
echo "--- table state (should still be one row, amount=4200, same created_at) ---"
aws dynamodb scan --table-name orders --query 'Items' 2>&1
echo "--- DLQ depth (should be 0) ---"
aws sqs get-queue-attributes --queue-url http://localstack:4566/000000000000/orders-dlq.fifo --attribute-names ApproximateNumberOfMessages --query 'Attributes' 2>&1
output
--- DUPLICATE POST (same order_id=o-100) ---
HTTP 200
{"ok":true}
--- table state (should still be one row, amount=4200, same created_at) ---
[
    {
        "created_at": {
            "N": "1777385211635"
        },
        "amount": {
            "N": "4200"
        },
        "merchant_id": {
            "S": "m-A"
        },
        "order_id": {
            "S": "o-100"
        }
    }
]
--- DLQ depth (should be 0) ---
{
    "ApproximateNumberOfMessages": "0"
}

[stdout]
--- DUPLICATE POST (same order_id=o-100) ---
HTTP 200
{"ok":true}
--- table state (should still be one row, amount=4200, same created_at) ---
[
    {
        "created_at": {
            "N": "1777385211635"
        },
        "amount": {
            "N": "4200"
        },
        "merchant_id": {
            "S": "m-A"
        },
        "order_id": {
            "S": "o-100"
        }
    }
]
--- DLQ depth (should be 0) ---
{
    "ApproximateNumberOfMessages": "0"
}

Verify FIFO ordering preserves timestamps

shell
API_ID=$(cat /tmp/api_id)
URL="http://localstack:4566/restapis/${API_ID}/dev/_user_request_/orders"

echo "--- two orders under m-B in sequence ---"
curl -s -o /dev/null -w "HTTP %{http_code}\n" -X POST -H "Content-Type: application/json" -d '{"order_id":"o-201","merchant_id":"m-B","amount":100}' "$URL"
sleep 1
curl -s -o /dev/null -w "HTTP %{http_code}\n" -X POST -H "Content-Type: application/json" -d '{"order_id":"o-202","merchant_id":"m-B","amount":200}' "$URL"
sleep 6

echo "--- table state ---"
aws dynamodb scan --table-name orders --query 'Items[?merchant_id.S==`m-B`].{oid:order_id.S,ts:created_at.N,amt:amount.N}' --output table 2>&1
echo "--- DLQ ---"
aws sqs get-queue-attributes --queue-url http://localstack:4566/000000000000/orders-dlq.fifo --attribute-names ApproximateNumberOfMessages --query 'Attributes' 2>&1
output
--- two orders under m-B in sequence ---
HTTP 200
HTTP 200
--- table state ---
-----------------------------------
|              Scan               |
+-----+---------+-----------------+
| amt |   oid   |       ts        |
+-----+---------+-----------------+
|  100|  o-201  |  1777385236721  |
|  200|  o-202  |  1777385239064  |
+-----+---------+-----------------+
--- DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}

[stdout]
--- two orders under m-B in sequence ---
HTTP 200
HTTP 200
--- table state ---
-----------------------------------
|              Scan               |
+-----+---------+-----------------+
| amt |   oid   |       ts        |
+-----+---------+-----------------+
|  100|  o-201  |  1777385236721  |
|  200|  o-202  |  1777385239064  |
+-----+---------+-----------------+
--- DLQ ---
{
    "ApproximateNumberOfMessages": "0"
}
All criteria pass: - **POST single order** → HTTP 200, one row in `orders` keyed by `order_id` with merchant_id and amount, DLQ empty - **Duplicate POST** → HTTP 200, table still has exactly one row with the original `created_at` (idempotent at storage layer via `attribute_not_exists(order_id)` ConditionExpression) - **Two orders under same merchant** → both stored, `created_at` timestamps preserve POST order (FIFO via `MessageGroupId=merchant_id`), DLQ empty What was built: - **DDB** `orders` (pk `order_id` String) - **FIFO queues** `orders.fifo` + `orders-dlq.fifo` with redrive (maxReceiveCount=5), content-based dedup OFF - **Lambda role** , added `dynamodb:PutItem/GetItem/UpdateItem/DescribeTable` and `sqs:ReceiveMessage/DeleteMessage/GetQueueAttributes/ChangeMessageVisibility` - **Lambda handler fixes** , returns `batchItemFailures` (correct partial-failure shape), idempotent via `ConditionExpression="attribute_not_exists(order_id)"` swallowing `ConditionalCheckFailedException` - **Event source mapping** main queue → consumer with `ReportBatchItemFailures` - **apigw→sqs role** `apigw-to-sqs-role` with `sqs:SendMessage` on the main queue - **REST API** `orders-api`, resource `/orders`, `POST` with type `AWS` (not AWS_PROXY) integration to `sqs:path/000000000000/orders.fifo`, mapping template builds `Action=SendMessage&MessageBody=...&MessageGroupId=merchant_id&MessageDeduplicationId=order_id`, integration response template returns `{"ok":true}` - **Deployment** to stage `dev`
Final diff , what the agent changed

No file changes, the agent left the workspace untouched.

Verifier output , the proof behind the reward
tests/test.sh
============================= test session starts ==============================
platform linux -- Python 3.12.3, pytest-8.4.1, pluggy-1.6.0 -- /root/.cache/uv/archive-v0/Frgu0E8AyecaV4ayPNu70/bin/python
cachedir: .pytest_cache
rootdir: /tests
plugins: json-ctrf-0.3.5
collecting ... collected 19 items

../tests/test_outputs.py::test_localstack_reachable PASSED               [  5%]
../tests/test_outputs.py::test_main_fifo_queue_exists PASSED             [ 10%]
../tests/test_outputs.py::test_dlq_fifo_queue_exists PASSED              [ 15%]
../tests/test_outputs.py::test_ddb_table_exists PASSED                   [ 21%]
../tests/test_outputs.py::test_lambda_and_esm_exist PASSED               [ 26%]
../tests/test_outputs.py::test_rest_api_exists_with_post_orders PASSED   [ 31%]
../tests/test_outputs.py::test_integration_uri_targets_fifo_queue PASSED [ 36%]
../tests/test_outputs.py::test_integration_credentials_role_is_set PASSED [ 42%]
../tests/test_outputs.py::test_integration_sets_content_type_header PASSED [ 47%]
../tests/test_outputs.py::test_integration_request_template_uses_full_body PASSED [ 52%]
../tests/test_outputs.py::test_integration_request_template_has_message_group_id PASSED [ 57%]
../tests/test_outputs.py::test_integration_request_template_has_dedup_id PASSED [ 63%]
../tests/test_outputs.py::test_integration_template_identifiers_are_request_derived PASSED [ 68%]
../tests/test_outputs.py::test_stage_deployment_id_was_refreshed FAILED  [ 73%]
../tests/test_outputs.py::test_event_source_mapping_declares_report_batch_item_failures PASSED [ 78%]
../tests/test_outputs.py::test_lambda_handler_idempotency_and_response_shape PASSED [ 84%]
../tests/test_outputs.py::test_end_to_end_post_reaches_ddb_no_dlq PASSED [ 89%]
../tests/test_outputs.py::test_end_to_end_fifo_group_ordering PASSED     [ 94%]
../tests/test_outputs.py::test_end_to_end_duplicate_post_is_idempotent PASSED [100%]

=================================== FAILURES ===================================
____________________ test_stage_deployment_id_was_refreshed ____________________

apigw = <botocore.client.APIGateway object at 0xffffa305db50>

    def test_stage_deployment_id_was_refreshed(apigw):
        """Stage redeployed after edit."""
        api_id = _find_api(apigw)
        stage = apigw.get_stage(restApiId=api_id, stageName=STAGE_NAME)
        current_dep_id = stage.get("deploymentId")
        assert current_dep_id, f"stage {STAGE_NAME} has no deploymentId"
        deployments = sorted(
            apigw.get_deployments(restApiId=api_id).get("items", []),
            key=lambda d: d.get("createdDate") or "",
        )
>       assert len(deployments) >= 2, (
            f"stage {STAGE_NAME} has only {len(deployments)} deployment(s); "
            f"editing an integration without calling create-deployment is "
            f"the #1 silent failure mode for this task , API Gateway keeps "
            f"serving the old snapshot. Deployments: {deployments!r}"
        )
E       AssertionError: stage dev has only 1 deployment(s); editing an integration without calling create-deployment is the #1 silent failure mode for this task , API Gateway keeps serving the old snapshot. Deployments: [{'id': 'zgi9wvxnej', 'createdDate': datetime.datetime(2026, 4, 28, 14, 6, 38, tzinfo=tzlocal())}]
E       assert 1 >= 2
E        +  where 1 = len([{'createdDate': datetime.datetime(2026, 4, 28, 14, 6, 38, tzinfo=tzlocal()), 'id': 'zgi9wvxnej'}])

/tests/test_outputs.py:350: AssertionError
=============================== warnings summary ===============================
test_outputs.py: 64 warnings
  /root/.cache/uv/archive-v0/Frgu0E8AyecaV4ayPNu70/lib/python3.12/site-packages/botocore/auth.py:424: DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.now(datetime.UTC).
    datetime_now = datetime.datetime.utcnow()

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
==================================== PASSES ====================================
=========================== short test summary info ============================
PASSED ../tests/test_outputs.py::test_localstack_reachable
PASSED ../tests/test_outputs.py::test_main_fifo_queue_exists
PASSED ../tests/test_outputs.py::test_dlq_fifo_queue_exists
PASSED ../tests/test_outputs.py::test_ddb_table_exists
PASSED ../tests/test_outputs.py::test_lambda_and_esm_exist
PASSED ../tests/test_outputs.py::test_rest_api_exists_with_post_orders
PASSED ../tests/test_outputs.py::test_integration_uri_targets_fifo_queue
PASSED ../tests/test_outputs.py::test_integration_credentials_role_is_set
PASSED ../tests/test_outputs.py::test_integration_sets_content_type_header
PASSED ../tests/test_outputs.py::test_integration_request_template_uses_full_body
PASSED ../tests/test_outputs.py::test_integration_request_template_has_message_group_id
PASSED ../tests/test_outputs.py::test_integration_request_template_has_dedup_id
PASSED ../tests/test_outputs.py::test_integration_template_identifiers_are_request_derived
PASSED ../tests/test_outputs.py::test_event_source_mapping_declares_report_batch_item_failures
PASSED ../tests/test_outputs.py::test_lambda_handler_idempotency_and_response_shape
PASSED ../tests/test_outputs.py::test_end_to_end_post_reaches_ddb_no_dlq
PASSED ../tests/test_outputs.py::test_end_to_end_fifo_group_ordering
PASSED ../tests/test_outputs.py::test_end_to_end_duplicate_post_is_idempotent
FAILED ../tests/test_outputs.py::test_stage_deployment_id_was_refreshed - Ass...
================== 1 failed, 18 passed, 64 warnings in 22.28s ==================

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_5670bc8ed12c4718. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_5670bc8ed12c4718 · verifier authoritative; classifier explanatory.