SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

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 output shows: `test_stage_deployment_id_was_refreshed FAILED` with message: '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': 'kxo71cai3c', ...}]' (lines 43-51 of verifier/test-stdout.txt). The agent created a REST API and called create-deployment once at the end but the test requires at least 2 deployments, indicating the agent should have called create-deployment multiple times after each integration configuration change, as emphasized in instruction.md lines 31-33: 'forgetting this is the single most common reason an otherwise-correct setup still looks broken.'
Root causeThe agent completed 18/19 tests successfully, including all end-to-end functional tests (dedup, ordering, no DLQ), but missed the API Gateway deployment refresh requirement. The instruction explicitly warns that deployment must be called 'after every wiring change' and lists this as the '#1 silent failure mode,' but the agent only created one deployment at the end rather than after each integration modification.
RecommendationN/A - task is fine. The instruction is clear and correctly specifies the API Gateway two-layer model. The test appropriately validates this critical requirement by counting deployments. The agent failed due to incomplete understanding of the deployment refresh frequency requirement, not due to ambiguous specification.
Trajectory
Tool-by-tool agent trajectory
23 tool calls · 3 tool types · 32 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.
ToolSearch
{
  "query": "select:TodoWrite",
  "max_results": 1
}

, output, 
{"type": "tool_reference", "tool_name": "TodoWrite"}
  • Inspect /app and seeded Lambda + role
  • Create DDB orders table
  • Create FIFO queues (main + dlq) with redrive
  • Fix consumer Lambda role policies
  • Fix consumer Lambda handler (batch failure shape + idempotency)
  • Create event source mapping main queue -> Lambda
  • Create apigw->sqs IAM role
  • Create REST API + resource + method + integration + deployment
  • End-to-end smoke test (POST, dedup, ordering, no DLQ)

Inspect /app and setup.sh

shell
ls /app && cat /app/setup.sh 2>/dev/null | head -200
output
setup.sh
starter
#!/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"

[stdout]
setup.sh
starter
#!/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"

Inspect starter dir and localstack health

shell
ls /app/starter 2>/dev/null && echo "---" && curl -sf http://localstack:4566/_localstack/health | head -50
output
setup.sh
---
{"services": {"acm": "disabled", "apigateway": "available", "cloudformation": "disabled", "cloudwatch": "disabled", "config": "disabled", "dynamodb": "available", "dynamodbstreams": "available", "ec2": "disabled", "es": "disabled", "events": "disabled", "firehose": "disabled", "iam": "running", "kinesis": "available", "kms": "disabled", "lambda": "running", "logs": "available", "opensearch": "disabled", "redshift": "disabled", "resource-groups": "disabled", "resourcegroupstaggingapi": "disabled", "route53": "disabled", "route53resolver": "disabled", "s3": "running", "s3control": "disabled", "scheduler": "disabled", "secretsmanager": "disabled", "ses": "disabled", "sns": "disabled", "sqs": "available", "ssm": "disabled", "stepfunctions": "disabled", "sts": "running", "support": "disabled", "swf": "disabled", "transcribe": "disabled"}, "edition": "community", "version": "4.13.1"}

[stdout]
setup.sh
---
{"services": {"acm": "disabled", "apigateway": "available", "cloudformation": "disabled", "cloudwatch": "disabled", "config": "disabled", "dynamodb": "available", "dynamodbstreams": "available", "ec2": "disabled", "es": "disabled", "events": "disabled", "firehose": "disabled", "iam": "running", "kinesis": "available", "kms": "disabled", "lambda": "running", "logs": "available", "opensearch": "disabled", "redshift": "disabled", "resource-groups": "disabled", "resourcegroupstaggingapi": "disabled", "route53": "disabled", "route53resolver": "disabled", "s3": "running", "s3control": "disabled", "scheduler": "disabled", "secretsmanager": "disabled", "ses": "disabled", "sns": "disabled", "sqs": "available", "ssm": "disabled", "stepfunctions": "disabled", "sts": "running", "support": "disabled", "swf": "disabled", "transcribe": "disabled"}, "edition": "community", "version": "4.13.1"}

Verify seeded Lambda and role exist

shell
aws --endpoint-url=http://localstack:4566 lambda get-function --function-name orders-consumer --query 'Configuration.[FunctionName,Role,Handler,Runtime,State]' --output json && echo "---" && aws --endpoint-url=http://localstack:4566 iam list-attached-role-policies --role-name orders-consumer-role
output
[
    "orders-consumer",
    "arn:aws:iam::000000000000:role/orders-consumer-role",
    "handler.lambda_handler",
    "python3.11",
    "Active"
]
---
{
    "AttachedPolicies": [
        {
            "PolicyName": "AWSLambdaBasicExecutionRole",
            "PolicyArn": "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
        }
    ]
}

[stdout]
[
    "orders-consumer",
    "arn:aws:iam::000000000000:role/orders-consumer-role",
    "handler.lambda_handler",
    "python3.11",
    "Active"
]
---
{
    "AttachedPolicies": [
        {
            "PolicyName": "AWSLambdaBasicExecutionRole",
            "PolicyArn": "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
        }
    ]
}

Check AWS env vars

shell
env | grep -E 'AWS|ENDPOINT' | sort
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

[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
I'll build this step by step. Starting with DDB and the queues.

Create orders DDB 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 \
  --query 'TableDescription.TableName' --output text
aws dynamodb wait table-exists --table-name orders
echo "ddb-ok"
output
orders
ddb-ok

[stdout]
orders
ddb-ok

Create FIFO queues with redrive

shell
set -e
DLQ_URL=$(aws sqs create-queue \
  --queue-name orders-dlq.fifo \
  --attributes FifoQueue=true,ContentBasedDeduplication=false \
  --query 'QueueUrl' --output text)
echo "DLQ_URL=$DLQ_URL"

DLQ_ARN=$(aws sqs get-queue-attributes --queue-url "$DLQ_URL" --attribute-names QueueArn --query 'Attributes.QueueArn' --output text)
echo "DLQ_ARN=$DLQ_ARN"

cat > /tmp/main_attrs.json <<JSON
{
  "FifoQueue": "true",
  "ContentBasedDeduplication": "false",
  "VisibilityTimeout": "60",
  "RedrivePolicy": "{\"deadLetterTargetArn\":\"$DLQ_ARN\",\"maxReceiveCount\":\"3\"}"
}
JSON
cat /tmp/main_attrs.json

MAIN_URL=$(aws sqs create-queue \
  --queue-name orders.fifo \
  --attributes file:///tmp/main_attrs.json \
  --query 'QueueUrl' --output text)
echo "MAIN_URL=$MAIN_URL"

MAIN_ARN=$(aws sqs get-queue-attributes --queue-url "$MAIN_URL" --attribute-names QueueArn --query 'Attributes.QueueArn' --output text)
echo "MAIN_ARN=$MAIN_ARN"

aws sqs get-queue-attributes --queue-url "$MAIN_URL" --attribute-names All --query 'Attributes.RedrivePolicy' --output text
output
DLQ_URL=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
{
  "FifoQueue": "true",
  "ContentBasedDeduplication": "false",
  "VisibilityTimeout": "60",
  "RedrivePolicy": "{\"deadLetterTargetArn\":\"arn:aws:sqs:us-east-1:000000000000:orders-dlq.fifo\",\"maxReceiveCount\":\"3\"}"
}
MAIN_URL=http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders.fifo
MAIN_ARN=arn:aws:sqs:us-east-1:000000000000:orders.fifo
{"deadLetterTargetArn":"arn:aws:sqs:us-east-1:000000000000:orders-dlq.fifo","maxReceiveCount":"3"}

[stdout]
DLQ_URL=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
{
  "FifoQueue": "true",
  "ContentBasedDeduplication": "false",
  "VisibilityTimeout": "60",
  "RedrivePolicy": "{\"deadLetterTargetArn\":\"arn:aws:sqs:us-east-1:000000000000:orders-dlq.fifo\",\"maxReceiveCount\":\"3\"}"
}
MAIN_URL=http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders.fifo
MAIN_ARN=arn:aws:sqs:us-east-1:000000000000:orders.fifo
{"deadLetterTargetArn":"arn:aws:sqs:us-east-1:000000000000:orders-dlq.fifo","maxReceiveCount":"3"}
  • Inspect /app and seeded Lambda + role
  • Create DDB orders table
  • Create FIFO queues (main + dlq) with redrive
  • Fix consumer Lambda role policies
  • Fix consumer Lambda handler (batch failure shape + idempotency)
  • Create event source mapping main queue -> Lambda
  • Create apigw->sqs IAM role
  • Create REST API + resource + method + integration + deployment
  • End-to-end smoke test (POST, dedup, ordering, no DLQ)

Attach inline policy to consumer role

shell
cat > /tmp/consumer_inline.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:UpdateItem",
        "dynamodb:GetItem",
        "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_inline.json
echo "policy-attached"
aws iam list-role-policies --role-name orders-consumer-role
output
policy-attached
{
    "PolicyNames": [
        "orders-consumer-inline"
    ]
}

[stdout]
policy-attached
{
    "PolicyNames": [
        "orders-consumer-inline"
    ]
}
Now fix the Lambda handler , proper `batchItemFailures` shape and idempotent put.

Update Lambda code with fixed 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.get("Error", {}).get("Code") == "ConditionalCheckFailedException":
            return
        raise


def lambda_handler(event, context):
    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}")
            failures.append({"itemIdentifier": record["messageId"]})

    return {"batchItemFailures": failures}
PY
(cd /tmp/lambda && zip -q handler.zip handler.py)
ls -la /tmp/lambda
aws lambda update-function-code \
  --function-name orders-consumer \
  --zip-file fileb:///tmp/lambda/handler.zip \
  --query '[FunctionName,LastUpdateStatus]' --output json
for _ in $(seq 1 30); do
  S=$(aws lambda get-function --function-name orders-consumer --query 'Configuration.LastUpdateStatus' --output text)
  [ "$S" = "Successful" ] && break
  sleep 1
done
echo "lambda-updated:$S"
output
total 16
drwxr-xr-x 2 root root 4096 Apr 28 14:06 .
drwxrwxrwt 1 root root 4096 Apr 28 14:06 ..
-rw-r--r-- 1 root root 1372 Apr 28 14:06 handler.py
-rw-r--r-- 1 root root  815 Apr 28 14:06 handler.zip
[
    "orders-consumer",
    "InProgress"
]
lambda-updated:Successful

[stdout]
total 16
drwxr-xr-x 2 root root 4096 Apr 28 14:06 .
drwxrwxrwt 1 root root 4096 Apr 28 14:06 ..
-rw-r--r-- 1 root root 1372 Apr 28 14:06 handler.py
-rw-r--r-- 1 root root  815 Apr 28 14:06 handler.zip
[
    "orders-consumer",
    "InProgress"
]
lambda-updated:Successful

Create event source mapping main queue -> 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 \
  --query '[UUID,State,FunctionResponseTypes]' --output json
sleep 2
aws lambda list-event-source-mappings --function-name orders-consumer \
  --query 'EventSourceMappings[].[UUID,State,EventSourceArn,FunctionResponseTypes]' --output json
output
[
    "d2f2da6c-324c-478d-b1d6-6c6c48d74d3c",
    "Creating",
    [
        "ReportBatchItemFailures"
    ]
]
[
    [
        "d2f2da6c-324c-478d-b1d6-6c6c48d74d3c",
        "Enabled",
        "arn:aws:sqs:us-east-1:000000000000:orders.fifo",
        [
            "ReportBatchItemFailures"
        ]
    ]
]

[stdout]
[
    "d2f2da6c-324c-478d-b1d6-6c6c48d74d3c",
    "Creating",
    [
        "ReportBatchItemFailures"
    ]
]
[
    [
        "d2f2da6c-324c-478d-b1d6-6c6c48d74d3c",
        "Enabled",
        "arn:aws:sqs:us-east-1:000000000000:orders.fifo",
        [
            "ReportBatchItemFailures"
        ]
    ]
]
  • Inspect /app and seeded Lambda + role
  • Create DDB orders table
  • Create FIFO queues (main + dlq) with redrive
  • Fix consumer Lambda role policies
  • Fix consumer Lambda handler (batch failure shape + idempotency)
  • Create event source mapping main queue -> Lambda
  • Create apigw->sqs IAM role
  • Create REST API + resource + method + integration + deployment
  • End-to-end smoke test (POST, dedup, ordering, no DLQ)

Create apigw->sqs IAM role with inline 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_inline.json <<'JSON'
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": ["sqs:SendMessage", "sqs:GetQueueUrl"],
      "Resource": "arn:aws:sqs:us-east-1:000000000000:orders.fifo"
    }
  ]
}
JSON
aws iam put-role-policy \
  --role-name apigw-to-sqs-role \
  --policy-name apigw-to-sqs-inline \
  --policy-document file:///tmp/apigw_inline.json
echo "apigw-role-ok"
APIGW_ROLE_ARN=$(aws iam get-role --role-name apigw-to-sqs-role --query 'Role.Arn' --output text)
echo "APIGW_ROLE_ARN=$APIGW_ROLE_ARN"
output
arn:aws:iam::000000000000:role/apigw-to-sqs-role
apigw-role-ok
APIGW_ROLE_ARN=arn:aws:iam::000000000000:role/apigw-to-sqs-role

[stdout]
arn:aws:iam::000000000000:role/apigw-to-sqs-role
apigw-role-ok
APIGW_ROLE_ARN=arn:aws:iam::000000000000:role/apigw-to-sqs-role
Now build the REST API: api → resource `/orders` → POST → AWS SQS integration with VTL mapping → deploy `dev`.

Create REST API, resource, method, integration, deployment

shell
set -e
APIGW_ROLE_ARN="arn:aws:iam::000000000000:role/apigw-to-sqs-role"

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"

aws apigateway put-method \
  --rest-api-id "$API_ID" \
  --resource-id "$RES_ID" \
  --http-method POST \
  --authorization-type NONE \
  --query '[httpMethod,authorizationType]' --output json

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 'statusCode' --output text

# VTL template -> URL-encoded SQS SendMessage form
cat > /tmp/req_template.txt <<'VTL'
Action=SendMessage&MessageBody=$util.urlEncode($input.body)&MessageGroupId=$util.urlEncode($input.path('$.merchant_id'))&MessageDeduplicationId=$util.urlEncode($input.path('$.order_id'))
VTL

# Build request-templates JSON safely
python3 - <<'PY' > /tmp/req_templates.json
import json
with open('/tmp/req_template.txt') as f:
    body = f.read().rstrip('\n')
print(json.dumps({"application/json": body}))
PY
cat /tmp/req_templates.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 "$APIGW_ROLE_ARN" \
  --request-parameters '{"integration.request.header.Content-Type":"'"'"'application/x-www-form-urlencoded'"'"'"}' \
  --request-templates file:///tmp/req_templates.json \
  --passthrough-behavior NEVER \
  --query '[type,uri,credentials]' --output json

aws apigateway put-integration-response \
  --rest-api-id "$API_ID" \
  --resource-id "$RES_ID" \
  --http-method POST \
  --status-code 200 \
  --response-templates '{"application/json":"{\"ok\":true}"}' \
  --query 'statusCode' --output text

aws apigateway create-deployment \
  --rest-api-id "$API_ID" \
  --stage-name dev \
  --query '[id,createdDate]' --output json

echo "API_ID=$API_ID" > /tmp/api_id
cat /tmp/api_id
output
API_ID=lyf0mwqkws
ROOT_ID=vmgqtiuirp
RES_ID=vzpwxgykof
[
    "POST",
    "NONE"
]
200
{"application/json": "Action=SendMessage&MessageBody=$util.urlEncode($input.body)&MessageGroupId=$util.urlEncode($input.path('$.merchant_id'))&MessageDeduplicationId=$util.urlEncode($input.path('$.order_id'))"}
[
    "AWS",
    "arn:aws:apigateway:us-east-1:sqs:path/000000000000/orders.fifo",
    "arn:aws:iam::000000000000:role/apigw-to-sqs-role"
]
200
[
    "kxo71cai3c",
    "2026-04-28T14:07:34+00:00"
]
API_ID=lyf0mwqkws

[stdout]
API_ID=lyf0mwqkws
ROOT_ID=vmgqtiuirp
RES_ID=vzpwxgykof
[
    "POST",
    "NONE"
]
200
{"application/json": "Action=SendMessage&MessageBody=$util.urlEncode($input.body)&MessageGroupId=$util.urlEncode($input.path('$.merchant_id'))&MessageDeduplicationId=$util.urlEncode($input.path('$.order_id'))"}
[
    "AWS",
    "arn:aws:apigateway:us-east-1:sqs:path/000000000000/orders.fifo",
    "arn:aws:iam::000000000000:role/apigw-to-sqs-role"
]
200
[
    "kxo71cai3c",
    "2026-04-28T14:07:34+00:00"
]
API_ID=lyf0mwqkws
  • Inspect /app and seeded Lambda + role
  • Create DDB orders table
  • Create FIFO queues (main + dlq) with redrive
  • Fix consumer Lambda role policies
  • Fix consumer Lambda handler (batch failure shape + idempotency)
  • Create event source mapping main queue -> Lambda
  • Create apigw->sqs IAM role
  • Create REST API + resource + method + integration + deployment
  • End-to-end smoke test (POST, dedup, ordering, no DLQ)

Smoke test: single POST, verify DDB and DLQ

shell
API_ID=lyf0mwqkws
URL="http://localstack:4566/restapis/$API_ID/dev/_user_request_/orders"
echo "URL=$URL"

# Single POST
echo "--- POST 1 ---"
curl -sS -o /tmp/r1.json -w "HTTP=%{http_code}\n" -H 'Content-Type: application/json' \
  -X POST "$URL" \
  -d '{"order_id":"o-1","merchant_id":"m-1","amount":100}'
cat /tmp/r1.json; echo

sleep 5

echo "--- DDB scan ---"
aws dynamodb scan --table-name orders --output json

echo "--- DLQ depth ---"
aws sqs get-queue-attributes --queue-url http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders-dlq.fifo \
  --attribute-names ApproximateNumberOfMessages --query 'Attributes.ApproximateNumberOfMessages' --output text
output
URL=http://localstack:4566/restapis/lyf0mwqkws/dev/_user_request_/orders
--- POST 1 ---
HTTP=200
{"ok":true}
--- DDB scan ---
{
    "Items": [],
    "Count": 0,
    "ScannedCount": 0,
    "ConsumedCapacity": null
}
--- DLQ depth ---
0

[stdout]
URL=http://localstack:4566/restapis/lyf0mwqkws/dev/_user_request_/orders
--- POST 1 ---
HTTP=200
{"ok":true}
--- DDB scan ---
{
    "Items": [],
    "Count": 0,
    "ScannedCount": 0,
    "ConsumedCapacity": null
}
--- DLQ depth ---
0
HTTP 200 came back but DDB is empty. Let me check whether the message hit the main queue and what Lambda did.

Check main queue depth and Lambda logs

shell
echo "--- Main queue depth ---"
aws sqs get-queue-attributes \
  --queue-url http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders.fifo \
  --attribute-names ApproximateNumberOfMessages ApproximateNumberOfMessagesNotVisible

sleep 5
echo "--- Lambda log groups ---"
aws logs describe-log-groups --log-group-name-prefix /aws/lambda/orders-consumer --query 'logGroups[].logGroupName' --output text
echo "--- streams ---"
aws logs describe-log-streams --log-group-name /aws/lambda/orders-consumer --order-by LastEventTime --descending --max-items 3 --query 'logStreams[].logStreamName' --output text 2>&1 | head -20
output
--- Main queue depth ---
{
    "Attributes": {
        "ApproximateNumberOfMessages": "0",
        "ApproximateNumberOfMessagesNotVisible": "0"
    }
}
--- Lambda log groups ---
/aws/lambda/orders-consumer
--- streams ---
2026/04/28/[$LATEST]99718c6351bf64c886adc12de4433842

[stdout]
--- Main queue depth ---
{
    "Attributes": {
        "ApproximateNumberOfMessages": "0",
        "ApproximateNumberOfMessagesNotVisible": "0"
    }
}
--- Lambda log groups ---
/aws/lambda/orders-consumer
--- streams ---
2026/04/28/[$LATEST]99718c6351bf64c886adc12de4433842

Read latest Lambda log stream

shell
aws logs get-log-events \
  --log-group-name /aws/lambda/orders-consumer \
  --log-stream-name '2026/04/28/[$LATEST]99718c6351bf64c886adc12de4433842' \
  --limit 100 --query 'events[].message' --output text
output
START RequestId: 6358e3dd-a211-40af-b7da-5952712c659b Version: $LATEST
	END RequestId: 6358e3dd-a211-40af-b7da-5952712c659b
	REPORT RequestId: 6358e3dd-a211-40af-b7da-5952712c659b	Duration: 125.25 ms	Billed Duration: 126 ms	Memory Size: 512 MB	Max Memory Used: 512 MB

[stdout]
START RequestId: 6358e3dd-a211-40af-b7da-5952712c659b Version: $LATEST
	END RequestId: 6358e3dd-a211-40af-b7da-5952712c659b
	REPORT RequestId: 6358e3dd-a211-40af-b7da-5952712c659b	Duration: 125.25 ms	Billed Duration: 126 ms	Memory Size: 512 MB	Max Memory Used: 512 MB
Lambda fired with an empty event , message likely never landed. Let me check the integration response handling and try a direct SQS send to isolate the problem.

Direct SQS send to verify Lambda+ESM+DDB path

shell
echo "--- direct SQS send to FIFO ---"
aws sqs send-message \
  --queue-url http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders.fifo \
  --message-body '{"order_id":"o-direct","merchant_id":"m-direct","amount":50}' \
  --message-group-id m-direct \
  --message-deduplication-id o-direct \
  --query '[MessageId,SequenceNumber]' --output json
sleep 4
echo "--- DDB scan ---"
aws dynamodb scan --table-name orders --output json
echo "--- queues ---"
aws sqs get-queue-attributes --queue-url http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders.fifo --attribute-names ApproximateNumberOfMessages
aws sqs get-queue-attributes --queue-url http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders-dlq.fifo --attribute-names ApproximateNumberOfMessages
output
--- direct SQS send to FIFO ---
[
    "a2e6d139-f276-446d-a674-448eeac42ff2",
    "15267623239854063617"
]
--- DDB scan ---
{
    "Items": [
        {
            "created_at": {
                "N": "1777385282080"
            },
            "amount": {
                "N": "100"
            },
            "merchant_id": {
                "S": "m-1"
            },
            "order_id": {
                "S": "o-1"
            }
        }
    ],
    "Count": 1,
    "ScannedCount": 1,
    "ConsumedCapacity": null
}
--- queues ---
{
    "Attributes": {
        "ApproximateNumberOfMessages": "1"
    }
}
{
    "Attributes": {
        "ApproximateNumberOfMessages": "0"
    }
}

[stdout]
--- direct SQS send to FIFO ---
[
    "a2e6d139-f276-446d-a674-448eeac42ff2",
    "15267623239854063617"
]
--- DDB scan ---
{
    "Items": [
        {
            "created_at": {
                "N": "1777385282080"
            },
            "amount": {
                "N": "100"
            },
            "merchant_id": {
                "S": "m-1"
            },
            "order_id": {
                "S": "o-1"
            }
        }
    ],
    "Count": 1,
    "ScannedCount": 1,
    "ConsumedCapacity": null
}
--- queues ---
{
    "Attributes": {
        "ApproximateNumberOfMessages": "1"
    }
}
{
    "Attributes": {
        "ApproximateNumberOfMessages": "0"
    }
}
Both POSTs landed , `o-1` from the API call is in DDB. Earlier Lambda invocation just looked empty in the first log stream. Let me wait for the direct send to also process and run the full verification suite.

Re-check after wait

shell
sleep 6
echo "--- DDB scan ---"
aws dynamodb scan --table-name orders --output json
echo "--- main queue ---"
aws sqs get-queue-attributes --queue-url http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders.fifo --attribute-names ApproximateNumberOfMessages --query 'Attributes' --output json
echo "--- dlq ---"
aws sqs get-queue-attributes --queue-url http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders-dlq.fifo --attribute-names ApproximateNumberOfMessages --query 'Attributes' --output json
output
--- DDB scan ---
{
    "Items": [
        {
            "created_at": {
                "N": "1777385318337"
            },
            "amount": {
                "N": "50"
            },
            "merchant_id": {
                "S": "m-direct"
            },
            "order_id": {
                "S": "o-direct"
            }
        },
        {
            "created_at": {
                "N": "1777385282080"
            },
            "amount": {
                "N": "100"
            },
            "merchant_id": {
                "S": "m-1"
            },
            "order_id": {
                "S": "o-1"
            }
        }
    ],
    "Count": 2,
    "ScannedCount": 2,
    "ConsumedCapacity": null
}
--- main queue ---
{
    "ApproximateNumberOfMessages": "0"
}
--- dlq ---
{
    "ApproximateNumberOfMessages": "0"
}

[stdout]
--- DDB scan ---
{
    "Items": [
        {
            "created_at": {
                "N": "1777385318337"
            },
            "amount": {
                "N": "50"
            },
            "merchant_id": {
                "S": "m-direct"
            },
            "order_id": {
                "S": "o-direct"
            }
        },
        {
            "created_at": {
                "N": "1777385282080"
            },
            "amount": {
                "N": "100"
            },
            "merchant_id": {
                "S": "m-1"
            },
            "order_id": {
                "S": "o-1"
            }
        }
    ],
    "Count": 2,
    "ScannedCount": 2,
    "ConsumedCapacity": null
}
--- main queue ---
{
    "ApproximateNumberOfMessages": "0"
}
--- dlq ---
{
    "ApproximateNumberOfMessages": "0"
}
Both rows landed; queues drained. Now full verifier-style test: dedup on re-POST, ordering across two order_ids, no DLQ.

Full verifier test: ordering, dedup, no DLQ

shell
set -e
# Clean DDB so we test against a known empty start
aws dynamodb delete-item --table-name orders --key '{"order_id":{"S":"o-1"}}' >/dev/null
aws dynamodb delete-item --table-name orders --key '{"order_id":{"S":"o-direct"}}' >/dev/null
aws dynamodb scan --table-name orders --query 'Count' --output text

API_ID=lyf0mwqkws
URL="http://localstack:4566/restapis/$API_ID/dev/_user_request_/orders"

echo "--- POST order A ---"
curl -sS -o - -w "\nHTTP=%{http_code}\n" -H 'Content-Type: application/json' -X POST "$URL" \
  -d '{"order_id":"oA","merchant_id":"mZ","amount":111}'
sleep 1
echo "--- POST order B (same merchant) ---"
curl -sS -o - -w "\nHTTP=%{http_code}\n" -H 'Content-Type: application/json' -X POST "$URL" \
  -d '{"order_id":"oB","merchant_id":"mZ","amount":222}'

sleep 6
echo "--- DDB after first two POSTs ---"
aws dynamodb scan --table-name orders --output json

echo "--- Re-POST order A (dedup test) ---"
curl -sS -o - -w "\nHTTP=%{http_code}\n" -H 'Content-Type: application/json' -X POST "$URL" \
  -d '{"order_id":"oA","merchant_id":"mZ","amount":999}'

# Wait past SQS dedup window... can't actually wait 5 min, but the conditional put on DDB will catch it
sleep 6
echo "--- DDB after re-POST ---"
aws dynamodb scan --table-name orders --output json

echo "--- queues ---"
aws sqs get-queue-attributes --queue-url http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders.fifo --attribute-names ApproximateNumberOfMessages ApproximateNumberOfMessagesNotVisible --query 'Attributes' --output json
aws sqs get-queue-attributes --queue-url http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/orders-dlq.fifo --attribute-names ApproximateNumberOfMessages --query 'Attributes' --output json
output
0
--- POST order A ---
{"ok":true}
HTTP=200
--- POST order B (same merchant) ---
{"ok":true}
HTTP=200
--- DDB after first two POSTs ---
{
    "Items": [
        {
            "created_at": {
                "N": "1777385345781"
            },
            "amount": {
                "N": "222"
            },
            "merchant_id": {
                "S": "mZ"
            },
            "order_id": {
                "S": "oB"
            }
        },
        {
            "created_at": {
                "N": "1777385345728"
            },
            "amount": {
                "N": "111"
            },
            "merchant_id": {
                "S": "mZ"
            },
            "order_id": {
                "S": "oA"
            }
        }
    ],
    "Count": 2,
    "ScannedCount": 2,
    "ConsumedCapacity": null
}
--- Re-POST order A (dedup test) ---
{"ok":true}
HTTP=200
--- DDB after re-POST ---
{
    "Items": [
        {
            "created_at": {
                "N": "1777385345781"
            },
            "amount": {
                "N": "222"
            },
            "merchant_id": {
                "S": "mZ"
            },
            "order_id": {
                "S": "oB"
            }
        },
        {
            "created_at": {
                "N": "1777385345728"
            },
            "amount": {
                "N": "111"
            },
            "merchant_id": {
                "S": "mZ"
            },
            "order_id": {
                "S": "oA"
            }
        }
    ],
    "Count": 2,
    "ScannedCount": 2,
    "ConsumedCapacity": null
}
--- queues ---
{
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "0"
}
{
    "ApproximateNumberOfMessages": "0"
}

[stdout]
0
--- POST order A ---
{"ok":true}
HTTP=200
--- POST order B (same merchant) ---
{"ok":true}
HTTP=200
--- DDB after first two POSTs ---
{
    "Items": [
        {
            "created_at": {
                "N": "1777385345781"
            },
            "amount": {
                "N": "222"
            },
            "merchant_id": {
                "S": "mZ"
            },
            "order_id": {
                "S": "oB"
            }
        },
        {
            "created_at": {
                "N": "1777385345728"
            },
            "amount": {
                "N": "111"
            },
            "merchant_id": {
                "S": "mZ"
            },
            "order_id": {
                "S": "oA"
            }
        }
    ],
    "Count": 2,
    "ScannedCount": 2,
    "ConsumedCapacity": null
}
--- Re-POST order A (dedup test) ---
{"ok":true}
HTTP=200
--- DDB after re-POST ---
{
    "Items": [
        {
            "created_at": {
                "N": "1777385345781"
            },
            "amount": {
                "N": "222"
            },
            "merchant_id": {
                "S": "mZ"
            },
            "order_id": {
                "S": "oB"
            }
        },
        {
            "created_at": {
                "N": "1777385345728"
            },
            "amount": {
                "N": "111"
            },
            "merchant_id": {
                "S": "mZ"
            },
            "order_id": {
                "S": "oA"
            }
        }
    ],
    "Count": 2,
    "ScannedCount": 2,
    "ConsumedCapacity": null
}
--- queues ---
{
    "ApproximateNumberOfMessages": "0",
    "ApproximateNumberOfMessagesNotVisible": "0"
}
{
    "ApproximateNumberOfMessages": "0"
}
  • Inspect /app and seeded Lambda + role
  • Create DDB orders table
  • Create FIFO queues (main + dlq) with redrive
  • Fix consumer Lambda role policies
  • Fix consumer Lambda handler (batch failure shape + idempotency)
  • Create event source mapping main queue -> Lambda
  • Create apigw->sqs IAM role
  • Create REST API + resource + method + integration + deployment
  • End-to-end smoke test (POST, dedup, ordering, no DLQ)
All checks pass: - POST order A then order B (same merchant) → both 200, both stored with `oA.created_at < oB.created_at` (post order preserved). - Re-POST `oA` with `amount:999` → 200 returned, but DDB row unchanged (`amount` still 111). The conditional `attribute_not_exists(order_id)` PutItem catches duplicates as no-ops; SQS dedup handles same-window retries too. - Main queue and DLQ both at 0. What was built: - DDB `orders`, pk `order_id` String. - `orders-dlq.fifo` then `orders.fifo` with `RedrivePolicy {maxReceiveCount:3}`. - `orders-consumer-role` got an inline policy adding `dynamodb:PutItem`/`UpdateItem`/`GetItem`/`DescribeTable` on the table and `sqs:ReceiveMessage`/`DeleteMessage`/`GetQueueAttributes`/`ChangeMessageVisibility` on the main queue. - `orders-consumer` handler rewritten: returns `{"batchItemFailures":[...]}`, idempotent via conditional PutItem; `ConditionalCheckFailedException` is treated as success. - Event-source mapping `orders.fifo → orders-consumer` with `FunctionResponseTypes=[ReportBatchItemFailures]`. - `apigw-to-sqs-role` (apigateway trust) → inline `sqs:SendMessage` on `orders.fifo`. - REST API `orders-api` → resource `/orders` → POST → AWS service integration to `arn:aws:apigateway:us-east-1:sqs:path/000000000000/orders.fifo` with `Content-Type: application/x-www-form-urlencoded` and the VTL template `Action=SendMessage&MessageBody=…&MessageGroupId=$merchant_id&MessageDeduplicationId=$order_id`. Method response 200, integration response 200 → `{"ok":true}`. Deployed 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/H6x3x3aglbhh7KMNv8ac1/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 0xffff7d1f55b0>

    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': 'kxo71cai3c', 'createdDate': datetime.datetime(2026, 4, 28, 14, 7, 34, tzinfo=tzlocal())}]
E       assert 1 >= 2
E        +  where 1 = len([{'createdDate': datetime.datetime(2026, 4, 28, 14, 7, 34, tzinfo=tzlocal()), 'id': 'kxo71cai3c'}])

/tests/test_outputs.py:350: AssertionError
=============================== warnings summary ===============================
test_outputs.py: 69 warnings
  /root/.cache/uv/archive-v0/H6x3x3aglbhh7KMNv8ac1/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, 69 warnings in 33.48s ==================

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_aa21c7fe74da44e9. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_aa21c7fe74da44e9 · verifier authoritative; classifier explanatory.