Step Functions Agent Skill

AWS Step Functions workflow orchestration with state machines. Use when designing workflows, implementing error handling, configuring parallel execution, integrating with AWS services, or debugging executions.

5k tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

1139

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/itsmostafa/aws-agent-skills --skill step-functions

The instruction itself

28 sections, as written by the author

AWS Step Functions

AWS Step Functions is a serverless orchestration service that lets you build and run workflows using state machines. Coordinate multiple AWS services into business-critical applications.

Core Concepts
Common Patterns
CLI Reference
Best Practices
Troubleshooting
References

Core Concepts

Workflow Types

| Type | Description | Pricing |

|------|-------------|---------|

| Standard | Long-running, durable, exactly-once | Per state transition |

| Express | High-volume, short-duration | Per execution (time + memory) |

State Types

| State | Description |

|-------|-------------|

| Task | Execute work (Lambda, API call) |

| Choice | Conditional branching |

| Parallel | Execute branches concurrently |

| Map | Iterate over array |

| Wait | Delay execution |

| Pass | Pass input to output |

| Succeed | End successfully |

| Fail | End with failure |

Amazon States Language (ASL)

JSON-based language for defining state machines.

Common Patterns

Simple Lambda Workflow

{
  "Comment": "Process order workflow",
  "StartAt": "ValidateOrder",
  "States": {
    "ValidateOrder": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:123456789012:function:ValidateOrder",
      "Next": "ProcessPayment"
    },
    "ProcessPayment": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:123456789012:function:ProcessPayment",
      "Next": "FulfillOrder"
    },
    "FulfillOrder": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:us-east-1:123456789012:function:FulfillOrder",
      "End": true
    }
  }
}

Create State Machine

AWS CLI:

aws stepfunctions create-state-machine \
  --name OrderWorkflow \
  --definition file://workflow.json \
  --role-arn arn:aws:iam::123456789012:role/StepFunctionsRole \
  --type STANDARD

boto3:

import boto3
import json

sfn = boto3.client('stepfunctions')

definition = {
    "Comment": "Order workflow",
    "StartAt": "ProcessOrder",
    "States": {
        "ProcessOrder": {
            "Type": "Task",
            "Resource": "arn:aws:lambda:...",
            "End": True
        }
    }
}

response = sfn.create_state_machine(
    name='OrderWorkflow',
    definition=json.dumps(definition),
    roleArn='arn:aws:iam::123456789012:role/StepFunctionsRole',
    type='STANDARD'
)

Start Execution

import boto3
import json

sfn = boto3.client('stepfunctions')

response = sfn.start_execution(
    stateMachineArn='arn:aws:states:us-east-1:123456789012:stateMachine:OrderWorkflow',
    name='order-12345',
    input=json.dumps({
        'order_id': '12345',
        'customer_id': 'cust-789',
        'items': [{'product_id': 'prod-1', 'quantity': 2}]
    })
)

execution_arn = response['executionArn']

Choice State (Conditional Logic)

{
  "StartAt": "CheckOrderValue",
  "States": {
    "CheckOrderValue": {
      "Type": "Choice",
      "Choices": [
        {
          "Variable": "$.total",
          "NumericGreaterThan": 1000,
          "Next": "HighValueOrder"
        },
        {
          "Variable": "$.priority",
          "StringEquals": "rush",
          "Next": "RushOrder"
        }
      ],
      "Default": "StandardOrder"
    },
    "HighValueOrder": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:...:function:ProcessHighValue",
      "End": true
    },
    "RushOrder": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:...:function:ProcessRush",
      "End": true
    },
    "StandardOrder": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:...:function:ProcessStandard",
      "End": true
    }
  }
}

Parallel Execution

{
  "StartAt": "ProcessInParallel",
  "States": {
    "ProcessInParallel": {
      "Type": "Parallel",
      "Branches": [
        {
          "StartAt": "UpdateInventory",
          "States": {
            "UpdateInventory": {
              "Type": "Task",
              "Resource": "arn:aws:lambda:...:function:UpdateInventory",
              "End": true
            }
          }
        },
        {
          "StartAt": "SendNotification",
          "States": {
            "SendNotification": {
              "Type": "Task",
              "Resource": "arn:aws:lambda:...:function:SendNotification",
              "End": true
            }
          }
        },
        {
          "StartAt": "UpdateAnalytics",
          "States": {
            "UpdateAnalytics": {
              "Type": "Task",
              "Resource": "arn:aws:lambda:...:function:UpdateAnalytics",
              "End": true
            }
          }
        }
      ],
      "Next": "Complete"
    },
    "Complete": {
      "Type": "Succeed"
    }
  }
}

Map State (Iteration)

{
  "StartAt": "ProcessItems",
  "States": {
    "ProcessItems": {
      "Type": "Map",
      "ItemsPath": "$.items",
      "MaxConcurrency": 10,
      "Iterator": {
        "StartAt": "ProcessItem",
        "States": {
          "ProcessItem": {
            "Type": "Task",
            "Resource": "arn:aws:lambda:...:function:ProcessItem",
            "End": true
          }
        }
      },
      "ResultPath": "$.processedItems",
      "End": true
    }
  }
}

Error Handling

{
  "StartAt": "ProcessWithRetry",
  "States": {
    "ProcessWithRetry": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:...:function:Process",
      "Retry": [
        {
          "ErrorEquals": ["Lambda.ServiceException", "Lambda.TooManyRequestsException"],
          "IntervalSeconds": 2,
          "MaxAttempts": 6,
          "BackoffRate": 2
        },
        {
          "ErrorEquals": ["States.Timeout"],
          "IntervalSeconds": 5,
          "MaxAttempts": 3,
          "BackoffRate": 1.5
        }
      ],
      "Catch": [
        {
          "ErrorEquals": ["CustomError"],
          "ResultPath": "$.error",
          "Next": "HandleCustomError"
        },
        {
          "ErrorEquals": ["States.ALL"],
          "ResultPath": "$.error",
          "Next": "HandleAllErrors"
        }
      ],
      "End": true
    },
    "HandleCustomError": {
      "Type": "Task",
      "Resource": "arn:aws:lambda:...:function:HandleCustom",
      "End": true
    },
    "HandleAllErrors": {
      "Type": "Fail",
      "Error": "ProcessingFailed",
      "Cause": "An error occurred during processing"
    }
  }
}

CLI Reference

State Machine Management

| Command | Description |

|---------|-------------|

| aws stepfunctions create-state-machine | Create state machine |

| aws stepfunctions update-state-machine | Update definition |

| aws stepfunctions delete-state-machine | Delete state machine |

| aws stepfunctions list-state-machines | List state machines |

| aws stepfunctions describe-state-machine | Get details |

Executions

| Command | Description |

|---------|-------------|

| aws stepfunctions start-execution | Start execution |

| aws stepfunctions stop-execution | Stop execution |

| aws stepfunctions describe-execution | Get execution details |

| aws stepfunctions list-executions | List executions |

| aws stepfunctions get-execution-history | Get execution history |

Best Practices

Design

Keep states focused — one purpose per state
Use meaningful state names
Implement comprehensive error handling
Use Parallel for independent tasks
Use Map for batch processing

Performance

Use Express workflows for high-volume, short tasks
Set appropriate timeouts
Limit Map concurrency to avoid throttling
Use SDK integrations when possible (avoid Lambda wrapper)

Reliability

Retry transient errors
Catch and handle specific errors
Use idempotent operations
Enable X-Ray tracing

Cost Optimization

Use Express for short workflows (< 5 minutes)
Combine related operations to reduce transitions
Use Wait states instead of Lambda delays

Troubleshooting

Execution Failed

# Get execution history
aws stepfunctions get-execution-history \
  --execution-arn arn:aws:states:us-east-1:123456789012:execution:MyWorkflow:exec-123 \
  --query 'events[?type==`TaskFailed` || type==`ExecutionFailed`]'

Lambda Timeout

Causes:

Lambda running too long
Task timeout too short

Fix:

{
  "Type": "Task",
  "Resource": "arn:aws:lambda:...",
  "TimeoutSeconds": 300,
  "HeartbeatSeconds": 60
}

State Stuck

Check:

Task state waiting for callback
Wait state not yet elapsed
Activity worker not responding

Invalid State Machine

# Validate definition
aws stepfunctions validate-state-machine-definition \
  --definition file://workflow.json

References

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How to use it

Copy the folder

Take itsmostafa/step-functions from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.

Step Functions Agent Skill

Install

The instruction itself

AWS Step Functions

Table of Contents

Core Concepts

Workflow Types

State Types

Amazon States Language (ASL)

Common Patterns

Simple Lambda Workflow

Create State Machine

Start Execution

Choice State (Conditional Logic)

Parallel Execution

Map State (Iteration)

Error Handling

CLI Reference

State Machine Management

Executions

Best Practices

Design

Performance

Reliability

Cost Optimization

Troubleshooting

Execution Failed

Lambda Timeout

State Stuck

Invalid State Machine

References

Other skills for the same job

How to use it