Reverse Engineering Your Software program Structure with Claude Code to Assist Claude Code – O’Reilly

I’ve been utilizing Claude Code for quite a lot of functions, and one factor I’ve realized is that the extra it understands concerning the performance of the system (the area, the use circumstances, the end-to-end flows), the extra it might probably assist me.

For instance, after I paste a manufacturing error log, Claude can learn the stack hint, determine the affected code, and inform me if there’s a bug. However when the difficulty is extra complicated, like a buyer help ticket, and there’s no stack hint, Claude is much less helpful.

The principle problem is that end-to-end processes are lengthy and sophisticated, spanning many code repositories. So simply asking Claude Code to investigate a single repository wasn’t going to work (and the default /init wasn’t producing ample element even for this single codebase).

So I made a decision to make use of Claude Code to investigate the system to map out the end-to-end flows related to the area I work in in order that Claude Code (and people) can use this to deal with extra complicated challenges.

This submit shares what I knocked collectively in someday, constructing on data and tooling I’ve already gained from actual work examples and experiments.

That is one submit in a sequence. You will discover the opposite posts right here.

This submit was written 100% by me. I requested Claude to generate the anonymized instance on the finish mirroring the kind of content material and elegance utilized in the true examples I created.

Setting the Preliminary Context

To start my mission, I created a really mild necessities doc:

# AI Structure Evaluation

This doc accommodates the directions for an necessary activity - utilizing AI to outline the structure of this technique, in order that it may be utilized by people and AI brokers to extra simply perceive the system.

## Goal

Map out the entire flows that this utility is concerned in (use sub brokers the place essential to work in parallel). A stream ought to map out the end-to-process from an motion within the UI (within the [readacted] repo) to a BFF, to backend APIs, or flows which are triggered by occasions.

Flows ought to be documented in Mermaid format to permit AI brokers to grasp, for versioning (in git), and for straightforward visualization.

## Necessities

Every stream ought to have a descriptive title and will embody:

1. The URL path of the web page the place the interplay is triggered
2. The URL path of the BFF endpoint (and the repository it lives in)
3. The URL path of calls made to downstream providers
4. Any database interactions
5. Any occasions produced or consumed (full title of occasion e.g. orders.orderPlaced)
6. Shoppers of occasions (if straightforward to determine)
7. Any workflows triggered (just like the synchronizeOrder)

To do that, you will want to look in different repositories, which might be discovered within the dad or mum folder. The GitHub shopper can be used if needed.

The record of flows ought to stay in ../flows/index.md and every particular person stream ought to be outlined in a separate folder.

# The place to search out data

- /docs/structure accommodates varied folders describing the design of this technique and area data
- Every API mission on this repository ([redacted], [redacted]) has an openapi.json. This should be used to determine all flows and validate. The [redacted] and [redacted] repositories even have openapi spec information
- The entities within the area [redacted], [redacted] [redacted] have technique that clearly describe the area operations that may be carried out on them. Equally, every operation is invoke from a use case that clearly describes the use case

The output I need is end-to-end flows like:
UI -> BFF -> API -> replace DB -> publish occasion -> handler -> use case -> publish occasion -> …

I don’t need 10 completely different sorts of structure diagrams and completely different ranges of element. I need Claude Code to grasp the habits of the system so it might probably determine anomalies (by manufacturing information and logs) and analyze the impression of potential modifications.

I additionally created some mild details about the system in these two information:

The area ideas file explains the entities within the system. Very transient clarification. The system overview file explains the connection between this codebase and different repositories, which is essential. Once more, it’s very mild—a bullet record of repository names and one or two sentences describing their relationship to this one.

Looking out throughout a number of repositories

The directions for this activity stay inside the primary repository of the area I work in. That is the middle of the universe for this agent, however it wants to have the ability to learn different repositories to hitch up the end-to-end stream.

The answer I exploit for that is within the description above:

To do that, you will want to look in different repositories which might be discovered within the dad or mum folder. The GitHub shopper can be used if needed.

I give Claude the next permissions in .claude/settings.native.json and it might probably then entry all of the repositories on machine or use the GitHub shopper if it thinks there are repositories I don’t have obtainable regionally:

"permissions": {
   "permit": [
     ...
     "Read(//Users/nicktune/code/**)",
     ...

Telling Claude where to look

You’ll notice the requirements also give Claude tips on where to look for key information like Open API spec files, which are like an index of the operations the application supports.

This is useful as a validation mechanism later in the flow. I would ask Claude, “List all of the API endpoints and events produced or consumed by this application—are there any that aren’t part of any flows.” I can then see if we may have missed anything important.

Mapping the First Flow

I put Claude in plan mode and asked it to read the file. It then popped up a short questionnaire asking me about my needs and preferences. One of the questions it asked was process related: Should we map out the whole system in parallel, work step-by-step, etc.?

I said, let’s do the first one together and use this as a template for the others to follow.

It took about two hours to build the first flow as I reviewed what Claude produced and gave feedback on what I needed. For example, at first it created a sequence diagram which looked nice but was too hard to read for complex flows that involve many repositories.

Eventually, we settled on horizontal flow diagrams where each repository is a container and we defined what steps could be. At first, it went too granular with the steps adding individual method calls.

### diagram.mermaid Requirements
**CRITICAL RULES:**
1. **File Format**: Must be pure Mermaid syntax with `.mermaid` extension- NO markdown headers
 - NO markdown code fences (no ` ```mermaid ` wrapper)
 - Starts directly with `flowchart LR`
2. **Use Swimlane Format**: `flowchart LR` (left-to-right with horizontal swimlanes)
 - Each repository is a horizontal swimlane (subgraph)
 - Flow progresses left to right
 - Swimlane labels should be prominent (use emoji for visibility)
 - Example: `subgraph systemA["🔧 systemA"]`
3. **Methods as Containers**:
 - Every repository MUST be a `subgraph` (horizontal swimlane)
 - Repository title is the subgraph label
 - Operations are nodes contained in the subgraph
 - Use `path LR` inside every subgraph
4. **Legitimate Step Varieties** - A step within the diagram can ONLY be one of many following:
 - **HTTP Endpoint**: Full endpoint path (e.g., `POST /blah/{blahId}/subblah`)
 - **Mixture Methodology Name**: Area technique on an mixture (e.g., `Order.place`, `Transport.organiz`)
 - **Database Operation**: Proven with cylinder form `[(Database: INSERT order)]`
 - **Occasion Publication**: (e.g., `Publish: personal.ordering.order.positioned`)
 - **Workflow Set off**: Should be labeled as workflow (e.g., `⚙️ Workflow: syncOrders`)
 - **Workflow Step**: Any step inside a workflow MUST embody the workflow title as prefix (e.g., `syncOrderWorkflow: Replace legacy order`, `updateOrderInfo: POST /legacy/fill-order`)
 - **Lambda Invocation**: (e.g., `Lambda: blah-blah-lambda-blah-blah`)
 - **UI Actions**: Person interactions (e.g., `Present modal kind`, `Person enters firstName, lastName`)

I’ve added an anonymized stream on the finish of this doc.

I additionally had so as to add some corrections to Claude to make sure it was wanting in all the proper locations and understanding what sure ideas imply in different components of our system; we weren’t simply iterating on the diagram for 2 hours.

Selecting the Subsequent Move

After the primary stream, the subsequent flows went a lot sooner. I verified the output of every stream and gave Claude suggestions, however usually round quarter-hour, and more often than not it was working so I may do different issues whereas ready.

One of many fascinating challenges was deciding which flows are literally wanted? What’s a stream? The place ought to a stream begin and finish? What about relationships between flows?

Right here I used to be within the driving seat fairly a bit. I requested Claude to suggest flows (simply record them earlier than analyzing) after which I requested it to indicate me how every API endpoint and occasion match into the flows, and we used that to iterate a bit.

One of many issues I needed to do after Claude had produced the primary draft is to ask, “Are you certain there are not any different customers for these occasions that aren’t listed right here?” It could then do a extra thorough search and generally discover customers in repositories I didn’t have regionally. (It could use GitHub search.)

Studying worth

As I reviewed every use case, I used to be studying issues concerning the system that I didn’t totally perceive or possibly there have been nuances I wasn’t conscious of. This alone would have justified all the trouble I spent on this.

Then I began to think about the worth for people who find themselves new to a codebase or a legacy system that no person understands anymore. Or possibly somebody who works in a unique group and wishes to determine how a bug or a change of their area is expounded to different domains.

Evolving the Necessities

As we went by the method, I repeatedly instructed Claude to replace the necessities file. So after we’d completed the primary stream we had directions like this added to the file:

## Documentation Construction

Every stream should be documented in a separate folder with the next construction:

```
docs/structure/flows/[flow-name]/
├── README.md              # Full documentation (all content material in a single file)
└── diagram.mermaid        # Mermaid diagram
```

**IMPORTANT**: Use ONLY these two information. Do NOT create separate diagram-notes.md or different information. Preserve all documentation consolidated in README.md for simpler upkeep.

### README.md Contents

**Use the blueprint as a template**: `docs/structure/flows/[redacted]/`

The file is now 449 strains lengthy.

One of many causes I did this was in order that I may begin a brand new Claude session, now or sooner or later, with no utterly clear context window and execute the method to get related outcomes.

I did truly use a brand new session to map every new stream to validate that the necessities had been considerably repeatable. Typically they had been, however usually Claude would ignore some components of the necessities. So on the finish, I instructed it to evaluate the necessities and evaluate the outputs, and it will normally determine many of the errors it had made and repair them.

Right here’s an instance of among the guidelines that began to construct up. Some had been to make sure Claude produced the proper kind of output, and a few had been to assist Claude keep away from widespread errors like Mermaid syntax errors.

### 2. Hint Workflows to Their Remaining Occasion
**Drawback**: Lacking occasions since you do not learn the precise workflow implementation.
**Rule**: Once you encounter a workflow, you MUST:
1. Discover the workflow definition file (normally `.asl.json` for AWS Step Features)
2. Learn the ENTIRE workflow to see ALL occasions it publishes
3. Doc EVERY occasion in sequence
**Instance from our blueprint**:
- We initially thought `[readacted]` ended with `[readacted]`
- Studying `[redacted].asl.json` revealed it truly ends with `[readacted]`
- This occasion was CRITICAL to the stream persevering with
**File areas**:
- Integrations workflows: `[another-repo]/domains/*/workflows/*.asl.json`
- Search for `SendEvent` or `publish` actions within the workflow steps

Claude Code by no means follows each instruction as described. However including these guidelines does appear to extend the standard and scale back the variety of iterations wanted.

Testing the Output

After I mapped out 4 or 5 of the flows, I made a decision it was time to try it out—Does this data truly assist Claude Code, or is it primarily only a human viewers that advantages from the outputs?

So I went into our help ticket system and picked a ticket that appeared complicated. I requested my investigation agent to take a look at the ticket and determine the issue. However this time I added an additional step into its directions:

4. Determine the affected flows in /docs/structure/flows

As a part of its evaluation, it mentioned:

Let me discover the structure flows to grasp how [redacted] and [redacted] ought to be dealt with:

Then it produced its evaluation accurately figuring out the stream and anticipated behaviors:

## Affected Move

**[BlahA Upload and BlahB History Thing](../structure/flows/[redacted]/README.md)**

The [redacted] workflow ought to populate [redacted] information through:
- [redacted] choice ([redacted] commonplace OR [redacted] enhanced primarily based on `[redacted]` flag)
- Parallel execution of: DomainA, DomainB, DomainC, DomainD
- Publishing `order.blahBlahed` occasion on completion
…

And for the subsequent steps, it wished to question the occasions printed by the system to confirm that what truly occurred matched the anticipated behaviors outlined within the stream:

### Step 1: Question [redacted] Occasions for Each [redacted]
**Goal:** Evaluate occasion historical past to determine what occurred otherwise between previous and new [redacted]
**What to search for:**
- `[redacted event name]` - Did [redacted] full for brand spanking new [redacted]?
- `[redacted event name]` - Had been [redacted] created?
- `[redacted event name]` - Had been [redacted] created?
- `[redacted event name]` - Did workflow full for brand spanking new [redacted]?
- `[redacted event name]` - Remaining affirmation occasion
- Any error/failure occasions associated to the workflow

Beforehand, Claude would have needed to analyze the codebase to work out what ought to have occurred. It takes a very long time and takes up loads of context window for complicated duties, and the evaluation must be verified.

Now, Claude is aware of instantly concerning the particular workflow and affected behaviors and may instantly start planning an investigation (if the documentation is correct sufficient). This evaluation is structured with the important thing data that I must see. I don’t must iterate with Claude to supply an evaluation within the format I want.

On this case, Claude didn’t resolve the issue instantly, however the dialog was extra like I may need with a group member—somebody who has a deeper understanding of how the system works and what is perhaps fallacious right here reasonably than simply utilizing Claude to investigate patterns in information, learn stack traces, or summarize textual content descriptions of the issue.

Accuracy and Hallucinations

I do assume it’s proper to be involved about accuracy. We don’t wish to make necessary selections about our system primarily based on incomplete or incorrect particulars. And there have been vital inaccuracies that I needed to spot and proper. (Think about if I didn’t know they had been fallacious.)

I explored the problem of accuracy in this later submitdisplaying how we are able to use deterministic instruments like ts-morph to construct the mannequin that people and AI can each profit from.

So right here’s what I’m pondering:

1. Generally we don’t want excellent accuracy. So long as the agent picks the proper path, it might probably reinspect sure particulars or dive deeper as wanted.
2. We will construct checks and steps in into our CI pipelines to replace issues.
3. Usually destroy and regenerate the flows (as soon as 1 / 4?).
4. Construct verification brokers or swarms.

Once I noticed an error and requested a brand new agent to investigate the stream for inaccuracies, it rescanned the code and located what I noticed. So I believe possibility 4 may be very credible—it’s simply extra effort to construct a verification system (which may make the general effort not value it).

However I’m undecided that is the optimum method of approaching the state of affairs. As a substitute…

The Subsequent Section of Platform Engineering

Avoiding the necessity to reverse engineer these flows shall be key. And I’m beginning to assume it will turn into the primary problem for platform engineering groups: How can we construct frameworks and tooling that expose our system as a graph of dependencies? Constructed into our platform in order that AI brokers don’t must reverse engineer; they will simply seek the advice of the supply of reality.

Issues ought to all occur transparently for software program engineers—you observe the platform paved path, and the whole lot simply works. Firms that do that, and particularly startups with no legacy, may immensely revenue from AI brokers.

Instruments like EventCatalog are in a robust place right here.

Instance Move

I simply requested Claude to translate one among my firm’s area flows right into a boring ecommerce instance. The design and naming is just not necessary; the kind of data and the visualization is what I’m attempting to convey.

Keep in mind, that is primarily based on someday of hacking round. I’m certain there are many enchancment alternatives right here. Let me know you probably have seen something higher.

The README

# Place Order with Cost and Success

**Standing**: Energetic
**Kind**: Write Operation
**Complexity**: Excessive
**Final Up to date**: 2025-10-19

## Overview

This stream paperwork the method of putting an order in an ecommerce system, together with cost authorization, stock reservation, and cargo creation. That is the baseline order placement expertise the place:
- Orders begin with `standing: 'pending'`
- Cost is allowed earlier than stock reservation
- Stock is reserved upon profitable cost
- Cargo is created after stock reservation

## Move Boundaries

**Begin**: Buyer clicks "Place Order" button on checkout web page

**Finish**: Publication of `transport.shipment-created` occasion (public occasion with `DOMAIN` scope)

**Scope**: This stream covers your complete course of from preliminary order submission by cost authorization, stock reservation, cargo creation, and all asynchronous unwanted effects triggered by these operations.

## Fast Reference

### API Endpoints

| Endpoint | Methodology | Repository | Function |
|----------|--------|------------|---------|
| `/checkout` | GET | storefront-app | Checkout web page |
| `/api/orders` | POST | order-api | Creates order |
| `/api/funds/authorize` | POST | payment-api | Authorizes cost |
| `/api/stock/reserve` | POST | inventory-api | Reserves stock |
| `/api/shipments` | POST | shipping-api | Creates cargo |
| `/api/orders/{orderId}/standing` | GET | order-api | Frontend polls for order standing |

### Occasions Reference

| Occasion Identify | Area | Topic | Function | Shoppers |
|------------|--------|---------|---------|-----------|
| `personal.orders.order.created` | ORDERS | order | Order creation | PaymentHandler, AnalyticsHandler |
| `personal.funds.cost.licensed` | PAYMENTS | cost | Cost licensed | InventoryReservationHandler |
| `personal.funds.cost.failed` | PAYMENTS | cost | Cost failed | OrderCancellationHandler |
| `personal.stock.inventory.reserved` | INVENTORY | inventory | Stock reserved | ShipmentCreationHandler |
| `personal.stock.inventory.inadequate` | INVENTORY | inventory | Inadequate inventory | OrderCancellationHandler |
| `personal.transport.cargo.created` | SHIPPING | cargo | Cargo created | NotificationHandler |
| `transport.shipment-created` | SHIPPING | cargo | **PUBLIC** Cargo created | Exterior customers |

### Database Tables

| Desk | Operation | Key Fields | Function |
|-------|-----------|------------|---------|
| `orders` | INSERT | orderId, customerId, standing="pending", totalAmount | Order mixture storage |
| `order_items` | INSERT | orderItemId, orderId, productId, amount, value | Order line objects |
| `funds` | INSERT | paymentId, orderId, quantity, standing="licensed" | Cost mixture storage |
| `inventory_reservations` | INSERT | reservationId, orderId, productId, amount | Stock reservation monitoring |
| `shipments` | INSERT | shipmentId, orderId, trackingNumber, standing="pending" | Cargo mixture storage |

### Area Operations

| Mixture | Methodology | Function |
|-----------|--------|---------|
| Order | `Order.create()` | Creates new order with pending standing |
| Order | `Order.confirmPayment()` | Marks cost as confirmed |
| Order | `Order.cancel()` | Cancels order on account of cost or stock failure |
| Cost | `Cost.authorize()` | Authorizes cost for order |
| Cost | `Cost.seize()` | Captures licensed cost |
| Stock | `Stock.reserve()` | Reserves inventory for order |
| Cargo | `Cargo.create()` | Creates cargo for order |

## Key Traits

| Facet | Worth |
|--------|-------|
| Order Standing | Makes use of `standing` subject: `'pending'` → `'confirmed'` → `'shipped'` |
| Cost Standing | Makes use of `standing` subject: `'pending'` → `'licensed'` → `'captured'` |
| Stock Technique | Reserve-on-payment method |
| Cargo Standing | Makes use of `standing` subject: `'pending'` → `'prepared'` → `'shipped'` |

## Move Steps

1. **Buyer** navigates to checkout web page in storefront-app (`/checkout`)
2. **Buyer** critiques order particulars and clicks "Place Order" button
3. **storefront-app UI** exhibits loading state with order affirmation message
4. **storefront-app** sends POST request to order-api (`/api/orders`)
  - Request consists of: customerId, objects (productId, amount, value), shippingAddress, billingAddress
5. **order-api** creates Order mixture with `standing: 'pending'` and persists to database
6. **order-api** creates OrderItem information for every merchandise within the order
7. **order-api** publishes `personal.orders.order.created` occasion
8. **order-api** returns orderId and order particulars to storefront-app
9. **storefront-app** redirects buyer to order affirmation web page

### Asynchronous Aspect Results - Cost Processing

10. **order-events-consumer** receives `personal.orders.order.created` occasion
11. **PaymentHandler** processes the occasion
   - Calls payment-api to authorize cost
12. **payment-api** calls exterior cost gateway (Stripe, PayPal, and many others.)
13. **payment-api** creates Cost mixture with `standing: 'licensed'` and persists to database
14. **payment-api** publishes `personal.funds.cost.licensed` occasion (on success)
   - OR publishes `personal.funds.cost.failed` occasion (on failure)

### Asynchronous Aspect Results - Stock Reservation

15. **payment-events-consumer** receives `personal.funds.cost.licensed` occasion
16. **InventoryReservationHandler** processes the occasion
   - Calls inventory-api to order inventory
17. **inventory-api** masses Stock mixture for every product
18. **inventory-api** calls `Stock.reserve()` for every order merchandise
   - Validates ample inventory obtainable
   - Creates reservation file
   - Decrements obtainable inventory
19. **inventory-api** creates InventoryReservation information and persists to database
20. **inventory-api** publishes `personal.stock.inventory.reserved` occasion (on success)
   - OR publishes `personal.stock.inventory.inadequate` occasion (on failure)

### Asynchronous Aspect Results - Cargo Creation

21. **inventory-events-consumer** receives `personal.stock.inventory.reserved` occasion
22. **ShipmentCreationHandler** processes the occasion
   - Calls shipping-api to create cargo
23. **shipping-api** creates Cargo mixture with `standing: 'pending'` and persists to database
24. **shipping-api** calls exterior transport service API to generate monitoring quantity
25. **shipping-api** updates Cargo with trackingNumber
26. **shipping-api** publishes `personal.transport.cargo.created` occasion
27. **shipping-events-consumer** receives `personal.transport.cargo.created` occasion
   - **ShipmentCreatedPublicHandler** processes the occasion
   - Masses cargo from repository to get full cargo particulars
   - Publishes public occasion: `transport.shipment-created`
   - **This marks the END of the stream**

### Order Standing Updates

28. All through the stream, order-api receives occasions and updates order standing:
   - On `personal.funds.cost.licensed`: Updates order with paymentId
   - On `personal.stock.inventory.reserved`: Updates order to `standing: 'confirmed'`
   - On `personal.transport.cargo.created`: Updates order to `standing: 'shipped'`

### Failure Situations

**Cost Failure**:
- On `personal.funds.cost.failed`: OrderCancellationHandler cancels order
- Order standing up to date to `'cancelled'`
- Buyer notified through e-mail

**Stock Failure**:
- On `personal.stock.inventory.inadequate`: OrderCancellationHandler cancels order
- Cost authorization is voided
- Order standing up to date to `'cancelled'`
- Buyer notified through e-mail with choice to backorder

## Repositories Concerned

- **storefront-app**: Frontend UI
- **order-api**: Order area
- **payment-api**: Cost area
- **inventory-api**: Stock area
- **shipping-api**: Transport and success area
- **notification-api**: Buyer notifications

## Associated Flows

- **Course of Refund**: Move for dealing with order refunds and returns
- **Replace Cargo Standing**: Move for monitoring cargo supply standing
- **Stock Reconciliation**: Move for syncing stock counts with warehouse techniques

## Occasions Produced

| Occasion | Function |
|-------|---------|
| `personal.orders.order.created` | Notifies {that a} new order has been created |
| `personal.funds.cost.licensed` | Notifies that cost has been licensed |
| `personal.funds.cost.failed` | Notifies that cost authorization failed |
| `personal.stock.inventory.reserved` | Notifies that stock has been reserved |
| `personal.stock.inventory.inadequate` | Notifies that inadequate stock is obtainable |
| `personal.transport.cargo.created` | Inside occasion that cargo has been created |
| `transport.shipment-created` | **Public occasion** that cargo is created and prepared for service pickup |

## Occasion Shoppers

### `personal.orders.order.created` Shoppers

#### 1. order-events-consumer

**Handler**: `PaymentHandler`

**Function**: Initiates cost authorization course of

**Actions**:
- Subscribes to occasion
- Calls `AuthorizePayment` use case
- Invokes payment-api to authorize cost with cost gateway
- Publishes cost outcome occasion

#### 2. order-events-consumer

**Handler**: `AnalyticsHandler`

**Function**: Tracks order creation for analytics

**Actions**:
- Subscribes to occasion
- Sends order information to analytics platform
- Updates conversion monitoring

### `personal.funds.cost.licensed` Shopper

#### payment-events-consumer

**Handler**: `InventoryReservationHandler`

**Function**: Reserves stock after profitable cost

**Actions**:
- Subscribes to occasion
- Calls `ReserveInventory` use case
- Masses order particulars
- Calls inventory-api to order inventory for every merchandise
- Publishes stock reservation outcome occasion

### `personal.funds.cost.failed` Shopper

#### payment-events-consumer

**Handler**: `OrderCancellationHandler`

**Function**: Cancels order when cost fails

**Actions**:
- Subscribes to occasion
- Calls `CancelOrder` use case
- Updates order standing to 'cancelled'
- Triggers buyer notification

### `personal.stock.inventory.reserved` Shopper

#### inventory-events-consumer

**Handler**: `ShipmentCreationHandler`

**Function**: Creates cargo after stock reservation

**Actions**:
- Subscribes to occasion
- Calls `CreateShipment` use case
- Calls shipping-api to create cargo file
- Integrates with transport service API for monitoring quantity
- Publishes cargo created occasion

### `personal.stock.inventory.inadequate` Shopper

#### inventory-events-consumer

**Handler**: `OrderCancellationHandler`

**Function**: Cancels order when stock is inadequate

**Actions**:
- Subscribes to occasion
- Calls `CancelOrder` use case
- Voids cost authorization
- Updates order standing to 'cancelled'
- Triggers buyer notification with backorder possibility

### `personal.transport.cargo.created` Shopper

#### shipping-events-consumer

**Handler**: `ShipmentCreatedPublicHandler`

**Function**: Converts personal cargo occasion to public occasion

**Actions**:
- Subscribes to `personal.transport.cargo.created` occasion
- Masses cargo from repository
- Publishes public occasion: `transport.shipment-created`

**Handler**: `NotificationHandler`

**Function**: Notifies buyer of cargo creation

**Actions**:
- Subscribes to occasion
- Sends affirmation e-mail with monitoring quantity
- Sends SMS notification (if opted in)

## Database Operations

### orders Desk
- **Operation**: INSERT (through upsert)
- **Key Fields**: orderId, customerId, standing="pending", totalAmount, createdAt
- **Repository**: `OrderRepository`

### order_items Desk
- **Operation**: INSERT (batch)
- **Key Fields**: orderItemId, orderId, productId, amount, value
- **Repository**: `OrderItemRepository`

### funds Desk
- **Operation**: INSERT (through upsert)
- **Key Fields**: paymentId, orderId, quantity, standing="licensed", gatewayTransactionId
- **Repository**: `PaymentRepository`

### inventory_reservations Desk
- **Operation**: INSERT (through upsert)
- **Key Fields**: reservationId, orderId, productId, amount, reservedAt
- **Repository**: `InventoryReservationRepository`

### shipments Desk
- **Operation**: INSERT (through upsert)
- **Key Fields**: shipmentId, orderId, trackingNumber, standing="pending", service
- **Repository**: `ShipmentRepository`

## Exterior Integrations

- **Cost Gateway Integration**: Authorizes and captures funds through Stripe API
 - Endpoint: `/v1/payment_intents`
 - Synchronous name throughout cost authorization

- **Transport Service Integration**: Generates monitoring numbers through service API
 - Endpoint: `/api/v1/shipments`
 - Synchronous name throughout cargo creation

## What Occurs After This Move

This stream ends with the publication of the `transport.shipment-created` public occasion, which marks the order as totally processed and prepared for service pickup.

### State at Move Completion
- Order: `standing: 'shipped'`
- Cost: `standing: 'licensed'` (shall be captured on precise cargo)
- Stock: Inventory reserved and decremented
- Cargo: `standing: 'pending'`, trackingNumber assigned

### Subsequent Steps
After this stream completes:
- Warehouse group picks and packs the order
- Service picks up the cargo
- Transport standing updates stream tracks supply
- Cost is captured upon confirmed cargo
- Buyer can monitor order through monitoring quantity

### Exterior System Integration
As soon as the `transport.shipment-created` occasion is printed:
- Warehouse administration system begins choose/pack course of
- Buyer notification system sends monitoring updates
- Logistics companions obtain cargo manifest
- Analytics techniques monitor success metrics

## Diagram

See [diagram.mermaid](./diagram.mermaid) for the whole visible stream displaying the development by techniques with horizontal swim lanes for every service.

The Mermaid:

flowchart LR
   Begin([Customer clicks Place Order
on checkout page])

   subgraph storefront["🌐 storefront-app"]
       path LR
       ShowCheckout[Show checkout page]
       CustomerReview[Customer reviews order]
       ShowConfirmation[Show order
confirmation page]
   finish

 CustomerWaitsForShipment([Customer receives
shipment notification])

subgraph orderService["📦 order-api"]
       path LR
       CreateOrderEndpoint["POST /api/orders"]
       OrderCreate[Order.create]
       OrderDB[(Database:
INSERT orders,
order_items)]
       PublishOrderCreated["Publish: private.orders
.order.created"]
       ReceivePaymentAuth["Receive: private.payments
.payment.authorized"]
       UpdateOrderPayment[Update order
with paymentId]
       ReceiveStockReserved["Receive: private.inventory
.stock.reserved"]
       OrderConfirm[Order.confirmPayment]
       UpdateOrderConfirmed[(Database:
UPDATE orders
status="confirmed")]
       ReceiveShipmentCreated["Receive: private.shipping
.shipment.created"]
       UpdateOrderShipped[(Database:
UPDATE orders
status="shipped")]
   finish

 subgraph paymentService["💳 payment-api"]
       path LR
       ReceiveOrderCreated["Receive: private.orders
.order.created"]
       AuthorizeEndpoint["POST /api/payments/
authorize"]
       PaymentGateway["External: Payment
Gateway API
(Stripe)"]
       PaymentAuthorize[Payment.authorize]
       PaymentDB[(Database:
INSERT payments)]
       PublishPaymentAuth["Publish: private.payments
.payment.authorized"]
   finish

 subgraph inventoryService["📊 inventory-api"]
       path LR
       ReceivePaymentAuth2["Receive: private.payments
.payment.authorized"]
       ReserveEndpoint["POST /api/inventory/
reserve"]
       InventoryReserve[Inventory.reserve]
       InventoryDB[(Database:
INSERT inventory_reservations
UPDATE product stock)]
       PublishStockReserved["Publish: private.inventory
.stock.reserved"]
   finish

 subgraph shippingService["🚚 shipping-api"]
       path LR
       ReceiveStockReserved2["Receive: private.inventory
.stock.reserved"]
       CreateShipmentEndpoint["POST /api/shipments"]
       CarrierAPI["External: Shipping
Carrier API
(FedEx/UPS)"]
       ShipmentCreate[Shipment.create]
       ShipmentDB[(Database:
INSERT shipments)]
       PublishShipmentCreated["Publish: private.shipping
.shipment.created"]
       ReceiveShipmentCreatedPrivate["Receive: private.shipping
.shipment.created"]
       LoadShipment[Load shipment
from repository]
       PublishPublicEvent["Publish: shipping
.shipment-created"]
       FlowEnd([Flow End:
Public event published])
   finish

   Begin --> ShowCheckout
   ShowCheckout --> CustomerReview
   CustomerReview --> CreateOrderEndpoint
   CreateOrderEndpoint --> OrderCreate
   OrderCreate --> OrderDB
   OrderDB --> PublishOrderCreated
   PublishOrderCreated --> ShowConfirmation

   PublishOrderCreated -.-> ReceiveOrderCreated
   ReceiveOrderCreated --> AuthorizeEndpoint
   AuthorizeEndpoint --> PaymentGateway
   PaymentGateway --> PaymentAuthorize
   PaymentAuthorize --> PaymentDB
   PaymentDB --> PublishPaymentAuth

   PublishPaymentAuth -.-> ReceivePaymentAuth
   ReceivePaymentAuth --> UpdateOrderPayment

   PublishPaymentAuth -.-> ReceivePaymentAuth2
   ReceivePaymentAuth2 --> ReserveEndpoint
   ReserveEndpoint --> InventoryReserve
   InventoryReserve --> InventoryDB
   InventoryDB --> PublishStockReserved

   PublishStockReserved -.-> ReceiveStockReserved
   ReceiveStockReserved --> OrderConfirm
   OrderConfirm --> UpdateOrderConfirmed

   PublishStockReserved -.-> ReceiveStockReserved2
   ReceiveStockReserved2 --> CreateShipmentEndpoint
   CreateShipmentEndpoint --> CarrierAPI
   CarrierAPI --> ShipmentCreate
   ShipmentCreate --> ShipmentDB
   ShipmentDB --> PublishShipmentCreated

   PublishShipmentCreated -.-> ReceiveShipmentCreated
   ReceiveShipmentCreated --> UpdateOrderShipped

   PublishShipmentCreated -.-> ReceiveShipmentCreatedPrivate
   ReceiveShipmentCreatedPrivate --> LoadShipment
   LoadShipment --> PublishPublicEvent
   PublishPublicEvent --> FlowEnd

   FlowEnd -.-> CustomerWaitsForShipment

   type Begin fill:#e1f5e1
   type FlowEnd fill:#ffe1e1
   type CustomerWaitsForShipment fill:#e1f5e1
   type PublishOrderCreated fill:#fff4e1
   type PublishPaymentAuth fill:#fff4e1
   type PublishStockReserved fill:#fff4e1
   type PublishShipmentCreated fill:#fff4e1
   type PublishPublicEvent fill:#fff4e1
   type OrderDB fill:#e1f0ff
   type PaymentDB fill:#e1f0ff
   type InventoryDB fill:#e1f0ff
   type ShipmentDB fill:#e1f0ff
   type UpdateOrderConfirmed fill:#e1f0ff
   type UpdateOrderShipped fill:#e1f0ff
   type PaymentGateway fill:#ffe1f5
   type CarrierAPI fill:#ffe1f5