# How to approve payments

> A Pachca use case. An employee sends an invoice through the bot's form to the "Payments" chat, the manager clicks "Approve" or "Reject", and the accountant attaches the payment order in the thread under the invoice.

> This is the Markdown version of https://pachca.com/en/scenarios/soglasovanie-platezhey for AI agents. The API methods named here are documented at https://dev.pachca.com/llms-en.txt — open it before calling the API. Other use cases are listed at https://pachca.com/en/llms.txt.

## What you'll get

1. An employee clicks "Submit invoice" in the bot's pinned message and fills out the form.
2. The bot posts the invoice in the "Payments" chat with "Approve" and "Reject" buttons. The bot picks the approver based on the budget line.
3. The manager clicks "Approve". The bot @mentions the accountant in the thread under the invoice and gives the payment deadline.
4. The accountant pays the invoice, attaches the payment order in the thread and adds a ✅ reaction to the invoice.

## What you need before you start

- Pachca access as an administrator with the scopes `search:users` or `users:read`, `search:chats`, `chats:create`, `chat_members:write`, `bots:read`, `bots:write`, `messages:create`, `messages:read`, `pins:write`. Signing in is covered in the rules below.
- n8n or a developer's service where the bot's handler will run.

## If you're an AI agent: working rules

### Who does what

- You do everything the instructions name an API method for. Don't ask the user to create a chat, a bot or a message by hand.
- Ask the user only to sign in to Pachca and to do what is listed in "Ask the user to do by hand".
- If you have no terminal, say so right away and don't pretend you set it up. Walk the user through the steps for people on the use case page and help with the template or the handler code.

### How to talk to the user

- The user is not a developer. Write briefly and in plain words. Don't mention API methods, scopes, response codes, `id`s or CLI profiles. Say "permissions" instead of "scopes" and "the program behind the bot" instead of "handler".
- Don't report your checks. A message contains only three things: what is done, what you need from the user, what you'll do next.
- Don't ask for what you can find out through the API or what is easy to change later. Take the value from the instructions and name it.
- Take the bot's message texts from the instructions or write them yourself and carry on. Show them in your final message and offer to change them. Don't wait for approval.
- Ask the questions from "Ask the user" in the same words.

### Your first message to the user

It has three parts. The first two together take at most five lines.

1. What the user will get: one or two lines.
2. What you will create yourself: the chat, the bot and the messages, with the names from the instructions. Word anything that depends on the user's choice as a condition: "if you choose the bot, I'll also create…".
3. "What I need from you": signing in to Pachca, if the user isn't signed in yet, and the questions from "Ask the user". If the use case or one of its options needs n8n, ask here whether the user has it and ask for access right away in the words from the "n8n" section below: "if you have n8n, send me…".

If part of the result appears only after a manual step by the user, say so in one line: "you'll schedule the retro questions yourself, I'll show you how".

The user's answers are their consent to the plan. Start the setup right after them, without asking for a second confirmation.

### Access to Pachca

- The user doesn't need to issue a token or send it in the chat. Before your first message, check the login: `npx -y @pachca/cli@latest auth status`. If there is none, ask the user to run `npx -y @pachca/cli@latest auth login` in their own terminal. The CLI shows a code; the user enters it in the browser and confirms access. Write the commands with `@latest`: without it an old cached CLI version may start, and it asks to paste a token instead of signing in through the browser.
- This login has the same rights as the user's role. Compare them with the scopes in "What you need before you start" yourself: `npx -y @pachca/cli@latest api GET /oauth/token/info` shows the scopes. If something is missing, say in plain words what you won't be able to do, for example "I can't send messages". There are two ways out: add this permission to the token in Pachca, under "Automations" → "API", or sign in again as the workspace owner or an administrator.
- If `auth status` shows `scopes: null`, it doesn't mean there are no rights: look at `GET /oauth/token/info`. The checks in these rules also need `search:chats`, `bots:read` and `profile:read`.
- When the user says "me", they mean the owner of the login. `GET /profile` returns their `id` and nickname.
- Call the API with `npx -y @pachca/cli@latest api <METHOD> <path> -o json`. Write the full command in every call; don't put it into a shell variable.
- Pass query parameters as `--query key=value`, for example `--query query=Purchasing`. The CLI silently drops a parameter without a key and returns the whole list, so it's easy to conclude that the chat already exists.
- Pass the request body with `--data` or `--input`. Almost every write method wraps the body in an object: `chat` for `POST /chats`, `message` for `POST /messages`, `task` for `POST /tasks`, `group_tag` for `POST /group_tags`, `user` for `PUT /users/{id}`, `webhook` for bots. `--describe` shows the wrapper; write its path with `{id}`, not with a number. Without the wrapper, `POST /chats` creates the chat but silently adds no members.
- Don't print tokens or bots' incoming webhook URLs in the chat. A bot's token is shown only once, when it's created: save it to a file.

### n8n

- If the user has no n8n, say that it comes as the hosted n8n Cloud or can be installed on their own server, and give the link for installing the Pachca nodes: https://dev.pachca.com/guides/n8n/setup.md. These instructions don't cover installing n8n. If they have an option without n8n, suggest starting with it and coming back to the bot once n8n is there.
- If the user has n8n, ask for access in these words: "Send me your n8n address: the link you open it with in the browser. Don't send the key in the chat. In n8n, open Settings → n8n API → Create an API key and copy the key. Right after that, run the command below in your terminal exactly as it is; you don't need to put anything into it. It saves the copied key to a file and prints nothing. Then write 'key saved'." The command for macOS: `pbpaste > ~/n8n-key.txt`. For another system, pick the matching one.
- Build everything in n8n on the official Pachca nodes, `n8n-nodes-pachca`. Don't use the `HTTP Request` node for Pachca API calls.

### Setup

- Take API methods from https://dev.pachca.com/llms-en.txt, don't rely on memory. The command `npx -y @pachca/cli@latest api <METHOD> <path> --describe` shows a method's schema.
- The Pachca skills cover the call order and error handling for chats, bots and forms: `npx skills add pachca/openapi`. Install them when you need them, without asking the user.
- Before creating anything, check whether the chat and the bot already exist: `GET /search/chats`, `GET /bots`. If they do, ask whether to set them up or create new ones.
- `POST /group_tags` creates an empty tag. `PUT /users/{id}` with `list_tags` assigns it to an employee; it needs the `users:update` scope. The field replaces the whole set of tags: first read the employee's current tags with `GET /users/{id}` and send them together with the new one. While the tag has no members, mentioning it notifies no one.
- If a method returns an error, stop and tell the user in plain words what failed and what you need to continue.
- The messages you post yourself and the ones the bot sends must be easy to read on a screen, without overdoing spacing or emphasis. Make the heading bold and start the text on the next line. Write connected text as one paragraph. Put rules and steps on numbered lines one under another and separate them from the intro with a single empty line. A short message needs no other empty lines. In a card, make the field labels bold and put the fields on consecutive lines. Use bold only for the heading and the field labels. Pachca markup has no lists or tables: the numbers at the start of lines stay plain text. A sample:

  ```text
  **Retro rules**
  On the last day of the sprint a message with questions arrives here. We reply in the thread under it.

  1. Each point is a separate message.
  2. We add 👍 to what is worth discussing.
  3. The facilitator posts the outcomes in one message and pins it.
  ```
- A pin can't be checked through the API: only a successful `POST /messages/{id}/pin` response confirms it.
- If you sent service messages to a chat to check a bot, such as `/start`, delete them: `DELETE /messages/{id}`. Don't delete messages with rules and templates.
- At the end, say what was created, what is left for the user to do by hand and how to check that the use case works.
- To undo the setup: `DELETE /bots/{id}` deletes the bot, `PUT /chats/{id}/archive` sends the chat to the archive.

## How to set up the use case with the user

### 1. Ask the user

Ask these questions in these words:

1. Do you have n8n? The program behind the bot will run there. If not, your developer can build it.
2. Who submits invoices, which managers approve them and who are the accountants? Send me the names and I'll add everyone to the "Payments" chat.
3. What are your budget items, and who approves invoices for each?
4. Which accountant does the bot mention after approval?

Make the invoice file, the amount and the budget item required in the form and leave the other fields optional. Say so in your final message and offer to change it.

### 2. Do it yourself through the Pachca API

1. Find the `id` of the employees, managers and accountants: `GET /search/users` or `GET /users`.
2. Create the chat: `POST /chats` with `name: "Payments"` and `member_ids`. Take the chat's `id` from the response: the handler will need it.
3. Create the bot: `POST /bots` with `name: "Payments"`, a nickname ending in `_bot`, `trigger_on: "commands"`, `commands: ["/start"]` and `events: ["message_new", "button_click"]`. From the response, save the bot's `id` (also its `user_id`) and `access_token`.
4. Add the bot to the chat: `POST /chats/{id}/members` with the bot's `id` in `member_ids`.
5. Offer to post the rules in the chat: `POST /messages`. The accountant pays only approved invoices, attaches the payment order in the thread and adds a ✅ reaction to the invoice.

### 3. Build the handler

The handler receives the bot's events and replies with the bot's token. Build it in n8n or hand this description to a developer. A ready-made example with a form and buttons is in the time-off use case. Swap its fields and buttons.

- The `/start` message in the "Payments" chat. The bot replies with a message that has a "Submit invoice" button: `POST /messages` with `buttons`.
- The "Submit invoice" click. The bot opens the form: `POST /views/open` with the `trigger_id` from the click event. The `trigger_id` is valid for 3 seconds.
- Form fields: invoice file, vendor, purpose, amount, budget line, due date. Their blocks in `view.blocks`: `file_input`, `input`, `select`, `date`.
- Form submission. The bot posts the invoice in the "Payments" chat with "Approve" and "Reject" buttons. The bot attaches the invoice file to the message in `files`; each file needs `key`, `name`, `file_type`, `size`. How to upload a file: https://dev.pachca.com/api/file-uploads.md
- The "Approve" or "Reject" click. The bot writes the decision in the thread under the invoice: `POST /messages/{id}/thread`, then `POST /messages`. After "Approve", the bot @mentions the accountant in the thread and gives the payment deadline.
- In the handler, each budget line has the manager who approves its invoices. The bot picks the approver by the budget line from the form. Event reference: https://dev.pachca.com/guides/webhook/events.md

### The handler in n8n

Build the handler on version 2 of the Pachca nodes, `n8n-nodes-pachca`. They must be installed in the user's n8n: https://dev.pachca.com/guides/n8n/setup.md

A complete working workflow with a form, buttons and thread replies: https://pachca.com/scenarios-agent/propusk-bot-n8n.json. Its texts are in Russian. Use it as the base and replace the form fields, buttons, texts and branches for your use case. The file has placeholders: `CHAT_ID`, `MANAGERS`, `CREDENTIAL_ID` and `NEW-UUID`. Take node parameter names from it and from the list below. Some examples on dev.pachca.com use different names, and a workflow built from them won't work.

What to build from:

- `Pachca Trigger` receives the bot's events. Use one per workflow: a bot has a single webhook address. The `event` parameter takes one value; set it to `*`, which means all events. Set `webhookSetup` to `manual`: you will set the bot's address yourself. The node needs its own `webhookId`, a new UUID.
- A `Code` node after the trigger parses the event and picks a branch. A new message: `type: "message"`, `event: "new"`, the text is in `content`. A button press: `type: "button"`, the button's value is in `data`, with `trigger_id` and `message_id` next to it. A form submission: `type: "view"`, `event: "submit"`, the form's `callback_id`, field values in `data` by field name. `user_id` shows who acted. Event fields: https://dev.pachca.com/guides/webhook/events.md
- `Switch` routes events by the branch from the `Code` node.
- Form: the `Pachca` node, `resource: "form"`, `operation: "create"`. The title goes into `formTitle`; `triggerId` comes from the button press event and is valid for three seconds. `formBuilderMode: "json"`, the fields go into `formBlocks` as a JSON string. `callbackId`, `submitText` and `closeText` sit inside `additionalFields`. Block types: https://dev.pachca.com/guides/forms/blocks.md
- Message: `resource: "message"`, `operation: "create"`, `entityType` and `entityId`, the text in `content`. Post to a chat with `entityType: "discussion"`; message an employee directly with `entityType: "user"` and their `user_id` in `entityId`. In the sample, the button after `/start` goes to the chat: if the bot should reply in direct messages in your use case, change this. Buttons: `buttonLayout: "raw_json"` and `rawJsonButtons` as a JSON string. It is an array of rows, each row an array of buttons with `text` and `data`. Mention an employee as `<@user_id>`.
- A reply in the thread under a message. First `resource: "thread"`, `operation: "create"` with `threadMessageId`: the `message_id` of the message that needs a thread. The node returns the thread's `id`. Then a message with `entityType: "thread"` and that `id` in `entityId`.
- A button press inside a thread brings the thread's `chat_id`, but a reply needs the thread's `id`. Put the thread's `id` into the `data` of the buttons you post in the thread.
- If not everyone may press a button, compare `user_id` from the event with the list in the handler spec and send nothing on someone else's press.

- Chat members: `resource: "member"`, `operation: "getAll"`, the chat in the `id` parameter, `returnAll: true`, `simplify: false`. The bot itself is in this list with the `bot` flag: filter it out.
- A schedule is started by a `Schedule Trigger` node with a `cronExpression` rule.

The sample stores nothing: everything a reply needs is in the buttons' `data`, namely the action and the author's `id`. If the use case has to remember a little data, such as a request number counter or who has already answered, use the workflow's static data: `$getWorkflowStaticData('global')` in a `Code` node. It is saved only on runs of an active workflow, not on manual runs in the editor. Name this decision to the user in your final message. Keep meeting room schedules, registers and anything that must survive recreating the workflow in an external table: choose it together with the user.

Steps:

1. Build the workflow file. Keep only `name`, `nodes`, `connections` and `settings`: the n8n API rejects other fields. Check that the JSON is valid and that node names in `connections` and in expressions match the names in `nodes`.
2. Get the n8n address and API key as described in the rules above. Requests to the n8n API carry the `X-N8N-API-KEY` header.
3. Create a Pachca credential in n8n: `POST /api/v1/credentials` with `type: "pachcaApi"`. In `data`, put `accessToken` with the bot token and `baseUrl` with `https://api.pachca.com/api/shared/v1`. `GET /api/v1/credentials/schema/pachcaApi` shows the other required fields. If `allowedHttpRequestDomains` is among them, set it to `all`. Put the `id` and name of this credential into every Pachca node in the file.
4. Upload the workflow: `POST /api/v1/workflows`. Activate it: `POST /api/v1/workflows/{id}/activate`.
5. Set the bot's webhook address: `PUT /bots/{id}` with `outgoing_url`. The address is the n8n address, then `/webhook/`, the `webhookId` of the `Pachca Trigger` node and `/webhook`.
6. To check a scheduled run without waiting, temporarily set the schedule to the next minute, wait for the run and set it back.
7. If there is no n8n API key or a step fails, give the file to the user. They paste its contents into a new workflow, create a credential with the bot token, select it in every Pachca node and activate the workflow. Ask for the Production URL of the `Pachca Trigger` node and set it for the bot yourself.

### 4. Connect the bot to the handler

Put the handler's URL in the bot's outgoing webhook: `PUT /bots/{id}` with `outgoing_url` using a personal token, or `PUT /bot/webhook` using the bot's token.

### 5. Ask the user to do by hand

- Agree with the team who approves which invoices and how quickly. For example, a department head approves invoices for their own budget line, and large invoices then go to the CFO for approval too.
- Send `/start` in the "Payments" chat.

### 6. Pin the bot's message

Request `GET /messages` with the chat's `chat_id`. Pin the bot's reply with the "Submit invoice" button: `POST /messages/{id}/pin`.

### 7. Check

- Ask the user to click "Submit invoice" in the pinned message and submit a test invoice.
- Request `GET /messages` with the chat's `chat_id` and make sure the test invoice showed up in the chat.

## Troubleshooting

- The bot doesn't respond to `/start`. Request `GET /bots/{id}` and check `outgoing_url` and `message_new` in `events`.
- The "Submit invoice" button doesn't open the form. `button_click` is missing from the bot's `events`.
- The form was submitted, but the invoice isn't in the chat. Check that the handler got the chat's `id`. If it's there, ask the user to open the bot settings, the "Outgoing webhook" tab, and check the "Form submissions" event.

## Links

- The use case page with the demo and instructions for people: https://pachca.com/en/scenarios/soglasovanie-platezhey
- The time-off use case: https://pachca.com/en/scenarios/soglasovanie-otpuska
- Buttons in bot messages: https://dev.pachca.com/guides/buttons.md
- Forms: https://dev.pachca.com/guides/forms/overview.md
- Outgoing webhooks and event types: https://dev.pachca.com/guides/webhook/events.md
- File uploads: https://dev.pachca.com/api/file-uploads.md