> ## Documentation Index
> Fetch the complete documentation index at: https://www.plain.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# How credits work

> Credits pay for usage-based features in Plain, such as Ari resolutions, Sidekick sessions, AI workflows, and External Agents.

Each workspace gets a monthly allowance of credits with its [plan](/docs/product/billing/pricing#prices-and-included-credits), and Plain's usage-based features draw from it as you use them. When the allowance runs out, you can buy top-up credits.

## Your monthly allowance

Your included allowance is designed to help you get started with Ari, Sidekick, and Plain's other usage-based features.

Your [included credits](/docs/product/billing/pricing#prices-and-included-credits) reset each month on your billing anniversary. If your annual plan starts on April 15, your next allowance starts on May 15.

Unused included credits expire when your allowance resets. They don't roll over.

## What uses credits

Ari, External Agents, Sidekick, and AI workflows use credits. Ari and External Agents use a fixed amount for each action, and Sidekick and AI workflows use a variable amount that depends on the work. Nothing else in Plain uses credits.

| Action | Type | When credits are used | Credits |
| - | - | - | - |
| Ari resolution | Fixed | Ari resolves a thread. A thread counts as resolved if it isn't reopened within 7 days of being closed | 100 |
| External Agent discussion | Fixed | An External Agent discussion starts to investigate something in Plain. The rate is the same however long the session runs | 15 |
| External Agent thread assignment | Fixed | You assign an External Agent to a thread, for example to send a reply. The rate is the same regardless of how long or how many times the agent is involved | 15 |
| Sidekick session | Variable | A Sidekick session runs | 15–300+ |
| AI workflow run | Variable | A workflow that uses AI runs | 15–300+ |

### Fixed actions

A fixed action uses the same number of credits however complex the work is.

Two products complete fixed actions: Ari and External Agents.

[Ari](/docs/product/agents/ari) is Plain's built-in, customer-facing agent. An [External Agent](/docs/product/agents/bring-your-own-agent) is one you define, build, and run on Plain's infrastructure: External Agents are how you bring your own agent to Plain. They're available on the [Frontier plan](/docs/product/billing/pricing#frontier).

An External Agent can use credits for a discussion, a thread assignment, or both, depending on how it's involved.

### Variable actions

A variable action uses credits based on the request, the context, the tools, and the number of steps. A short task uses fewer credits. Work that needs more investigation, tools, context, or judgment uses more.

Two products complete variable actions: Sidekick and AI workflows.

[Sidekick](/docs/product/agents/sidekick) is Plain's built-in internal agent. It helps your team investigate questions, gather context, and do work your customers don't see. A Sidekick session starts when a user opens one or a [workflow starts one](/docs/product/agents/sidekick/in-workflows), and it ends 24 hours after its last activity.

AI workflows are [workflows](/docs/product/workflows) that use AI. Each run is billed once the workflow completes.

These examples show what variable work costs:

| Size | Example | Approximate credits |
| - | - | - |
| Small | Summarize a thread | 15 |
| Small | Find threads that replied to an update | 50 |
| Small | Add code or docs context to a thread | 50 |
| Small | Rank the most urgent open threads | 50 |
| Medium | Investigate a straightforward bug | 200 |
| Medium | Investigate what caused a spike on a Plain chart | 200 |
| Medium | Clean up 30 Help Center articles | 300 |
| Large | Investigate and explain product feature behavior with code access | 1,000 |
| Large | Debug a complex bug over several turns and tools, with code access | 2,000 |

The examples are a guide. Similar requests can use different amounts of credits.

## When you run out of credits

Features that use credits stop working until you add more credits. You can buy top-up credits, or increase your monthly allowance.

### Buy top-up credits

Buy top-up credits in your workspace's Billing settings. They cost \$10 for each block of 1,000 credits, and the minimum purchase is 1,000 credits.

Top-up credits don't expire. They stay in your account until you use them.

### Increase your monthly allowance

If you need more credits every month, you can increase your included allowance. Email [sales@plain.com](mailto:sales@plain.com) to discuss your requirements and volume discounts.

Extra included credits apply for the rest of your billing term and are billed upfront. They're allocated monthly, and unused credits expire at the end of each month.

## View your usage

Go to [**Settings → Usage**](https://app.plain.com/~/settings/usage) to see an itemized list of the actions that used credits.