[Docs index](/docs.md) / [Sandcastles](/docs/sandcastles/overview.md) / Use Cases and Playbooks

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# Use Cases and Playbooks

These playbooks walk through building real internal tools as sandcastles. Each one starts from a conversation with the AI and ends with a working app your team can use — complete with persistent data, a linked subagent for automation, and a clear path to extend.

## Playbooks

### [Playbook: Build a Purchase Approval Tracker](playbook-purchase-approval-tracker.md)

Purchase requests live in email threads, spreadsheets, and Slack messages. This playbook walks you through building a kanban-style approval tracker where requesters submit, managers approve, finance signs off, and procurement orders — all in one app with a full audit trail.

### [Playbook: Build a Vendor Performance Scorecard](playbook-vendor-performance-scorecard.md)

Your procurement team evaluates vendors by gut feel because the data is scattered across the ERP, the 3PL portal, and a spreadsheet someone started two years ago. This playbook walks you through building a scorecard app that consolidates delivery performance, payment history, and quality metrics into a single ranked view.

### [Playbook: Build a Budget Variance Dashboard](playbook-budget-variance-dashboard.md)

Finance publishes a budget at the start of the quarter. By week three nobody knows where actual spend stands relative to plan. This playbook walks you through building a dashboard that shows variance by department and cost center, with drill-downs and alerts when spend exceeds threshold.

### [Playbook: Build a Contract Renewal Tracker](playbook-contract-renewal-tracker.md)

Contract renewals sneak up on you. Somebody notices the auto-renew date three days out, and the team scrambles. This playbook walks you through building a tracker that centralizes contract metadata, shows a renewal calendar, and uses a subagent to send reminders before deadlines arrive.

## Related guides

- [Sandcastles overview](overview.md)
- [Creating a sandcastle](creating-a-sandcastle.md)
- [Editing a sandcastle](editing-a-sandcastle.md)
- [Managing sandcastle data](managing-sandcastle-data.md)
- [Troubleshooting](troubleshooting.md)

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## Navigation

### In this section: Sandcastles

- [Sandcastles](/docs/sandcastles/overview.md)
- **Use Cases and Playbooks** (current)
- [Troubleshooting](/docs/sandcastles/troubleshooting.md)
- [Creating a Sandcastle](/docs/sandcastles/creating-a-sandcastle.md)
- [Editing a Sandcastle](/docs/sandcastles/editing-a-sandcastle.md)
- [Managing Sandcastle Data](/docs/sandcastles/managing-sandcastle-data.md)

#### Playbooks

- [Playbook: Build a Budget Variance Dashboard](/docs/sandcastles/playbook-budget-variance-dashboard.md)
- [Playbook: Build a Contract Renewal Tracker](/docs/sandcastles/playbook-contract-renewal-tracker.md)
- [Playbook: Build a Purchase Approval Tracker](/docs/sandcastles/playbook-purchase-approval-tracker.md)
- [Playbook: Build a Vendor Performance Scorecard](/docs/sandcastles/playbook-vendor-performance-scorecard.md)

### Other sections

- [MCP Servers](/docs/mcp-servers/overview.md)
- [Tool Creation](/docs/tool-creation/overview.md)
- [Agent Filesystem](/docs/agent-filesystem/overview.md)
- [Chat Sharing](/docs/chat-sharing/overview.md)
- [Scheduled Triggers](/docs/scheduled-triggers/overview.md)
- [Agent Skills](/docs/agent-skills/overview.md)
- [Subagents](/docs/subagents/overview.md)
- [Workspace Permissions](/docs/workspace-permissions/overview.md)

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