Tools
apistash provides a growing catalogue of built-in tools accessible over MCP, organised into categories. Each category maps to one section in these docs.
You can also add your own custom tools — connectors to any HTTP API — which appear alongside the built-in tools on the MCP surface.
Categories
Every built-in tool belongs to one category:
| Category | Description |
|---|---|
| Math | Arithmetic, algebra, and mathematical expression evaluation |
| Time | Date and time queries, calculations, and workday/holiday helpers |
| Encoding | Base64 and Base32, cryptographic hashing, JWT signing and verification, and TOTP |
| Utility | General-purpose helpers — UUID generation and validation |
| Conversion | Unit conversion (length, mass, temperature, and more) and file-format conversion (JSON, YAML, TOML, XML) |
| Web | URL parsing, building, encoding, and decoding |
| Validation | Input validation — for example, email addresses |
| Cache | Store and retrieve values across agent sessions (requires an account) |
| Management | Let an agent create and manage your content — prompts, resources, and custom tools (requires an account) |
The built-in catalogue keeps growing — new tool categories are added over time.
Calling tools
Tools are called over MCP. Connect your client to https://api.apistash.io/mcp and ask your AI assistant to use a tool by name — the client issues the tools/call request automatically. There is no REST endpoint for executing tools.
Built-in tools are exposed on MCP with an apistash/ name prefix (for example, apistash/calculator); most clients show a friendly name.
Discovering tools
Your MCP client discovers the tools available to it by calling tools/list. The result is filtered to exactly the tools your credential is allowed to use, so you can ask your assistant "what tools do you have from apistash?" to see the current set.