# Agent Toolbox

> Free in-browser tools and a curated directory for AI agent builders. Machine-usable via REST, OpenAPI and MCP.

## Tools
- [Token & Cost Estimator](https://agenttoolbox.net/tools/tokens): Estimate tokens and API cost for a prompt across popular LLMs.
- [JSON Schema → Tool Definition](https://agenttoolbox.net/tools/schema): Convert a JSON Schema into OpenAI, Anthropic and MCP tool formats.
- [System Prompt Linter](https://agenttoolbox.net/tools/lint): Catch vague, conflicting or risky instructions in system prompts.
- [MCP Server Config Generator](https://agenttoolbox.net/tools/mcp): Generate mcpServers JSON for Claude Desktop, Cursor and others.
- [Cron Expression Explainer](https://agenttoolbox.net/tools/cron): Explain cron schedules for agent jobs and preview next runs.
- [Regex Tester for Agent Outputs](https://agenttoolbox.net/tools/regex): Test regexes that extract structured data from LLM output.

## For agents
- [MCP endpoint](https://agenttoolbox.net/api/mcp): Streamable HTTP MCP server
- [OpenAPI](https://agenttoolbox.net/openapi.json)
- [Tools API](https://agenttoolbox.net/api/tools)
- [Directory API](https://agenttoolbox.net/api/directory?q=)

## Plans
- Free: 60 requests/hour per IP, no key.
- [Pro](https://agenttoolbox.net/pricing): $19/month or $190/year. Send your key as the x-api-key header. Keys are shown instantly after checkout.

## Pages
- [Directory](https://agenttoolbox.net/directory)
- [All tools](https://agenttoolbox.net/tools)
- [Sponsor](https://agenttoolbox.net/sponsor)
- [About & contact](https://agenttoolbox.net/about)
- [Refund policy](https://agenttoolbox.net/refunds)