6 free tools
Every tool.
Free forever.
Instant, private utilities for LLM apps, tool calling and MCP. Everything runs in your browser.
Token & Cost Estimator
Estimate tokens and API cost for a prompt across popular LLMs.
JSON Schema → Tool Definition
Convert a JSON Schema into OpenAI, Anthropic and MCP tool formats.
System Prompt Linter
Catch vague, conflicting or risky instructions in system prompts.
MCP Server Config Generator
Generate mcpServers JSON for Claude Desktop, Cursor and others.
Cron Expression Explainer
Explain cron schedules for agent jobs and preview next runs.
Regex Tester for Agent Outputs
Test regexes that extract structured data from LLM output.
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