Tenjin

Tenjin is a tool router for coding agents, built by BackTrackCo and currently in alpha. It installs once via npm and integrates with Claude Code to automatically surface the right external tool — docs lookup, web research, crypto prices, email verification, and more — at the exact moment an agent needs it, without requiring the developer to manage API keys or MCP server configurations.

What It Is

Tenjin sits between a coding agent (currently Claude Code) and a curated catalog of external tools. Rather than forcing developers to sign up for each service, configure MCP servers, and write rules to remind the agent to use them, Tenjin's router watches the agent's prompts, web searches, page fetches, and subagent handoffs. When a curated tool would produce a better result than what the agent was about to do, the router suggests it and the agent calls it. Payments flow automatically through x402, an open HTTP payment standard using USDC on Base, so neither the developer nor the agent needs an account or API key for each provider.

How the Router Works

The Tenjin router hooks into Claude Code at three interception points: the user's prompt, before each web search or page fetch, and when the agent delegates work to a subagent. At each point it consults Jev, a decision model from TypeSafe, to determine whether a tool in the fixed catalog fits the current need. Jev can only select from that fixed list — it cannot write arbitrary calls or instructions. When a tool fits, the agent sees a one-line suggestion with the tool name and price, then calls it through Tenjin's x402 MCP server. When nothing fits, the router stays out of the way entirely.

The Tool Catalog

The catalog is curated and maintained by Tenjin. As of the current alpha, it includes:

• Context7 — current, version-specific library and API docs (free)
• Exa — web research with full page content, not just links
• Firecrawl — reads exact pages as clean text, even when a plain fetch fails
• CoinMarketCap — live crypto price quotes
• Wolfram Alpha — math, unit conversions, and science questions
• Hunter — email address deliverability verification
• Minerva — professional profile lookup from a name or email
• CompanyEnrich — company size, industry, funding, and social data

Twitter/X and Reddit integrations are listed as coming soon. The catalog grows based on user requests submitted via GitHub issues.

Wallet and Payment Model

Tenjin uses x402, an open standard that embeds payments into HTTP. A paid endpoint responds with 402 Payment Required and its price; the client signs a payment for that amount and receives the result. No accounts or API keys are exchanged between parties. tenjin install creates a local wallet holding USDC on Base, encrypted and unlocked through the OS keychain. The private key never leaves the machine and Tenjin never holds or moves user funds. Paying a provider costs no gas. Default spending limits are $0.25 per call and $5 per day, both configurable. Wallets can be funded via Coinbase Onramp (card or Apple Pay) or by sending USDC on Base directly to the wallet address.

Current Status: Alpha

The GitHub repository was created in July 2026 and last pushed in late September 2026, with 29 open issues and active development. The README explicitly labels the project as "in alpha" and notes that Codex support is on the way alongside Claude Code. The license is listed as "Other (NOASSERTION)" on GitHub. The project is open source and installable today via npm i -g tenjin-cli && tenjin install, requiring Node.js 24 or newer and Claude Code.