Free vs paid developer tool MCP servers local by default, paid when hosted.

A git MCP server has nothing to charge for: git-mcp-server wraps a binary you already have, against a repo you already own, on hardware you already pay for. The same logic covers the cargo and pare-cargo servers for Rust builds and Unity-MCP driving a Unity Editor on your workstation.

Charging per call for a local stdio wrapper would be charging rent on your own laptop. Nobody does it, and you shouldn't look for it.

Free still has a bill — it's just paid in time. Local servers need installing, updating, and securing; a tool with commit and push access, like pare-git, can do real damage if the agent driving it goes wrong. Build-running servers also consume serious local compute: a clippy pass or Unity compile blocks whatever else the machine is doing.

For teams, multiply that maintenance across every developer machine. That overhead is precisely what creates room for hosted alternatives.

Hosted, priced developer endpoints make sense when the work needs compute, data, or curation you'd rather not maintain: spinning up a clean build environment, running an expensive static analysis, rendering diagrams server-side, or querying a curated rules database. The unit of value is one operation — one build, one analysis report, one render — which maps cleanly to per-call billing.

None of the listings above are claimed to be paid today; the point is structural. Where the tool stops being a thin wrapper and starts being a service, a price becomes reasonable.

x402 lets a hosted dev tool charge from $0.01 per operation without issuing API keys. The agent gets an HTTP 402, pays in USDC on Base, settlement lands in about two seconds, and the operation runs — with an Ed25519-signed receipt for every call and no chargebacks for the operator.

For a coding agent that needs an occasional heavyweight analysis, paying $0.05 once beats a $29/month subscription it would use twice.

Run free local servers for anything touching your own repos, builds, and editors — that's the bulk of this category, from openflowkit-mcp diagramming to the Unity bridges. Pay per call only when the endpoint provides compute or knowledge you don't have locally. Loomal's Developer Tools category puts all 179 live listings, free and priced, in one comparable list.