r/AI_Agents: Developer Makes Existing Site Agent-Ready With WebMCP in One Weekend — Finds Zero New Tool-Building Required, Only Wiring

A developer who implemented WebMCP (navigator.modelContext browser API) on an existing site over a weekend found that no new tool-building was required — every existing compute function could be exposed to AI agents without rewrites, because agent-usable tools and human-usable tools share the same shape. The core insight: agent-readiness is a wiring problem, not a construction problem, when the underlying site logic is already well-structured. WebMCP is an emerging browser standard that lets AI agents discover and call a site's native tools without a custom API layer.