# Product blueprint Jacobian is an MCP server for two atomic mathematical verbs: find an operation and run one operation. It is not a workflow engine, workspace, artifact store, or mathematical project manager. The server owns typed operation contracts, strict request validation, resource bounds, immutable discovery, and the final MCP projection. The caller owns decomposition, sequencing, persistence of any values it needs, and stopping. For an ordinary call, Jacobian selects one immutable declaration, parses its Pydantic request once, calls the domain-owned function, and returns that function's concrete typed result. The function may use a maintained library such as SymPy, FLINT, NetworkX, or Z3 privately; Jacobian owns the public mathematical semantics, not a second provider/runtime abstraction around that library. Built-in operations are explicit immutable declarations. Ordinary results are small bounded values returned directly. No operation can silently publish a durable artifact or retain caller state. A direct mathematical predicate—such as checking a SAT assignment—owns its request and result alongside the mathematics. The kernel has no generic checker registry, receipt, or record service.