0168 — Path literals materialize string params

Decision

Every named segment and terminal wildcard in an endpoint path is parsed once by the contract layer. When params is omitted, Stitchkit materializes a Zod object whose fields are strings and exposes the same shape through handlers, typed clients, OpenAPI, MCP, CLI and the surface manifest. An explicit params schema remains the only way to coerce or further validate values, and it must cover every segment present in the path.

Why

The path already declares the names. Repeating a string-only Zod object at hundreds of endpoints added no information, while type-only inference would have left runtime validation and generated surfaces disagreeing with the TypeScript API. A single canonical parser keeps all projections in phase.

Consequences

• PathParams<P> describes the inferred TypeScript shape.
• A path with segments and no explicit params no longer behaves like an unvalidated raw-parameter endpoint; this is a breaking correction.
• Coercion, UUID checks and other refinements stay explicit.
• Missing segment coverage is rejected when the contract is defined.