pi-telemetry Core: TelemetrySchema Defines Span/Event/Attribute, defineTelemetrySchema Creates TypedSpanStarter, InMemoryTelemetryContext/NOOP_TELEMETRY_CONTEXT Zero-overhead Implementations, Conformance Tests Verify Adapter Correctness, AI/Harness Telemetry Schema Complete Definitions, Attribute Type System, Why Not Use OpenTelemetry Directly.
Zod's 224M weekly downloads (checked August 2026) put it far beyond 'form validation library': API boundaries, environment variables, route search params, LLM tool schemas and structured output all run on the same schemas. The core mechanism is one definition, two payoffs — runtime validation and static types derived from a single source. Zod 4 (on npm July 2025) is faster, slimmer, and easier on tsc.
Different AI engines process web pages in vastly different ways. Some only read the body; others rely on pre-built indexes. JSON-LD and schema markup are not universally effective — body content quality and structure are the only cross-platform foundations that hold.
TypeScript types only exist at compile time — they vanish at runtime. Zod lets you validate external data at runtime while inferring TypeScript types from the same schema. One definition, two jobs done.