How It Works

value ──▶ validate ──▶ wire plan ──▶ bytes
          (Standard    (Standard
           Schema)      JSON Schema)

1. Your validator checks the value through Standard Schema, including rules such as .min(1), .email(), and .refine().
2. Standard JSON Schema supplies structure: field names, types, optionality. shorn converts it to a wire plan once and caches it.
3. The plan writes values with no keys and no type tags.
4. Decode runs in reverse, and validates again with your original library.

A payload that decodes structurally but fails a refinement is a DecodeError, never an accepted value.

Two interfaces, two jobs

Interface	Supplies	Used for
Standard Schema	validate(value)	correctness, both directions
Standard JSON Schema	jsonSchema.input() / .output()	structure

Both interfaces are vendor-neutral, so shorn does not need validator-specific code. This also creates its main limitation: shorn cannot encode anything JSON Schema cannot describe. See Date, BigInt, Map, Set.

The wire plan

The JSON Schema becomes a WireShape — a small closed union:

boolean | float64 | int | string | uint
| { array } | { tuple } | { object, rejectUnknown }
| { enum }  | { literal } | { nullable }

Two details drive the choices that matter:

• type: "integer" with minimum >= 0 becomes uint (plain varint); without it, int (ZigZag), which crosses every size boundary at half the value.
• additionalProperties determines how extra fields are handled. false means the validator handles them. If the option is absent, shorn refuses extras during encoding. true or a schema makes the object open, which shorn does not support.

Both jsonSchema.input() and .output() are converted and compared; a schema whose two sides differ needs a bidirectional codec and is refused.

Compiled, then signed

The WireShape becomes a tree of Schema objects — the same objects the m API builds by hand, which is why the two produce identical bytes.

Each node carries a _minWidth: the fewest bytes any value of that shape can occupy. That is what lets an array refuse an impossible element count before allocating. See Hostile Input.

shorn also stores a canonical string signature: the WireShape as JSON without rejectUnknown. fingerprinted() hashes this signature. Removing rejectUnknown lets equivalent Zod and ArkType schemas agree even though they handle extra properties differently. The m API has no signature, so fingerprinted() refuses codecs built with m.

Caching

encode and decode cache the plan in a WeakMap keyed by schema identity, so conversion runs once per schema. See Compilation and Caching.