> For the complete documentation index, see [llms.txt](https://docs.talus.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.talus.network/reference/move/nexus_interface/meta_schema.md).
# nexus\_interface::meta\_schema
* [Struct `PortSchema`](#struct-portschema)
* [Struct `OutputVariantSchema`](#struct-outputvariantschema)
* [Struct `MetaSchema`](#struct-metaschema)
* [Struct `PortInputCommitment`](#struct-portinputcommitment)
* [Enum `ValueKind`](#enum-valuekind)
* [Enum `PortCommitment`](#enum-portcommitment)
* [Constants](#constants)
* [Function `value_kind_object`](#function-value_kind_object)
* [Function `value_kind_data`](#function-value_kind_data)
* [Function `port_schema`](#function-port_schema)
* [Function `output_variant_schema`](#function-output_variant_schema)
* [Function `new`](#function-new)
* [Function `assert_valid_for_tool`](#function-assert_valid_for_tool)
* [Function `conforms_input_cardinality`](#function-conforms_input_cardinality)
* [Function `store_input`](#function-store_input)
* [Function `conforms_input_port`](#function-conforms_input_port)
* [Function `conforms_complete_input`](#function-conforms_complete_input)
* [Function `conforms_raw_output`](#function-conforms_raw_output)
* [Function `canonical_schema_mismatch_failure`](#function-canonical_schema_mismatch_failure)
* [Function `port_commitment_one`](#function-port_commitment_one)
* [Function `port_commitment_many`](#function-port_commitment_many)
* [Function `input_hash`](#function-input_hash)
* [Function `input_hash_for_stored`](#function-input_hash_for_stored)
* [Function `input_ports`](#function-input_ports)
* [Function `port_name`](#function-port_name)
* [Function `port_is_many`](#function-port_is_many)
* [Function `find_input_port`](#function-find_input_port)
* [Function `find_variant_port`](#function-find_variant_port)
* [Function `value_kinds_compatible`](#function-value_kinds_compatible)
* [Function `failure_variant`](#function-failure_variant)
* [Function `failure_port`](#function-failure_port)
### Struct `PortSchema`
One directional Tool port contract.
```move
public struct PortSchema has copy, drop, store
```
Fields
[`port_name`](#nexus_interface_meta_schema_port_name)`: vectoris_many: bool`[`value_kind`](#nexus_interface_meta_schema_value_kind)`:` [`nexus_interface::meta_schema::ValueKind`](#nexus_interface_meta_schema_ValueKind)
#### Struct `OutputVariantSchema`
One mutually exclusive Tool output alternative.
```move
public struct OutputVariantSchema has copy, drop, store
```
Fields
`variant_name: vectorports: vector<`[`nexus_interface::meta_schema::PortSchema`](#nexus_interface_meta_schema_PortSchema)`>`
#### Struct `MetaSchema`
Immutable execution contract registered for one Tool.
```move
public struct MetaSchema has copy, drop, store
```
Fields
[`input_ports`](#nexus_interface_meta_schema_input_ports)`: vector<`[`nexus_interface::meta_schema::PortSchema`](#nexus_interface_meta_schema_PortSchema)`>output_variants: vector<`[`nexus_interface::meta_schema::OutputVariantSchema`](#nexus_interface_meta_schema_OutputVariantSchema)`>`
#### Struct `PortInputCommitment`
Transient serialization-only binding between one immutable port name and its value commitment.
```move
public struct PortInputCommitment has copy, drop, store
```
Fields
[`port_name`](#nexus_interface_meta_schema_port_name)`: vectorcommitment:` [`nexus_interface::meta_schema::PortCommitment`](#nexus_interface_meta_schema_PortCommitment)
#### Enum `ValueKind`
Execution-relevant class of one typed value.
```move
public enum ValueKind has copy, drop, store
```
Variants
Variant `Object`Variant `Data`
#### Enum `PortCommitment`
Transient serialization-only commitment for one immutable-schema port.
```move
public enum PortCommitment has copy, drop, store
```
Variants
Variant `Onekind:` [`nexus_interface::meta_schema::ValueKind`](#nexus_interface_meta_schema_ValueKind)`commitment: vector`Variant `Manykind:` [`nexus_interface::meta_schema::ValueKind`](#nexus_interface_meta_schema_ValueKind)`commitments: vector>`
#### Constants
```move
#[error]
const EInvalidMetaSchema: vector = b"Invalid Tool MetaSchema";
```
```move
#[error]
const EInputSchemaMismatch: vector = b"Tool input schema or canonical data mismatch";
```
```move
#[error]
const EPortCommitmentMismatch: vector = b"Tool input commitment has invalid value kinds";
```
```move
const MAX_IDENTIFIER_BYTES: u64 = 128;
```
```move
const MAX_INPUT_PORTS: u64 = 32;
```
```move
const MAX_OUTPUT_VARIANTS: u64 = 8;
```
```move
const MAX_PORTS_PER_OUTPUT_VARIANT: u64 = 16;
```
```move
const MAX_META_SCHEMA_BYTES: u64 = 65536;
```
```move
const MAX_RAW_OUTPUT_BYTES: u64 = 262144;
```
```move
const INPUT_DOMAIN: vector = vector[110, 101, 120, 117, 115, 46, 100, 105, 114, 101, 99, 116, 46, 118, 51, 46, 114, 101, 115, 111, 108, 118, 101, 100, 45, 105, 110, 112, 117, 116];
```
```move
const FAILURE_VARIANT: vector = vector[95, 101, 114, 114, 95, 101, 118, 97, 108];
```
```move
const FAILURE_PORT: vector = vector[114, 101, 97, 115, 111, 110];
```
```move
const SCHEMA_MISMATCH_REASON: vector = vector[84, 111, 111, 108, 32, 111, 117, 116, 112, 117, 116, 32, 115, 99, 104, 101, 109, 97, 32, 109, 105, 115, 109, 97, 116, 99, 104];
```
#### Function `value_kind_object`
```move
public fun value_kind_object(): nexus_interface::meta_schema::ValueKind
```
#### Function `value_kind_data`
```move
public fun value_kind_data(): nexus_interface::meta_schema::ValueKind
```
#### Function `port_schema`
```move
public fun port_schema(port_name: vector, is_many: bool, value_kind: nexus_interface::meta_schema::ValueKind): nexus_interface::meta_schema::PortSchema
```
#### Function `output_variant_schema`
```move
public fun output_variant_schema(variant_name: vector, ports: vector): nexus_interface::meta_schema::OutputVariantSchema
```
#### Function `new`
```move
public fun new(input_ports: vector, output_variants: vector): nexus_interface::meta_schema::MetaSchema
```
#### Function `assert_valid_for_tool`
```move
public fun assert_valid_for_tool(self: &nexus_interface::meta_schema::MetaSchema, is_offchain: bool)
```
#### Function `conforms_input_cardinality`
Checks whether the One/Many variant matches the schema cardinality.
```move
public fun conforms_input_cardinality(schema: &nexus_interface::meta_schema::PortSchema, value: &nexus_primitives::data::NexusData): bool
```
#### Function `store_input`
Validates untrusted typed values against one port schema and constructs canonical data.
```move
public fun store_input(schema: &nexus_interface::meta_schema::PortSchema, values: vector): nexus_primitives::data::NexusData
```
#### Function `conforms_input_port`
Checks canonical cardinality and semantic kind directly from stored values.
```move
public fun conforms_input_port(schema: &nexus_interface::meta_schema::PortSchema, value: &nexus_primitives::data::NexusData): bool
```
#### Function `conforms_complete_input`
Checks complete canonical inputs in immutable schema order.
```move
public fun conforms_complete_input(self: &nexus_interface::meta_schema::MetaSchema, values: &vector): bool
```
#### Function `conforms_raw_output`
Checks an exact ordered canonical output envelope.
```move
public fun conforms_raw_output(self: &nexus_interface::meta_schema::MetaSchema, output: &nexus_primitives::tagged_output::TaggedOutput): bool
```
#### Function `canonical_schema_mismatch_failure`
Builds the canonical schema-mismatch output through the typed active builder.
```move
public fun canonical_schema_mismatch_failure(): nexus_primitives::tagged_output::TaggedOutput
```
#### Function `port_commitment_one`
```move
public fun port_commitment_one(value: &nexus_primitives::data::NexusValue): nexus_interface::meta_schema::PortCommitment
```
#### Function `port_commitment_many`
```move
public fun port_commitment_many(values: &vector): nexus_interface::meta_schema::PortCommitment
```
#### Function `input_hash`
Hashes canonical schema-ordered name/commitment pairs shared by Nexus and on-chain Tools.
```move
public fun input_hash(port_names: vector>, commitments: vector): vector
```
#### Function `input_hash_for_stored`
Validates complete persisted canonical inputs and derives the shared input hash.
```move
public fun input_hash_for_stored(self: &nexus_interface::meta_schema::MetaSchema, values: &vector): vector
```
#### Function `input_ports`
```move
public fun input_ports(self: &nexus_interface::meta_schema::MetaSchema): &vector
```
#### Function `port_name`
```move
public fun port_name(self: &nexus_interface::meta_schema::PortSchema): &vector
```
#### Function `port_is_many`
```move
public fun port_is_many(self: &nexus_interface::meta_schema::PortSchema): bool
```
#### Function `find_input_port`
```move
public fun find_input_port(self: &nexus_interface::meta_schema::MetaSchema, name: &vector): std::option::Option
```
#### Function `find_variant_port`
```move
public fun find_variant_port(self: &nexus_interface::meta_schema::MetaSchema, variant_name: &vector, port_name: &vector): std::option::Option
```
#### Function `value_kinds_compatible`
```move
public fun value_kinds_compatible(from: &nexus_interface::meta_schema::PortSchema, to: &nexus_interface::meta_schema::PortSchema): bool
```
#### Function `failure_variant`
```move
public fun failure_variant(): vector
```
#### Function `failure_port`
```move
public fun failure_port(): vector
```
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