Kernel Package v0 Schema

Updated: 2026-06-17.

kaspascript kernel package <contract.ks> emits one JSON object that combines the compiled txscript artifact with the KaspaScript kernel package.

The package is meant for wallets, indexers, SDKs, and review tools. It is not a replacement for node, wallet, or consensus validation.

Generate A Package

cargo run -p kaspascript-cli -- kernel package tests/contracts/escrow.ks \
  --target verified-tn12 \
  --output /tmp/escrow.kernel.json \
  --compute-grams 1000 \
  --tx-bytes 400

Without --output, the CLI writes beside the source with a .kernel.json extension.

Root Object

{
  "schema_version": "kaspascript.kernel.package.v0",
  "package_target": "verified-tn12",
  "source_snapshots": [],
  "artifact": {},
  "bytecode_hex": "...",
  "bytecode_asm": "...",
  "kernel": {},
  "fee_estimate": {}
}

Field	Type	Notes
`schema_version`	string	Current value: `kaspascript.kernel.package.v0`.
`package_target`	string	Package target selected by the CLI.
`source_snapshots`	array	Pinned upstream source snapshots used by the package evidence set.
`artifact`	object	Compiler artifact summary.
`bytecode_hex`	string	Hex-encoded compiled txscript bytes.
`bytecode_asm`	string	Human-readable txscript assembly.
`kernel`	object	Wallet, indexer, readiness, blueprint, and fee policy metadata.
`fee_estimate`	object	Fee estimate using the selected package assumptions.

Package targets:

verified-tn12
tn10-toccata
toccata-preview
future-mainnet

Source Snapshots

{
  "upstream_repo": "https://github.com/kaspanet/rusty-kaspa",
  "tag": "v2.0.1",
  "commit": "cfafeb4c093fa37a303f1b9f19c58f986b870ce3",
  "audit_date": "2026-06-17"
}

The v0 package pins Rusty Kaspa snapshots for v2.0.1, v2.0.0, v1.3.0-toc.5, and tn10-toc3. v2.0.1 is the current Toccata upgrade release at this audit date. v2.0.0 remains the baseline activation release, with activation scheduled for DAA score 474,165,565, roughly June 30, 2026 at 16:15 UTC; both releases are still treated as pre-activation evidence at this audit date. Consumers should treat snapshots as evidence metadata, not as a replacement for node validation.

Artifact Summary

{
  "backend": "kaspa-txscript",
  "target": "verified-tn12",
  "compiler_version": "0.1.0",
  "bytecode_bytes": 76,
  "finality_depth": 10,
  "kip_requirements": [10],
  "contracts": ["Escrow"],
  "spends": ["Escrow.release", "Escrow.refund"]
}

Field	Type	Notes
`backend`	string	Current value: `kaspa-txscript`.
`target`	string	Compiler target label such as `verified-tn12`.
`compiler_version`	string	Compiler crate version.
`bytecode_bytes`	number	Compiled bytecode length in bytes.
`finality_depth`	number or null	Contract finality depth if declared.
`kip_requirements`	array	KIPs required by the compiled bytecode or guarded features.
`contracts`	array	Contract names found in the artifact.
`spends`	array	Fully qualified spend path names.

Kernel Object

{
  "schema_version": "kaspascript.kernel.package.v0",
  "blueprint": {},
  "readiness": {},
  "capabilities": {},
  "wallet_previews": [],
  "indexer_schema": {},
  "fee_policy": {
    "sompi_per_unit": 100
  },
  "application": {}
}

Field	Type	Notes
`schema_version`	string	Current value: `kaspascript.kernel.package.v0`.
`blueprint`	object	Contract state-machine model.
`readiness`	object	Evidence-based readiness report.
`capabilities`	object	Machine-readable contract capability profile for wallets, SDKs, indexers, and agents.
`wallet_previews`	array	Wallet-facing transition previews.
`indexer_schema`	object	Suggested indexer tables and columns.
`fee_policy.sompi_per_unit`	number	Toccata pre-activation minimum fee unit.
`application`	object	Canonical `kaspascript.application.v0` model shared with the compiler artifact and SDK.

The application model is defined in KASPASCRIPT_PROGRAM_MODEL.md and has a machine-readable schema at schemas/kaspascript.application.v0.schema.json. The complete compiled package schema is schemas/kaspascript.kernel.package.v0.schema.json.

Blueprint

{
  "name": "Escrow",
  "network": "Tn12",
  "state": [],
  "transitions": [],
  "evidence": []
}

Field	Type	Notes
`name`	string	Contract or package name.
`network`	enum string	`Mainnet`, `Tn10`, `Tn12`, `Simnet`, `Devnet`, or `Unknown`.
`state`	array	State fields derived from contract params or blueprint state.
`transitions`	array	Spend/state transition definitions.
`evidence`	array	Source evidence attached to package claims.

State field:

{
  "name": "buyer",
  "ty": "PublicKey",
  "description": "compiled parameter from contract Escrow"
}

Current ty values are PublicKey, Signature, Sompi, DaaScore, BlockHeight, CovenantId, Hash, Bool, U64, and Bytes.

Transition:

{
  "name": "release",
  "kind": "Spend",
  "consumes": ["Escrow compiled locking state"],
  "creates": ["transaction outputs selected by the spend path"],
  "signers": ["sig_a", "sig_b"],
  "requirements": [],
  "proof": {
    "verifier": "None",
    "public_inputs": [],
    "payload_hint": "no proof payload"
  },
  "wallet_warnings": []
}

Compiled transitions also carry an internal link to their canonical transition model. The link is used to build wallet previews and capability summaries but is not duplicated inside serialized blueprint transitions.

Current kind values are Deposit, Spend, Timeout, Recover, Close, or {"Custom": "label"}.

Requirement:

{
  "feature": "BaseScript",
  "minimum_evidence": "BranchCode",
  "reason": "compiled artifact emitted verified Kaspa txscript bytecode"
}

Current feature values are BaseScript, TransactionIntrospection, CovenantIds, SequencingCommitments, ZkVerification, FeePolicy, WalletPreview, and IndexerLineage.

Current evidence levels are Unknown, ResearchSignal, DocsSignal, BranchCode, MergedKip, MergedCode, TestnetActivation, MainnetPreActivation, and MainnetActivation.

Evidence:

{
  "label": "KaspaScript compiled artifact",
  "url": "tests/contracts/escrow.ks",
  "audit_date": "2026-06-17T13:00:00Z",
  "network": "Tn12",
  "level": "BranchCode",
  "features": ["BaseScript", "WalletPreview", "IndexerLineage"],
  "note": "local compiler artifact verified before kernel package emission"
}

Wallet Previews

{
  "contract": "Escrow",
  "transition": "release",
  "network": "Tn12",
  "classification": "CovenantStateTransition",
  "consumes": ["Escrow compiled locking state"],
  "creates": ["transaction outputs selected by the spend path"],
  "signers": ["sig_a", "sig_b"],
  "proof": {
    "verifier": "None",
    "public_inputs": [],
    "payload_hint": "no proof payload"
  },
  "warnings": []
}

Compiled wallet previews include semantics, which is the selected canonical transition model. It exposes signing requirements, classified source constraints, referenced input/output indexes, exact-count limitations, monetary responsibility, output bindings, and continuation posture.

Current classification values are OrdinaryPayment, CovenantStateTransition, and ProofBearingTransition.

Current proof verifier values are None, Groth16, Risc0Succinct, or {"External": "label"}.

Wallets should treat warnings as sign-time copy and should not render CovenantStateTransition as a plain payment.

Indexer Schema

{
  "contract": "Escrow",
  "network": "Tn12",
  "tables": [
    {
      "name": "covenant_lineage",
      "columns": [
        {
          "name": "covenant_id",
          "ty": "bytes32",
          "required": true
        }
      ]
    }
  ]
}

Column ty is a descriptive storage type. The current package emits covenant lineage, covenant transition, and wallet preview audit table suggestions.

Readiness Report

{
  "contract": "Escrow",
  "network": "Tn12",
  "level": "verified",
  "ready": true,
  "blockers": [],
  "features": []
}

Readiness levels:

verified: every transition requirement is satisfied for a non-preview target network.
preview: evidence is sufficient for analysis, but the package target is intentionally preview-scoped.
blocked: at least one blocker prevents the package from being treated as ready.

Feature readiness line:

{
  "transition": "release",
  "feature": "BaseScript",
  "required": "BranchCode",
  "best": "BranchCode",
  "level": "verified",
  "satisfied": true,
  "source_label": "KaspaScript compiled artifact"
}

ready is true only when every transition requirement is satisfied by the available evidence for the package network. Mainnet packages remain blocked until MainnetActivation evidence exists for required mainnet features.

Capabilities

{
  "schema_version": "kaspascript.kernel.package.v0",
  "contract": "Escrow",
  "network": "Tn12",
  "readiness_level": "verified",
  "ready": true,
  "execution_model": "kaspa-utxo-state-machine",
  "scope": [
    "compile-to-kaspa-txscript",
    "wallet-preview",
    "indexer-lineage",
    "fee-estimate",
    "readiness-report"
  ],
  "features": [],
  "transition_profiles": [],
  "wallet_requirements": [],
  "indexer_requirements": [],
  "policy_limits": []
}

The capability profile is a compact contract digest for app tooling. It does not add consensus behavior. It describes what the package can support and what external systems must still verify or render.

Field	Type	Notes
`execution_model`	string	Current value: `kaspa-utxo-state-machine`.
`scope`	array	Package surfaces currently emitted by the kernel.
`features`	array	KaspaScript/Kaspa features required by the transition set with readiness and evidence.
`transition_profiles`	array	Per-spend digest with kind, signers, proof verifier, required features, and wallet effect.
`wallet_requirements`	array	Sign-time wallet duties derived from the package.
`indexer_requirements`	array	Indexer duties derived from emitted schema tables.
`policy_limits`	array	Hard boundaries, including the fact that packages do not replace node or consensus validation.

Feature capability:

{
  "feature": "TransactionIntrospection",
  "level": "verified",
  "best_evidence": "MergedCode",
  "description": "spend logic can inspect selected transaction inputs or outputs"
}

Transition profile:

{
  "transition": "release",
  "kind": "Spend",
  "signer_count": 2,
  "signers": ["sig_a", "sig_b"],
  "proof_verifier": "None",
  "required_features": [
    "BaseScript",
    "WalletPreview",
    "IndexerLineage",
    "TransactionIntrospection"
  ],
  "wallet_effect": "Consumes Escrow compiled locking state and creates transaction outputs selected by the spend path."
}

Compiled transition profiles additionally include:

constraint_kinds
transaction_shape
monetary_policy
continuation

Fee Estimate

{
  "policy": "toccata-rpc-minimum-standard-fee",
  "source": "https://github.com/kaspanet/rusty-kaspa/blob/v2.0.1/docs/toccata-guide.md",
  "compute_grams": 1000,
  "transaction_bytes": 400,
  "minimum_standard_fee_sompi": 100000,
  "assumption": "caller-provided fee estimate inputs"
}

The current formula is:

100 sompi * max(compute_grams, 2 * transaction_bytes)

When --tx-bytes is omitted, the CLI uses compiled bytecode length as a lower bound for transaction_bytes. When --compute-grams is omitted, it uses 0.

Compatibility Notes

Enum strings are serialized as Rust variant names, for example Tn12 and BaseScript.
Readiness levels are serialized as lowercase v0 labels: verified, preview, and blocked.
The schema is additive while the CLI is pre-1.0. Consumers should ignore unknown fields and require the root fields listed above.
Machine-readable JSON Schemas are published for the application model, compiled kernel package, and stable CLI reports.

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Kernel Package v0 Schema

Generate A Package

Root Object

Source Snapshots

Artifact Summary

Kernel Object

Blueprint

Wallet Previews

Indexer Schema

Readiness Report

Capabilities

Fee Estimate

Compatibility Notes

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Kernel Package v0 Schema

Generate A Package

Root Object

Source Snapshots

Artifact Summary

Kernel Object

Blueprint

Wallet Previews

Indexer Schema

Readiness Report

Capabilities

Fee Estimate

Compatibility Notes