Speckl

A judgement transport utility for AI-generated specifications. Fulfills NIST SA-11 (human-in-the-loop for automated outputs).

Speckl is a specification language (SpeckDL) with a compiler that produces runnable software — WebAssembly, TypeScript, and provenance artifacts (PROV-O, CycloneDX, SPDX) — from a single source of truth. Write what your system should do. Prove it. Ship it.

The Core Insight

AI generates code at machine speed. Humans own specifications. SpeckDL is the shared space where both can work.

• Human-judgeable — SpeckDL is declarative enough that a person can inspect a spec and say "yes, this captures my intent." The compiled output is opaque; the spec is not.
• AI-writable — SpeckDL's constrained grammar and declarative semantics are tractable for LLMs to produce and reason about. Agents draft. Humans review. Both operate on the same semantic layer.
• Compiled, not generated — The SpeckDL compiler is deterministic. No LLMs in the compilation path. Same spec, same output — always.

What Speckl Does Now

Speckl is a working compiler that turns formal specifications into multiple target representations:

.speckdl spec ──→ Wasm (WebAssembly)     ← runnable, verified state machines
              ├── TypeScript             ← typed, importable classes
              ├── PROV-O (RDF)           ← W3C provenance standard
              ├── CycloneDX SBOM         ← OWASP software bill of materials
              └── SPDX SBOM              ← Linux Foundation SBOM standard

State Machine Compilation (inspired by TLA+)

spec ToggleSwitch {
  state: Status = Off
  enum Status = On | Off

  init: {
    Status = Off
  }

  action FlipSwitch {
    require: true
    if Status == On {
      Status = Off
    } else {
      Status = On
    }
  }
}

This compiles to a runnable WebAssembly module with verified state transitions + guards, and to a type-safe TypeScript class. Both from the same spec.

Provenance Embedded at Compile Time

Every compilation embeds a complete provenance record — PROV-O RDF traces the spec → code derivation, CycloneDX and SPDX SBOMs capture the software supply chain. When an auditor asks "where did this behavior come from?", you query the graph, not Jira.

Real-World Examples

The compiler has been validated against:

Example	Source	Status
ToggleSwitch	SpeckDL tutorial	✅ All 5 artifacts
AccountLedger	Banking ledger with debit/credit	✅ All 5 artifacts
TwoPhaseCommit	TLA+ port	✅ All 5 artifacts
Paxos	TLA+ port	✅ All 5 artifacts
Raft	TLA+ port	✅ All 5 artifacts
TigerBeetleLedger	Naive TigerBeetle core	✅ All 5 artifacts (3 TS type errors in progress)

Getting Started

git clone https://os.scoble.me/forgejo/sscoble/speckl
cd speckl/compiler
npm install

# Compile an example to all 5 targets
node dist/index.js ../examples/ToggleSwitch.speck -o out/switch
ls out/switch/
# ToggleSwitch.wat  ToggleSwitch.ts  ToggleSwitch.prov-o.jsonld
# ToggleSwitch.cyclonedx.json  ToggleSwitch.spdx.json

Key Documents

• Whitepaper v2 — Complete: 8 sections, ~19,000 words. Covers the spec-code gap, SpeckDL language, compiler architecture, embedded provenance, consensus protocols, compliance applications, related work, and roadmap.
• Speckl by Example — Guided tutorial from ToggleSwitch through Raft, with TLA+ comparison table.
• Distribution Strategy — Prioritized roadmap: Show HN → arXiv → blog → consulting pipeline. Conference landscape for 2026-2027.
• Strategy Ladder — Open standard → Consulting → Developer Tool/SaaS → Compliance API.
• SpeckDL Spec — Language definition v0.2.
• State Machine Extension — state/init/action keywords, Set/Map/List types.

Strategy Ladder

Phase	Focus	Status
A — Open Standard	SpeckDL language, compiler, whitepaper, examples	✅ Complete (compiler working, whitepaper done)
B — Consulting	Hands-on engagements with regulated-industry teams	📋 One-pager drafted, awaiting review
C — Developer Tool/SaaS	Self-serve spec validation, provenance browser	🔮 Future
D — Compliance API	Enterprise audit reports, traceability matrices	🔮 Future

Validation Status

• Compiler: 41/41 tests passing (WASM + TypeScript codegen)
• WASM E2E: wabt assemble + instantiate + run verified
• TypeScript: Dual-target compilation — same spec produces both WASM and TS
• TLA+ Trilogy: TwoPhaseCommit, Paxos, Raft all compile (WAT validates through wabt)
• Compiler Self-Spec: speckl-compile.speckdl defines the Speckl compiler in SpeckDL — generates all 5 artifacts (known TypeScript errors tracked in engineering#9)

Known Issues

The rewriteExpr function in the TypeScript generator applies spurious this.state. prefixes to function parameters in guard expressions. Tracked in marcus/engineering#9. Parser also drops precondition:/postcondition: blocks on some action bodies.

Contributing

Speckl is open source under the MIT license. Contributions welcome:

• Language design — refine SpeckDL syntax and semantics
• Compiler development — TypeScript/Node.js, help fix open issues
• Formal methods — verify the compilation pipeline, add TLA+ examples
• Compliance expertise — validate regulatory models (NIST, IEC 62304, DO-178C)
• Documentation — tutorials, guides, case studies

Open an issue or submit a pull request.

License

MIT © Scott Scoble / Greybeard Holdings, LLC

Mirrors

• Primary: https://os.scoble.me/forgejo/sscoble/speckl
• Mirror: https://codeberg.org/sscoble/speckl