nous-lang 4.13.1

NOUS (Νοῦς) — The Living Language for Agentic AI Systems

NOUS (Νοῦς) — The Living Language

The first agentic programming language with formal cost-bound verification.

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Author: Hlias Staurou (Hlia) · Project: Noosphere · GitHub: contrario/nous · Website: nous-lang.org

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What is NOUS?

NOUS is a programming language for agentic AI systems where every program is:

• Verifiable — declare a cost_cap and Z3 proves at compile time that no execution path can ever exceed it.
• Auditable — every verified program emits an ed25519-signed manifest with full provenance (source SHA-256, pricing SHA-256, SMT spec SHA-256, solver name+version, verdict, timestamp).
• Governable — first-class policy { on … signal … action … } declarations are statically lintable (28 rules) and live-simulatable.
• Self-evolving — programs can observe their own execution, evaluate fitness, mutate DNA parameters, and self-heal within constitutional safety bounds.

NOUS transpiles to Python 3.11+ asyncio. The toolchain is a single PyPI package — no Java, no Docker, no LangChain/LlamaIndex/CrewAI dependencies.

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Why v4.13.0 matters

Every other agentic framework lets you set a "max budget" at runtime and abort when it's exceeded — by which point the spend has already happened. NOUS lets you prove before you ship that every reachable execution stays under the cap. The proof is mechanical (Z3), the cost model is auditable (signed pricing TOML with SHA-256), and the artefact (signed manifest) is verifiable by anyone holding your public key — making it directly useful for EU AI Act Annex IV / Article 11(1) technical documentation.

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Install

# Core toolchain
pip install nous-lang

# With SMT cost-bound verification (Z3 + ed25519 signing)
pip install 'nous-lang[smt]'

# With LSP server (VS Code / editor diagnostics)
pip install 'nous-lang[lsp]'

# Everything
pip install 'nous-lang[all]'

Requirements: Python 3.11+. The [smt] extra pulls z3-solver>=4.15.0,<4.17.0 and cryptography>=42,<47.

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60-second quick start

# 1. Initialise a project
mkdir my_world && cd my_world
nous prices init        # writes nous.prices.toml from shipped defaults
nous templates copy gate_alpha   # copies a working .nous program

# 2. Add a cost cap
cat > trading.nous <<'EOF'
world TradingFloor {
    cost_cap: 0.50 USD
    max_ticks: 5
}

soul Trader {
    mind: claude-opus-4-7 @ Tier1
    tokens: input=500 output=200
}

soul Auditor {
    mind: claude-haiku-4-5-20251001 @ Tier2
    tokens: input=200 output=100
}
EOF

# 3. Verify formally
nous verify trading.nous --smt
# → Verdict: PROVEN. Manifest written to trading.manifest.json.

If the cap is too tight, the verifier returns a counterexample with constructive fix suggestions ("raise cap to $0.74" / "reduce max_ticks to 3" / "Trader contributes 68% of worst-case spend").

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Core CLI

nous run file.nous              # compile + execute
nous compile file.nous          # → Python file
nous verify file.nous           # governance lint as build gate
nous verify file.nous --smt     # SMT cost proof + signed manifest
nous emit-smt file.nous         # SMT-LIB 2.6 (re-usable across solvers)

nous prices show                # active layered pricing table + SHA-256
nous prices init                # write nous.prices.toml in cwd
nous prices verify              # cross-check vs shipped defaults
nous prices age                 # how stale is each price entry

nous governance lint file.nous  # 28-rule static analysis
nous governance simulate ...    # what-if policy evaluation

nous templates list             # bundled templates
nous templates copy <name>      # copy a template into cwd
nous lsp                        # start LSP server (stdio)
nous version

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Language at a glance

world ExampleWorld {
    cost_cap: 1.00 USD              # ← formal SMT bound, v4.13.0
    max_ticks: 10                   # ← bound on cycles
    law CostCeiling = $0.10 per cycle
    law MaxLatency = 30s
    law NoLiveTrading = true
}

soul Sentinel {
    mind: claude-opus-4-7 @ Tier1
    tokens: input=1000 output=400   # ← SMT input, v4.13.0
    senses: market_feed, risk_oracle
    speaks: AlertChannel
    remembers: last_signal
}

policy on llm.response signal contains_phrase("absolutely") action log_only weight 0.3

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Architecture

Layer	Implementation
Grammar	Lark LALR (nous.lark), bilingual EN+GR, ~200 rules
AST	Pydantic V2 strict models, 50+ node types
Validator	Constitutional law checker on AST
Pricing	Layered TOML (CLI → project → user → package), SHA-256 audit
SMT emit	Deterministic SMT-LIB 2.6, exact rationals (no floats)
SMT solve	Z3 wrapper + counterexample extraction + fix suggestions
Manifests	ed25519-signed JSON, Sigstore/SLSA-style provenance
CodeGen	AST → Python 3.11+ asyncio
Runtime	asyncio event loop + Noosphere integration
LSP	stdio JSON-RPC, lint diagnostics with source="nous.lint"

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The signed-manifest contract

When nous verify --smt returns PROVEN, it writes a JSON manifest:

{
  "version": "1.0",
  "source_path": "trading.nous",
  "source_sha256": "...",
  "pricing_sha256": "...",
  "smt_sha256": "...",
  "solver": "z3",
  "solver_version": "4.15.2",
  "verdict": "proven",
  "cost_cap": "0.50",
  "currency": "USD",
  "timestamp": "2026-04-28T14:38:33Z",
  "signature": "<base64 ed25519>",
  "public_key": "<base64 ed25519 pubkey>"
}

Anyone with the manifest and the publisher's public key can re-verify offline. Tamper-detection is built in. The verifier signing key lives at ~/.local/share/nous/keys/signing.key (XDG, mode 0600, auto-generated; override with --key-path).

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Documentation

• Cost Verification Guide — end-to-end walkthrough
• SMT Verification Design — soundness contract, Z3 pin rationale
• EU AI Act Compliance — Annex IV / Article 11(1) mapping

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Stats (v4.13.0)

Metric	Value
Tests	264 passing
Regression	54/54 templates byte-identical
Parser throughput	LALR (Lark), 3.3 ms/parse
Grammar rules	~200 (bilingual EN+GR)
AST node types	50+ Pydantic V2 models
New in v4.13.0	cost_cap, tokens, max_ticks, --smt, signed manifests

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License

See LICENSE.

Changelog

See CHANGELOG.md.