kaos-core 0.1.0a3

Core protocol, runtime, and execution infrastructure for KAOS modules

kaos-core

Part of Kelvin Agentic OS (KAOS) — open agentic infrastructure for legal work, built by 273 Ventures. See the full KAOS package map for the rest of the stack.

kaos-core is the foundational runtime for KAOS modules — an MCP-native type system, runtime container, registries, execution engine, agent primitives, and virtual filesystem.

It is the dependency-light base every other kaos-* package builds on. kaos-core does not run servers, talk to LLMs, or extract documents — companion packages do those things. This package is what makes them all consistent.

To expose kaos-core runtimes over the Model Context Protocol, add the companion package kaos-mcp (ships separately).

Install

uv add kaos-core
# or
pip install kaos-core

kaos-core requires Python 3.13 or newer and has only three runtime dependencies (click, pydantic, pydantic-settings).

Quick start

Define a tool, register it on a runtime, and execute it:

import asyncio

from kaos_core import (
    KaosRuntime,
    ToolAnnotations,
    ToolCapability,
    ToolCategory,
    kaos_tool,
)


@kaos_tool(
    name="kaos-demo-square",
    description="Square an integer",
    category=ToolCategory.DATA,
    capability=ToolCapability.TRANSFORM,
    annotations=ToolAnnotations(readOnlyHint=True, idempotentHint=True),
    auto_register=False,
)
async def square(value: int) -> int:
    return value * value


async def main() -> None:
    runtime = KaosRuntime()
    runtime.tools.register_tool(square)

    tool = runtime.tools.get_tool("kaos-demo-square")
    result = await tool.execute({"value": 7})
    print(result.text)  # "49"


asyncio.run(main())

Inputs are validated against the JSON Schema generated from your type hints — tool.execute({"value": "not-int"}) raises ValidationError before reaching the function body.

Concepts

The package is built around six small, composable primitives.

Concept	What it is
KaosRuntime	Dependency-injection container. Tools, resources, prompts, and namespaces live here. KaosRuntime.default() is fine for scripts and tests; library code should accept a KaosRuntime parameter.
KaosTool	Abstract base for tools. Subclass it directly or use the @kaos_tool decorator. Inputs are type-validated against the JSON Schema derived from your function signature.
KaosContext	Per-execution context with session_id / trace_id for structured logging, plus access to runtime configuration and the artifact store.
ModuleSettings	Typed-settings base class with six-level resolution: explicit overrides → KaosContext._config → KAOS_<MOD>_* env vars → legacy env vars → .env → field defaults. API keys use pydantic.SecretStr so they are redacted in logs.
Artifacts	Three-tier policy for results of varying size. INLINE_THRESHOLD = 16 KB (inline acceptable), SUMMARY_THRESHOLD = 256 KB (summary inline + resource link), larger values move by handle (kaos://artifacts/...). Use ArtifactManifest.to_tool_result() to auto-select the tier.
Virtual filesystem	Flat S3-style namespace (VirtualFileSystem) with memory and disk backends. Range reads, pagination, lazy loading. Directories are emergent; mkdir is a no-op.

CLI

kaos-core ships a kaos-core administrative CLI. Every command supports --json for machine-readable output:

kaos-core tools list                              # registered tools
kaos-core tools search "pdf" --category document  # search by query + facet
kaos-core artifacts list --session my-session     # stored artifacts
kaos-core config show                             # runtime settings (with secrets redacted)
kaos-core vfs ls /artifacts/                      # VFS contents

Compatibility & status

Aspect
Python	3.13, 3.14 (informational matrix entries for 3.14t free-threaded and 3.15-dev)
OS	Linux, macOS, Windows (pure-Python wheel; no native code)
Maturity	Alpha. The public API is documented in kaos_core.__all__ (105 symbols).
Stability policy	Pre-1.0: minor bumps may change behaviour. Every change is documented in CHANGELOG.md. The MCP tool surface and the KAOS_<MOD>_* environment-variable namespace are public API and follow the same policy.
Test coverage	272 tests, 89% line coverage on 2,939 statements.
Type checker	Validated with ty, Astral's Python type checker.

Companion packages

kaos-core is one of the packages in the Kelvin Agentic OS. The broader stack:

Package	Layer	What it does
kaos-core	Core	Foundational runtime, MCP-native types, registries, execution engine, VFS
kaos-content	Core	Typed document AST: Block/Inline, provenance, views
kaos-mcp	Bridge	FastMCP server, kaos management CLI, MCP resource templates
kaos-pdf	Extraction	PDF → AST with provenance
kaos-web	Extraction	Web extraction, browser automation, search, domain intelligence
kaos-office	Extraction	DOCX / PPTX / XLSX readers + writers to AST
kaos-tabular	Extraction	DuckDB-powered SQL analytics
kaos-source	Data	Government + financial data connectors (Federal Register, eCFR, EDGAR, GovInfo, PACER, GLEIF)
kaos-llm-client	LLM	Multi-provider LLM transport
kaos-llm-core	LLM	Typed LLM programming (Signatures, Programs, Optimizers)
kaos-nlp-core	Primitives (Rust)	High-performance NLP primitives
kaos-nlp-transformers	ML	Dense embeddings + retrieval
kaos-graph	Primitives (Rust)	Graph algorithms + RDF/SPARQL
kaos-ml-core	Primitives (Rust)	Classical ML on the document AST
kaos-citations	Legal	Legal citation extraction, resolution, verification
kaos-agents	Agentic	Agent runtime, memory, recipes
kaos-reference	Sample	Reference module for module authors

Packages depend on kaos-core; everything else is opt-in. Mix and match the ones you need.

Development

git clone https://github.com/273v/kaos-core
cd kaos-core
uv sync --group dev

Install pre-commit hooks (recommended — they run the same checks as CI on every commit, scoped to staged files):

uvx pre-commit install
uvx pre-commit run --all-files     # one-time full sweep

Manual QA commands (the same set CI runs):

uv run ruff format --check kaos_core tests
uv run ruff check kaos_core tests
uv run ty check kaos_core tests
uv run pytest -m "not live and not network and not slow"

Build from source

uv build
uv pip install dist/*.whl

Contributing

Issues and pull requests are welcome. By contributing you certify the Developer Certificate of Origin v1.1 — sign every commit with git commit -s. Please open an issue before starting on a non-trivial change so we can align on scope.

Security

For security issues, please do not file a public issue. Report privately via GitHub Private Vulnerability Reporting or email [e-mail]. See SECURITY.md for the full disclosure policy.

License

Apache License 2.0 — see LICENSE and NOTICE.

Copyright 2026 273 Ventures LLC. Built for kelvin.legal.