chp-core 0.2.2

Capability Host Protocol — local execution evidence for agents, tools, and systems

chp-core

Reference local host for CHP v0.1.

This package is intentionally small:

• register capabilities
• discover declarations
• invoke through a governed envelope
• preserve or generate correlation IDs
• emit append-only SQLite evidence
• replay evidence by correlation ID
• optionally serve discovery, invocation, and replay over local HTTP

Install

pip install chp-core

From this repository:

python -m pip install -e packages/python

Quick Example

from chp_core import LocalCapabilityHost, capability

host = LocalCapabilityHost("example-host")

@capability(
    id="math.add",
    version="1.0.0",
    description="Add two numbers.",
)
def add(a: int, b: int):
    return {"sum": a + b}

host.register(add)

result = host.invoke(
    "math.add",
    {"a": 2, "b": 3},
    correlation_id="demo-correlation",
)

events = host.replay("demo-correlation")

Async handlers are supported. Use await host.ainvoke(...) when already inside an event loop.

By default, invocation payloads are not copied into evidence. Handlers can emit explicit redacted evidence through ctx.emit(...).

Payloads emitted through ctx.emit(...) are redacted by default for common sensitive keys such as token, secret, password, authorization, and api_key.

Adapters

Group related capabilities into an adapter class using BaseAdapter and the @capability decorator. All decorated methods are auto-discovered:

from chp_core import BaseAdapter, capability, LocalCapabilityHost, register_adapter

class MathAdapter(BaseAdapter):
    adapter_id = "math"
    adapter_name = "Math Capabilities"

    @capability(id="math.add", version="1.0.0", description="Add two numbers.")
    async def add(self, ctx, payload):
        return {"sum": payload["a"] + payload["b"]}

    @capability(id="math.mul", version="1.0.0", description="Multiply two numbers.")
    async def multiply(self, ctx, payload):
        return {"product": payload["a"] * payload["b"]}

host = LocalCapabilityHost()
register_adapter(host, MathAdapter())

For standalone functions, use SimpleAdapter:

from chp_core import SimpleAdapter, capability, register_adapter

@capability(id="greet.hello", version="1.0.0", description="Greet someone.")
def hello(name: str):
    return {"message": f"Hello, {name}!"}

register_adapter(host, SimpleAdapter("greet", [hello]))

Shipping an adapter package

Publish your adapter as a standalone package (e.g. chp-linear) and declare it under the chp.adapters entry-point group so hosts can discover it automatically:

# your_adapter/pyproject.toml
[project.entry-points."chp.adapters"]
linear = "chp_linear:LinearAdapter"

Once installed, any host can load all registered adapters:

from chp_core import auto_register_adapters

host = LocalCapabilityHost()
auto_register_adapters(host)  # loads every installed chp.adapters entry point

Or discover them manually:

from chp_core import discover_adapters

for name, adapter_cls in discover_adapters().items():
    print(name, adapter_cls)

chp-core ships a built-in chp-git adapter that exposes Git version-control governance capabilities. It is registered automatically when the package is installed.

HTTP Endpoint

The HTTP helper is transport glue around the same LocalCapabilityHost:

from chp_core import create_http_server

server = create_http_server(host, port=8765)
server.serve_forever()

Routes:

• GET /host
• GET /capabilities
• POST /invoke
• POST /replay
• GET /replay/{correlation_id}

See examples/capability-host-endpoint-demo/.

The package also installs a small CLI:

chp demo endpoint
chp serve-demo --port 8765
chp host
chp invoke demo.search_information --payload '{"query":"CHP vs MCP"}' --correlation-id corr_demo
chp replay corr_demo

Development Evidence Controls

Use chp work to record local engineering work as CHP evidence:

chp work run \
  --intent "Verify the Python test suite." \
  --correlation-id chp-dev-001 \
  --test-run unit \
  -- python -m unittest discover -s packages/python/tests

chp work summary chp-dev-001
chp work replay chp-dev-001
chp work explain chp-dev-001
chp work validate-demo endpoint --correlation-id chp-demo-validation
chp work check-alignment --correlation-id chp-alignment
chp work check-messaging --correlation-id chp-messaging

Tests

cd packages/python
python -m unittest discover -s tests