moca-reader-langchain

A LangChain retriever over MOCA packages, built on the MOCA Reader for Python.

pip install moca-reader-langchain

from moca_reader import LexicalBackend, Library, Search, read_package
from moca_reader_langchain import MocaRetriever

pkg = read_package("support-kb.moca", trust_root="trust-root.json")
library = Library().add(pkg)
search = Search(library, LexicalBackend(library), audiences=["public"])

retriever = MocaRetriever(search=search, limit=3)
for doc in retriever.invoke("How long is the refund window?"):
    print(doc.metadata["moca_node_ref"], doc.metadata["moca_score"])
    print(doc.page_content[:80])

MocaRetriever wraps the Search you build: its backend (lexical, dense, hybrid or your own store), its audiences and its hooks. Every call goes through the Reader’s gate, so content that is out of force, superseded, deprecated or outside your audiences never comes back, and nothing a caller passes can widen that. limit, locale, concepts, scope and include_all are set when you build the retriever.

Each result is a LangChain Document:

Field	Holds
page_content	The text of the node, or of a sidecar chunk
id	The node’s versioned reference and byte span
metadata["moca_citation"]	The whole citation record: package, version and digest, trust signals, evidence
metadata["moca_*"]	The flat fields of the consuming guide (moca_node_ref, moca_package_digest, moca_status, moca_signed, …), for vector stores that need flat metadata
metadata["moca_score"]	The search score

Package text is untrusted input. Put page_content in a prompt as quoted reference material to cite, never as instructions (Reader contract §12). Show users the source (moca_node_ref, the package version) with each answer.

The async path (ainvoke) runs the same search.

Licence

Apache-2.0.