denselinkage.matching.LangChainMatcher

class denselinkage.matching.LangChainMatcher(*, llm: Any, prompt: str, retry: RetryPolicy | None = None, max_concurrency: int = 1)

Bases: Matcher

LLM matcher (extra: [langchain]).

The llm is injected (any LangChain chat model); model / operational / domain config stay separate. Prompt/output contract: prompt carries ONLY the semantic question and may reference the pair fields ({record_a} / {record_b}). The response structure is framework-owned — the matcher binds structured output and returns typed MatchDecision``s; callers never parse text and the prompt never asks for a format. On exhausted ``retry the matcher yields a MatchError(reason=...) for that pair (aligned by position), never raising into the batch.

match(pairs: Sequence[CandidatePair]) → list[MatchDecision | MatchError]

One outcome per input pair, aligned by position. A pair the matcher cannot decide yields a MatchError (never raises into the batch, so one bad call does not abort the rest).