# Typed guarded record join

Build-time release reference. Runtime readiness, deployment, payment settlement and external indexing are not evaluated here. Prices are proposed; this file cannot authorize execution or payment.

WHEN TO USE: Produce actual inner, left or full joined row pairs from two supplied tables using typed scalar JSON Pointer keys. Enforces declared cardinality over both complete inputs before matching; duplicate null-containing keys count for uniqueness even when nullKeys=never-match. Preserves provenance and order, rejects fanout overruns without partial output. No coercion, fuzzy matching, database access or semantic relationship verification.

Release: 0.29.0. Built: 2026-10-06T15:38:00Z.

## Choose for
- Join two tables while retaining source rows and indexes
- Enrich records with a typed lookup and guard duplicate keys
- Build inner left or full joins with explicit many-to-many fanout

## Outside this profile
- Fuzzy or semantic entity matching, coercing scalar keys, or proving a business relationship
- Silently combining colliding columns or truncating a join to fit a cap
- Fetching data, executing caller code, contacting agents, transmitting a payload, or changing remote state
- Verifying semantic truth, source authenticity, identity, permissions, or business relationships

Proposed nominal USD 0.005 per successful call; payer fees excluded. No verified runtime availability.

- [Exact release contract](/reference/services/records-join.json)
- [Input schema](/reference/schemas/records-join.input.json)
- [Output schema](/reference/schemas/records-join.output.json)
- [Fixed example](/reference/examples/records-join.json)
- [Complete HTML reference](/discover/tools/records-join)