ADR-0014: No cross-language edges are invented

• Status: Accepted
• Date: 2026-09-20
• Derives from: design.md § What stays honest across the boundary, § The architect's hat (declared edges)
• Constrains: architecture.md § The graph document, § The rule engine
• Implemented by: Wave 2 plan; declared edges in Wave 4

Context

A C# service that calls a Python process over HTTP, or a TypeScript app that calls a .NET API, has no import edge to it. Guessing one would make the graph, and every rule over it, untrustworthy.

Decision

• Extractors record only edges the language's own import or reference mechanism produces. The tool never infers an edge from a URL, a service name or a filename.
• Rules may still span languages, because paths are the shared namespace; such a rule matches nothing until an edge exists, and the liveness default (ADR-0007) says so.
• A predicate a language cannot answer is a validation error (exit 3), not a silent false: areSealed on a Python class fails validation; haveAnyAttributes on it reads decorators. The per-language predicate table lives in rb-rules and is part of the published schema descriptions.
• Wave 4 adds declared cross-service edges (edges.yaml, or read from OpenAPI clients), marked declared on the edge so a reader can tell them from detected ones.

Consequences

• The dependencyKind and dependencyTypes vocabularies are per language, and the coverage tabs record which apply where.
• A mixed-language oracle (dify, OpenMetadata) is one run and one graph with no fabricated edges between halves.

Alternatives considered

• Heuristic cross-language edges. Rejected: precision is the product.