---
id: analysis/build-type-edges
name: Implement buildTypeEdges — populate operation graph with type-compatibility edges
status: pending
depends_on:
  - analysis/type-compat
  - graph/construction-operation
scope: narrow
risk: medium
impact: component
level: implementation
---

## Description

Implement `buildTypeEdges()` which iterates over all operation pairs in the graph and adds type-compatibility edges based on `typeCompat()` results. Called internally by `fromSpecs()` and callable manually for incremental construction.

## Acceptance Criteria

- [ ] `buildTypeEdges(graph: FlowGraph<OperationNodeAttrs, OperationEdgeAttrs>): void` — standalone function in `src/analysis/type-compat.ts`
- [ ] For each pair (A, B): call `typeCompat(A.outputSchema, B.inputSchema)`, add edge with result
- [ ] Compatible edges: `edgeType: "typed", compatible: true, detail: "A.output → B.input"`
- [ ] Incompatible edges: `edgeType: "typed", compatible: false, detail describing mismatch, mismatches array`
- [ ] Unknown compatibility (either schema is Unknown): no edge added
- [ ] O(n²) in worst case — documented, acceptable for 10-200 operations
- [ ] Function is callable after incremental `addOperation()` calls
- [ ] Unit tests: known operation specs produce expected edges, incompatible pairs get compatible: false edges, unknown schemas produce no edges

## References

- docs/architecture/analysis.md — buildTypeEdges specification
- docs/architecture/operation-graph.md — edge construction, compatible: false edges rationale

## Notes

> To be filled by implementation agent

## Summary

> To be filled on completion