ADR-0006 — Sigma.js v3 before any custom renderer

Status: Accepted · 2026-08-18

Context

Graph rendering invites premature engineering. The one-year horizon may need 50k–200k nodes, and wgpu is tempting.

Decision

MAP (M11) renders with Sigma.js v3 (WebGL) over Graphology. A custom renderer is deferred until Sigma is measurably the bottleneck — there is no rendering problem below fifty thousand visible nodes. Layout is computed in the Rust core regardless of renderer (ADR-0001).

Alternatives

• wgpu from the start — rejected: months of renderer work before knowing whether anyone uses MAP; Gate 4 may cut MAP investment entirely.
• SVG/Canvas (d3) — rejected: known ceiling well below 10k nodes at 60fps.

Consequences

10k nodes @ 60 FPS must be verified on Sigma at M11 (it is the documented target, not a measured fact). If the 200k-node future arrives, the renderer swap is contained because the frontend only draws {id, x, y, cluster}.