Compute Assembly

Option C free-text Project entity per 25th-fire (filed 2026-05-19, in-scope for the architectural rewrite per INBOX 26th-fire Amendment C).

Thin-slice precursor to a full Project entity in v1.1: just two optional free-text fields that the workspace surfaces at the top of every assembly form and that propagate to the BoQ header, the PDF cover sheet, and the DXF title block. No DB persistence, no cross-assembly rollup — those land in v1.1.

Envelope: assembly + version + chosen standard + hash cell + export gate.

hash_cell is the 6-char hex from civilquants.core.hash_cell — the cross- reference between this API response, the rendered artefacts, and any email or workspace UI referencing the same parameter set.

export_gate_enabled reflects server-side EXPORT_GATE_<STANDARD>_ENABLED env var per spec §15 invariant — UI never displays "this export would be allowed if X" client-side state. If false, signed URLs are NOT included in the response.

Schema § 1.4 — totals_summary as a typed wrapper around the free-form dict.

Wire shape is a flat object ({"concrete_m3": {...}, "rebar_t": {...}}). We model it as RootModel-equivalent via model_config(extra="allow")

• a single __root__-style entries dict. Pydantic v2 recommends RootModel for free-form roots; using a wrapper class keeps the import surface uniform with the rest of this module.

WorkItem stream behind the BoQ — every measured quantity with its derivation (calculation_steps). Surfaces to the workspace Workings · Audit Trail panel. Standard-agnostic; identical across the four standards because the BoQ rendering is the only standard-aware step. CLAUDE.md pin 10 §15 invariant — every quantity is traceable; "the only margin for error is user input".

Non-fatal geometry advisories (56th-fire T2). Advisory only — never changes a measured quantity; flags geometry that is valid but likely a mistake (e.g. a dependent height left at a stale default after the primary height was raised). Surfaces to the workspace warnings panel. Present on both tiers.

Server-rendered SVG preview of the assembly geometry.

Per G.6.3 / STATUS.md decision 6 (2026-05-19): one source of geometry (DrawEntity list emitted by Assembly.compute), two output paths (this SVG for inline preview, the GET .../dxf endpoint for the real CAD download). The browser displays svg_b64 decoded inline; viewbox drives client zoom/pan controls without re-parsing the SVG.

svg_b64 is base64 of a UTF-8 SVG document with one <g class="cq-layer cq-layer-<name>"> per layer. Styling defaults are inlined so the preview renders without an external stylesheet; front-end CSS may override via the class names.

Signed-URL pointers to rendered Excel + DXF + PDF artefacts. Empty when EXPORT_GATE_<STANDARD>_ENABLED is false (spec §15 invariant: gating is server-side, never client-side).