Gate 5 — Coherence & Commit
Gate 5 is the final gate. It performs a full coherence check across everything produced by Gates 0–4, synthesises the design into a unified state, and — with your confirmation — commits it permanently to the Purple8 Graph.
What Gate 5 does
- Coherence check — verifies that all five previous gate outputs are consistent with each other:
- Brief (Gate 0) ↔ Programme (Gate 2): every brief requirement has a space that addresses it
- Site (Gate 1) ↔ Option (Gate 3): the selected option is compatible with site constraints
- Programme (Gate 2) ↔ QCRT (Gate 4): no programme items were removed or changed in Gate 4 without re-evaluating the programme
- QCRT (Gate 4) ↔ Option (Gate 3): all critical findings have been resolved
- Produces the Design Summary — a single document summarising the complete concept design
- Generates graph nodes — creates or updates all Space, Zone, Level, Site, Requirement, and Cost Item nodes in the Purple8 Graph
- Awaits your confirmation — the commit is never automatic
The Coherence Report
The coherence check flags any inconsistencies found across the gates:
| Type | Example |
|---|---|
| Unresolved brief gap | "Client requested rooftop amenity space — no space in programme" |
| Programme vs. option mismatch | "Programme has 200m² nursery; selected option has no ground floor provision" |
| Site constraint violation | "Option massing is 8 storeys; site is in a 6-storey max height zone" |
| QCRT open critical | "Travel distance critical finding was marked 'accept' without documented resolution" |
Each flag must be either resolved (make a change) or accepted with documented rationale before committing.
The Design Summary
The Gate 5 Design Summary is a concise record of the concept design:
- Project overview — brief summary, project type, location
- Site — area, key constraints, orientation strategy
- Programme — total GIA, NIA, unit count, mix summary, efficiency ratio
- Design concept — the selected option name and its spatial strategy (2–3 paragraphs)
- Key design decisions — bullet list of the 5–10 most important design choices and their rationale
- QCRT summary — pass/fail counts per lens, open risks
- Next steps — recommended actions for RIBA Stage 2
This summary is saved as a PDF and as a structured node in the project graph. It can be shared directly with clients or included in a Stage 1 report.
Committing to the graph
Once you are satisfied with the coherence check and have reviewed the Design Summary:
- Click Commit Design to Graph
- Add a commit message: "Stage 1 concept design — approved by team 04 Apr 2026"
- Confirm
The commit writes all nodes and relationships to the Purple8 Graph. The design process is marked Complete.
Commits are permanent
A Gate 5 commit cannot be undone — it creates a permanent versioned snapshot. The graph state before the commit is preserved in history, so you can always view what existed before. But the committed design becomes the new project baseline.
After committing
Your project now has a full concept design in the graph. Recommended next steps:
- Refine with the LAD Engine — iterate on specific parts of the layout
- Run Phase 8 Algorithms — daylight, thermal, structural sizing, fire egress
- Upload the result to DocIntel — if you have an IFC export from your BIM tool
- Advance the RIBA Journey — move from Stage 1 to Stage 2
- Share the Design Summary — with the client or the wider project team
The 6-Gate Design Process can be re-triggered at any point on any part of the scheme — for example, to design the ground floor in more detail, or to explore an alternative option for a specific element.