ADR-033: Ruvocal WASM-MCP Integration from RuVector Upstream

Status: Proposed Date: 2026-05-01 Author: Ruflo Team Deciders: Engineering Related: ADR-002-WASM-CORE-PACKAGE, ADR-029-HUGGINGFACE-CHAT-UI-CLOUD-RUN, ADR-030-MCP-TOOL-GAP-ANALYSIS, ADR-032-RVF-PRIVATE-MCP-TUNNEL

Context

The local copy of the Ruvocal chat UI at ruflo/src/ruvocal/ is a snapshot fork of the SvelteKit-based HuggingFace chat-ui (v0.20.0). The canonical upstream lives at ruvnet/RuVector/ui/ruvocal and has diverged with substantial new functionality, primarily an in-browser WASM MCP server powered by rvagent-wasm.

A directory-level diff between upstream and local shows:

Net-new in upstream (absent locally):

• src/lib/wasm/ — WASM loader, types, IndexedDB persistence, capability tests (84 KB)
• src/lib/components/wasm/GalleryPanel.svelte — UI for browsing/loading WASM templates
• src/lib/components/FoundationBackground.svelte
• src/lib/stores/wasmMcp.ts — Svelte store wrapping WASM MCP server lifecycle
• src/lib/constants/rvagentPresets.ts — preset templates
• src/lib/server/textGeneration/mcp/wasmTools.test.ts
• static/wasm/rvagent_wasm.js + rvagent_wasm_bg.wasm — compiled WASM bundle (~588 KB)
• config/branding.env.example

Modified upstream (incompatible drift in local):

• Chat components: ChatInput, ChatMessage, ChatWindow, ChatIntroduction, BlockWrapper, TaskGroup, ToolUpdate, FileDropzone
• MCP UI: MCPServerManager, AddServerForm, ServerCard
• Servers: lib/server/mcp/clientPool.ts, httpClient.ts, lib/server/router/toolsRoute.ts, lib/server/textGeneration/index.ts, runMcpFlow.ts, toolInvocation.ts, types.ts, utils/toolPrompt.ts
• Stores/utils: mcpServers.ts, settings.ts, Settings.ts, Tool.ts, messageUpdates.ts, switchTheme.ts
• Routes: +layout.svelte, models/+page.svelte, settings layout/model pages, conversation/[id]/+page.svelte & +server.ts, api/mcp/health/+server.ts, api/mcp/servers/+server.ts, api/v2/user/settings/+server.ts
• Visual/branding: app.html, styles/main.css, static/chatui/{favicon,icon,logo}.svg, static/chatui/manifest.json
• Misc: Modal.svelte, NavMenu.svelte, RuFloUniverse.svelte, Switch.svelte, WelcomeModal.svelte, Logo.svelte, mcpExamples.ts, .gitignore, rvf.manifest.json

Local-only (must preserve):

• mcp-bridge/index.js — local MCP bridge implementation (absent in upstream)
• src/routes/api/v2/debug/ — debug routes used by ruflo
• stub/@reflink/reflink/index.js — reflink stub
• .env — populated local environment
• package-lock.json — local lockfile
• All ruflo-specific docs/CLAUDE.md guidance

package.json is identical between local and upstream — no dependency changes required.

Decision

We will pull the upstream improvements into ruflo/src/ruvocal/ on a dedicated feature branch (feat/ruvocal-wasm-mcp-integration) using a directory-level overlay strategy rather than a Git merge, because the local snapshot has no shared history with the upstream repository.

The integration is staged in three commits to keep the diff reviewable:

1. NEW files — copy WASM core, components, stores, constants, static assets, and config example. Pure additions; cannot break existing behavior.
2. MODIFIED files — overwrite divergent files with upstream versions, then re-apply local-only customizations:
   • Restore src/routes/api/v2/debug/ after upstream overlay (upstream lacks it).
   • Restore mcp-bridge/index.js after overlay.
   • Restore stub/@reflink/reflink/index.js.
   • Keep local .env and package-lock.json untouched.
3. Verification — npm install, npm run check, npm run build, then local docker compose + ruflo-browser smoke test.

The package.json overlay is safe because it is byte-identical.

What we are explicitly NOT doing

• No Git submodule or subtree linkage to RuVector — keeps the snapshot model intact.
• No changes to ruflo/src/chat-ui/ (the thin HF base-image wrapper) in this ADR.
• No Cloud Run deployment in this change — that is tracked separately under ADR-011 / ADR-029.
• No upstream contribution back to RuVector at this time.

Consequences

Positive:

• Brings in-browser WASM MCP capability — chat UI gains local tool execution without a backend bridge for the supported tool set.
• Aligns local with canonical upstream, narrowing the divergence we have to maintain by hand.
• New GalleryPanel UX for browsing rvagent templates.
• Tests added (wasmTools.test.ts, wasm-capabilities.test.ts) raise the coverage floor.

Negative / risks:

• Increases bundle size by ~588 KB (the WASM artifact). Loaded lazily via browser-gated dynamic import, so initial paint is unaffected.
• Local-only files (mcp-bridge/index.js, routes/api/v2/debug/) must be re-applied after each upstream sync; this ADR documents that requirement so future syncs don't drop them.
• Modified server-side files (clientPool, httpClient, toolsRoute, runMcpFlow, etc.) may interact with the local mcp-bridge differently than upstream's. Smoke test before merge.
• Changes to Settings.ts / Tool.ts types could ripple into ruflo packages that import from src/ruvocal. Mitigation: run npm run check before merging.

Rollback: revert the feature branch; no data migrations, no external service changes.

Verification

Acceptance criteria for merging the branch:

• npm install succeeds.
• npm run check passes (svelte-check, no new TS errors).
• npm run build produces a working bundle.
• npm run test — wasmTools.test.ts and wasm-capabilities.test.ts pass.
• docker compose up -d brings up MongoDB; npm run dev serves at http://localhost:5173.
• ruflo-browser smoke test: load the home page, open the gallery panel, send a message through a non-WASM model, confirm no console errors.
• Local-only files still present after overlay: mcp-bridge/index.js, routes/api/v2/debug/, stub/@reflink/reflink/index.js, .env, package-lock.json.

Deployment

Cloud Run deployment is out of scope for this PR but the path is staged in ruflo/src/ruvocal/cloudbuild.yaml. Two infrastructure prerequisites must be satisfied before the first deploy:

1. MongoDB endpoint — HF chat-ui requires a Mongo server. Cloud Run cannot run Mongo natively. Two options:
   • MongoDB Atlas free tier (M0): create a cluster, get the connection string, store as Secret Manager secret ruvocal-mongodb-url.
   • Cloud Run multi-container (sidecar): deploy a mongo:8 sidecar in the same revision; main container connects to localhost:27017. Requires --container flags on gcloud run deploy.
2. AI provider secrets — already exist in ruv-dev Secret Manager per ADR-029: openai-api-key, google-api-key, openrouter-api-key.

Once both are in place:

cd ruflo/src/ruvocal
gcloud builds submit --config=cloudbuild.yaml --project=ruv-dev --region=us-central1

Validation after deploy: npx agent-browser open <run-url> then check console for [WASM MCP] Server initialized successfully · 18 tools.

The thin ruflo/src/chat-ui/Dockerfile wrapper (FROM ghcr.io/huggingface/chat-ui-db:latest) is unsuitable for deploying this integration — it can only patch the upstream HF base image with a few static files; it cannot include compiled WASM source. The full ruvocal Dockerfile build is required.

Deployment Outcome (2026-05-01)

The Cloud Run pipeline is working end-to-end with the following validations:

Custom Domain (2026-05-01)

• ruvocal.ruv.io mapped via gcloud beta run domain-mappings create
• Cloudflare DNS: CNAME ruvocal → ghs.googlehosted.com., proxied:false (gray cloud) so Google can issue and renew the managed cert directly
• Cert provisioning is asynchronous; allow 15–30 min after DNS resolves before HTTPS works on the custom domain. The *.run.app URL is always available immediately

Provider Configuration (2026-05-01)

The deployed instance uses Gemini 2.5 Flash as default via Google's OpenAI-compatible endpoint:

OPENAI_BASE_URL=https://generativelanguage.googleapis.com/v1beta/openai/
OPENAI_API_KEY=<from GOOGLE_AI_API_KEY secret>
TASK_MODEL=gemini-2.5-flash

Earlier attempts with https://router.huggingface.co/v1 returned 401 "Invalid username or password" because the available huggingface-token secret doesn't auth against the user-facing router endpoint, and the OpenRouter API key was incorrectly mapped against the HF base URL. Google's OpenAI-compatible endpoint accepts GOOGLE_AI_API_KEY directly and exposes 56 Gemini variants.

Known Issue (RESOLVED 2026-05-01)

The homepage / returns HTTP 500 in production due to the /api/v2/models and /api/v2/models/refresh routes returning the SvelteKit "Page not found" page wrapped in a 500 status.

Root cause (found after extensive investigation): .gitignore line 16 was models/* (unanchored). With no .gcloudignore present, gcloud builds submit falls back to .gitignore for upload filtering — that pattern matched every models/ directory in the tree, stripping src/routes/api/v2/models/* and src/routes/models/* from the source tarball before Docker even saw it. SvelteKit production builds inside the container therefore had no /api/v2/models route registered, so requests returned 404 which got wrapped as 500 by the layout chain.

Fix: ruflo/src/ruvocal/.gcloudignore (commit e3b74f606). All /api/v2/* routes now serve correctly. Verified via gsutil cp of the build's source tarball that all +server.ts files for the models subtree are present after the fix.

Mid-Iteration Updates (2026-05-01)

This section consolidates changes that landed after the initial PR (#1687) merged:

Provider switch: OpenRouter / Claude Sonnet 4.6 default

Gemini 2.5 Flash via the OpenAI-compat endpoint returned Error: 400 status code (no body) on the follow-up call after a tool result (the chat-ui sends the tool message back to the model in the next turn; Gemini's compat layer rejected the structure intermittently). The result was the user-visible "Sorry, something went wrong" after a tool fired.

Switched the deployed default to Claude Sonnet 4.6 via OpenRouter with OPENAI_BASE_URL=https://openrouter.ai/api/v1 and OPENAI_API_KEY mapped from the OPENROUTER_API_KEY Secret Manager secret. Models exposed: Claude Sonnet 4.6 (default), Claude Opus 4.7, Claude Haiku 4.5, Gemini 2.5 Pro, Gemini 2.5 Flash, GPT-4o.

The system prompt explicitly instructs the model to emit multiple tool_calls in a single response when the request implies multiple independent steps. Server logs confirmed toolMsgCount: 4 and toolMsgCount: 6 — multiple tools dispatched in parallel via Promise.all in src/lib/server/textGeneration/mcp/toolInvocation.ts.

MCP Bridge service (mcp-bridge on Cloud Run)

Deployed in parallel with ruvocal to expose 207 tools across 5 server groups (Core / Intelligence / Agents / Memory / DevTools). Pinned --min-instances=1 --max-instances=1 so backends stay warm — Cloud Run was previously routing requests to cold instances that had not yet finished spawning npx ruflo mcp start and npx ruvector mcp start. Bumped the bridge's MCP initialize RPC timeout from 30s → 120s to handle cold-start boot times.

Web Worker for WASM MCP (opt-in)

Added src/lib/wasm/wasm.worker.ts and src/lib/wasm/workerClient.ts. When the user opts in via ?worker=1 URL param or localStorage.setItem("ruflo:wasm-worker", "true"), callMcp routes through a worker-owned mock WasmMcpServer instead of the in-process module. Default behavior (in-process path) is unchanged.

The worker is self-contained — it does not import $app/environment (which is unresolvable in worker context) and ships a minimal read_file / write_file / list_files MCP surface as a placeholder until the real rvagent_wasm.js bundle is wired in.

Custom domains

Mapped via Cloudflare DNS (CNAME unproxied so Google manages the cert):

• flo.ruv.io (primary)
• ruflo.ruv.io
• ruvocal.ruv.io

UX additions

• Help icon in sidebar opens "RuFlo Capabilities" modal (src/lib/components/RufloHelpModal.svelte) with all 6 tool groups, quick-start, tips, and resource links.
• 8 RuFlo-themed example prompts on the welcome screen (src/lib/constants/{mcpExamples,routerExamples}.ts) replacing HF defaults.
• PUBLIC_APP_NAME=RuFlo brands the title bar, sidebar, welcome modal, and PWA manifest.

Bug fixes

• mcp-bridge returns a structured hint object instead of opaque 400 when search is called with an empty query (Error: search requires a non-empty query string).
• cloudbuild.yaml deploy step strips its --set-env-vars / --set-secrets flags so subsequent rebuilds preserve manually configured env (DOTENV_LOCAL with MODELS, OPENAI_BASE_URL, etc.). Initial env config is now set out-of-band via gcloud run services update.
• DOCKER_BUILDKIT=1 env on the cloudbuild docker step (Dockerfile uses COPY --link BuildKit syntax).

Follow-Up Work (tracked separately in issue #1689)

References

• Upstream source: https://github.com/ruvnet/ruvector → ui/ruvocal/
• Local target: ruflo/src/ruvocal/
• Branch: feat/ruvocal-wasm-mcp-integration (squash-merged to main)
• PR: https://github.com/ruvnet/ruflo/pull/1687
• Follow-up issue: https://github.com/ruvnet/ruflo/issues/1689
• Cloud Build configs: ruflo/src/ruvocal/cloudbuild.yaml, ruflo/src/ruvocal/mcp-bridge/cloudbuild.yaml
• .gcloudignore (CRITICAL — see resolved root cause): ruflo/src/ruvocal/.gcloudignore
• Web Worker: ruflo/src/ruvocal/src/lib/wasm/{wasm.worker.ts,workerClient.ts}
• Help modal: ruflo/src/ruvocal/src/lib/components/RufloHelpModal.svelte
• Live URLs: https://flo.ruv.io/ · https://ruflo.ruv.io/ · https://ruvocal.ruv.io/
• Related deployment ADR: ADR-029 (HF Chat UI on Cloud Run)