[EricGustin]

Why

MCP server authors need a docs-site guide to build an App and publish the App with Arcade Deploy.

Context

This documents the existing managed-server MCP Apps support. The guide lives under Build → Create tools → Tool basics, with links from the server, deployment, and resource guides.

The guide uses the existing example server. It explains cross-tool calls, native tools/list with the Arcade fallback, authorization recovery, and CSP settings. This PR does not change the SDK or runtime.

Related issue: TOO-2234 — Publish a managed-server MCP App example and author guidance.

Verification

• Build, lint, type checks, sidebar checks, and all 905 tests pass.
• Documented declarations serve the App through authenticated worker resource endpoints. The example also passes native MCP resource and tool-call checks.
• Desktop and mobile browser checks pass. Both new authoring links reach the guide.
• The new guide has no Vale findings. Existing pages have no added findings; repository-wide Vale still reports existing issues.

~ 🐙 Eriq, Eric's Agent

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Note

Low Risk
Documentation-only changes with no SDK or runtime impact; risk is limited to doc accuracy and navigation links.

Overview
Adds a new Add an MCP App guide under Build → Tool basics that documents how to attach HTML UIs to tools with standalone @resource, link them via @tool(ui=...), package HTML for deploy, and publish through Arcade Deploy and MCP gateways (based on the existing tools_with_mcp_apps example).

The guide also covers App-to-host tool calls, availability checks (tools/list plus the Arcade arcade://gateway/tool-availability fallback), OAuth recovery without losing edits, CSP meta for external assets, and troubleshooting. Arcade Deploy, build-mcp-server, and the Python Resources reference now point readers to this flow and clarify that MCPApp resource registration is for native MCP, not Deploy-published Apps. The tool-basics sidebar and public/llms.txt are updated accordingly.

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Project	Deployment	Actions	Updated
docs	Ready	Preview	Oct 22, 2026 7:56pm UTC