verify

Verifying AgentTools changes at runtime

Wolfram Language side (tools, server, UI results)

• Always set WOLFRAMSCRIPT_KERNELPATH="C:/Program Files/Wolfram Research/Wolfram/15.0/wolfram.exe" (or newer). Plain wolframscript may pick an older kernel; AgentTools requires 15.0+, and under an older kernel PacletDirectoryLoad + Get["Wolfram`AgentTools`"] silently falls back to the installed Repository paclet — you exercise the wrong code. Confirm with FindFile["Wolfram`AgentTools`"] → must resolve under the dev directory.
• Load the dev paclet: PacletDirectoryLoad["H:\\Documents\\AgentTools"]; Get["Wolfram`AgentTools`"].
• To drive a tool exactly as the MCP server dispatches it, call its registered "Function" (see $defaultMCPTools[name] in Kernel/Tools/*.wl) with the parsed-args association, e.g. Wolfram`AgentTools`Tools`WolframLanguageEvaluator`Private`evaluateWolframLanguage[<|"code" -> ...|>].
• To trigger the MCP Apps UI path (cloud-deployed notebook + _meta.notebookUrl), first set Wolfram`AgentTools`Common`$clientSupportsUI = True and be cloud-connected. Export the result with Developer`WriteRawJSONFile — it is the exact content/_meta payload a host forwards to a viewer.
• For an A/B against pre-change behavior, git worktree add <scratch>/head-copy HEAD and point PacletDirectoryLoad at the worktree in a second wolframscript run. Use a different input (the deploy target is content-hashed, same input overwrites the same cloud object). Remove the worktree afterwards.

MCP Apps viewers (Assets/Apps/*.html)

• All viewers speak the same iframe protocol: they send ui/initialize (reply with {protocolVersion, hostInfo, hostContext}), then notify ui/notifications/initialized; after that, post {jsonrpc:"2.0", method:"ui/notifications/tool-result", params:{content, _meta}} into the iframe.
• Harness that works: a host.html that iframes the viewer and plays the host role over postMessage + a no-dep node static server + Playwright (npm i playwright locally; chromium via npx playwright install chromium). Set colorScheme: "dark" on the browser context to reproduce dark-host bugs; the embed needs real network (unpkg CDN + wolframcloud.com) and takes 10–60 s.
• The notebook embedder (useShadowDOM: true) attaches an open shadow root to a wrapper <div> it creates inside the container, not to the container itself. Wait for embed completion by recursively searching open shadow roots for expected notebook text; read computed styles with getComputedStyle on shadow-tree elements.
• Playwright frame-picking gotcha: the host page URL carries the viewer filename in its query string, so match f !== page.mainFrame() when locating the viewer frame.
• Verified evidence to capture: computed color of shadow text leaves (dark-theme leak shows as rgb(224, 224, 224)), computed font-family, and full-page screenshots.