docs(forms): show WebMCP tool state with the demo stand-in

[erkamyaman]

Summary

• Forms docs: state that the overlay has no early hook, so a WebMCP tool registered before it loads is only seen through the browser's tool list (and its calls are not recorded), or not at all without one.
• Forms docs: add "Try WebMCP in the demo", which walks through the demo's sign_up tool, Fill as an agent, and the agent origin in the timeline.
• Demo apps docs: list the modelContext stand-in and provideExperimentalWebMcpForms() in the demo wiring.

The stand-in itself (src/app/examples/webmcp-demo.ts) shipped with #225. It is only installed when neither document.modelContext nor navigator.modelContext exists, which is Angular's own lookup order.

Verification

• Demo SSR build. inspect-forms over MCP reports sign_up as registered: seen: "list" on a direct load, and seen: "register" with a recorded submitted call after navigating from /. form-history shows the agent origin.
• pnpm test:devtools, pnpm typecheck, pnpm format:check and pnpm docs:build pass.

Closes #166

Summary by CodeRabbit

• Documentation
  • Expanded the Angular Travel demo guide with details on the WebMCP stand-in and the sign_up tool used by Fill as an agent.
  • Clarified how tool registration timing affects visibility and call recording in the Forms overlay, with examples for different page-loading paths.
  • Explained that browsers with built-in WebMCP use their own implementation, and Fill as an agent relies on an agent calling sign_up.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: defaults
• Review profile: CHILL
• Plan: Advanced
• Run ID: 3c278f89-e7fc-44ea-b8a9-4b417ed9ec52

📥 Commits

Reviewing files that changed from the base of the PR and between d25a3a6 and efd97f5.

📒 Files selected for processing (2)

• apps/docs/src/content/contributing/demo-apps.md
• apps/docs/src/content/inspectors/forms.md

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📝 Walkthrough

Walkthrough

The documentation now describes the demo app’s WebMCP stand-in and Signal Forms tool setup. It also explains how tool registration timing and browser-provided modelContext affect Forms inspector recording.

Changes

WebMCP forms documentation

Layer / File(s)	Summary
Document WebMCP setup and recording behavior apps/docs/src/content/contributing/demo-apps.md, apps/docs/src/content/inspectors/forms.md	The demo app guide documents the development stand-in and sign_up tool. The Forms inspector guide describes recording behavior when the overlay loads before or after tool registration, including when the browser provides modelContext.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~5 minutes

Change: Other

Merge Risk: ⚪ Minimal · up to efd97

This documentation change accurately describes the demo’s WebMCP setup and recording behavior; no material merge risk remains.

Architecture Summary

Architecture risk: 🔵 Low · up to efd97

The change affects 1 system.

Changed systems: apps/docs

Architecture concerns
No architecture-level concerns identified.

Review details

Systems and components

• observed — apps/docs (service) was modified; 2 changed files map to changed impact.

Before / after behavior

• observed — Modified behavior in apps/docs/src/content/contributing/demo-apps.md: The setup table adds the WebMCP stand-in to the src/main.ts description and provideExperimentalWebMcpForms() to src/app/app.config.ts; the server setup is unchanged.
• observed — Modified behavior in apps/docs/src/content/contributing/demo-apps.md: Adds documentation for the development WebMCP stand-in, including its conditional installation before bootstrap, the sign_up tool registration and use in the Signal Forms example, and a link to further instructions.
• observed — Modified behavior in apps/docs/src/content/inspectors/forms.md: Adds guidance that tools registered before the overlay loads have unrecorded calls, then documents demo setup and the resulting behavior for overlay-first, direct-route, and native-modelContext cases.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: documenting WebMCP tool state in the Forms docs using the demo stand-in.
Linked Issues check	✅ Passed	Issue [#166] requests WebMCP registration and call state, schema diagnostics, missing-context and duplicate-name warnings, and an agent timeline origin. At the reviewed head, FormsWebMcp displays re…
Out of Scope Changes check	✅ Passed	Both documentation changes support issue [#166]. The Forms docs explain WebMCP visibility and demonstrate the tool flow. The Demo apps docs describe the stand-in and provider setup used by that demons…
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…

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