feat: Add destructiveHint and openWorldHint tool annotations

[bryankthompson]

Summary

This PR adds the missing MCP tool annotations (destructiveHint and openWorldHint) to all 26 tools in chrome-devtools-mcp.

Changes

• Updated ToolDefinition.ts: Added optional destructiveHint and openWorldHint fields to the annotations interface
• Added annotations to all 26 tools:
  • openWorldHint: true for all tools (browser automation inherently interacts with external websites)
  • destructiveHint: true for closePage, navigatePage, and evaluateScript (operations that can cause irreversible changes)
  • destructiveHint: false for other write operations (reversible modifications like click, fill, hover)

Why These Annotations Matter

Per the MCP specification:

• openWorldHint: Indicates tools that interact with an "open world" of external entities. All browser automation tools interact with external websites, so this is true for all tools.
• destructiveHint: Indicates tools that may perform irreversible updates. This helps AI assistants determine when to request user confirmation.

Tools Summary

Category	Tools	destructiveHint
Navigation	closePage, navigatePage	true (irreversible)
Script	evaluateScript	true (can modify page state)
Input	click, hover, fill, drag, fillForm, uploadFile, pressKey, handleDialog	false
Debugging	screenshot, takeSnapshot, listConsoleMessages, getConsoleMessage	false
Network	listNetworkRequests, getNetworkRequest	N/A (readOnly)
Performance	startTrace, stopTrace, analyzeInsight	N/A (readOnly)
Other	newPage, selectPage, listPages, resizePage, emulate, waitFor	false or N/A

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[OrKoN]

I am not sure I agree with the destructiveHint classification. click, hover, fill, drag, fillForm, uploadFile, pressKey can also trigger navigations and modify the page state. Also, closePage and navigatePage are reversible as they pages can be re-opened and navigated. I think in all cases the destructiveness depends on the payload and cannot be inferred on the tool level. WDYT @sebastianbenz @natorion ? I think openWorldHint can be added.

[sebastianbenz]

+1 to Alex's comments about descructive hint. These steps are also not something where I would want to have a user confirmation.

[bryankthompson]

Thanks @OrKoN and @sebastianbenz for the thoughtful review!

You're right - the destructiveness of browser automation tools is entirely payload-dependent. A click on a "Delete Account" button is destructive, but a click on a "Read More" link is not. This can't be reliably inferred at the tool level.

I've updated the PR to:

1. Remove all destructiveHint annotations - since destructiveness is context-dependent
2. Keep openWorldHint: true on all tools - they all interact with external web content
3. Keep readOnlyHint: true only for pure query tools (list_pages, select_page, list_console_messages, etc.)

This approach accurately reflects that these tools interact with unbounded external web resources without incorrectly triggering confirmation prompts.

[sebastianbenz]

Looking at the spec, it seems like openWorldHint is already true by default. Hence, I don't see much value in explicitly adding it here.

[natorion]

Looking at the spec, it seems like openWorldHint is already true by default. Hence, I don't see much value in explicitly adding it here.

I agree.

[bryankthompson]

Thanks for the feedback @sebastianbenz @natorion - you're absolutely right that openWorldHint: true is redundant since that's the spec default.

However, I believe the PR still provides concrete value through readOnlyHint: true on genuinely read-only tools. Unlike openWorldHint, readOnlyHint defaults to false, so explicitly setting it enables MCP clients to auto-approve safe operations without user confirmation.

Proposed changes:

• ❌ Remove all openWorldHint: true annotations (redundant)
• ✅ Keep readOnlyHint: true on query-only tools (getPageInfo, getScreenshot, findElement, getConsoleMessages, etc.)
• ✅ Keep title annotations for human-readable display

This focused approach addresses your concern about redundancy while still providing value for client implementations.

Would this revised scope be acceptable?

[sebastianbenz]

The read-only hints are already in the code base. Closing this PR for now. Thanks for flagging this nevertheless.