Published 25 Aug 2026 · last checked 9 Oct 2026: Build Agent Ready Websites with ChatGPT (OpenAI Developer Community, staff post)'Site tools are ChatGPT's implementation of the proposed WebMCP standard... In the built-in browser in the ChatGPT desktop app, ChatGPT Work and Codex can discover and use these tools.' The docs (https://learn.chatgpt.com/docs/webmcp) say it supports a subset: document.modelContext.registerTool, no declarative form attributes, no tools in iframes. ChatGPT Atlas is not named.
Published 6 Oct 2026 · last checked 9 Oct 2026: MicrosoftEdge/webmcp-labs #17 (reply from Victor Huang, PM at Microsoft)'There's currently no public way to test WebMCP with Copilot in Edge, including the Copilot drawer. The WebMCP testing flag enables testing of the page APIs, but doesn't make the integration available in Copilot Mode.'
Published 28 Sept 2026 · last checked 9 Oct 2026: Chrome Platform Status: WebMCPOrigin trial runs Chrome 149–156 (developer trial behind a flag from 146). Implementation status is 'Proposed' and it is not shipped by default. Origin trial announced 2026-06-09 (https://developer.chrome.com/blog/ai-webmcp-origin-trial).
EdgePartial support
Published 31 Aug 2026 · last checked 9 Oct 2026: MicrosoftEdge/webmcp-labs READMETestable in Edge Canary/Dev via about://flags/#enable-webmcp-testing. Not in stable Edge. Date is the README's last commit.
SafariNot supported
Published 3 Jun 2026 · last checked 9 Oct 2026: WebKit standards-positions #670: WebMCPLabelled 'position: oppose'. WebKit wrote: 'we do not think a parallel agent-facing tool layer is the right solution'. Its concerns include duplication, privacy, security and venue. Mozilla's position (mozilla/standards-positions#1412) is labelled 'neutral', which is not a denial, so Firefox is left out of declared.
WebMCP lets a page register tools that an agent in the browser can call. The
tools only exist in the live page, so this check reads the page open in your
active tab rather than fetching anything. It looks for:
tools registered through document.modelContext, the entry point the spec
settles on;
tools registered through navigator.modelContext, the earlier alias, which
Chrome 150 and later deprecate; and
declarative tools: elements such as forms marked up with a toolname
attribute, and whether each has a tooldescription.
Where it can, it reports how many tools are registered.
Results
Status
When
Pass
Tools are registered through document.modelContext
Pass
Tools are registered through navigator.modelContext, with a note to migrate
Pass
The page declares toolname tools, with a note if any lack a tooldescription
N/A
No WebMCP tools of either kind were found on the page
Unmeasured
The extension could not read the page, so it could not look
Unmeasured usually means the site you scanned is not the one open in the active
tab. Open it there and scan again.
How to fix
To offer tools, register them through document.modelContext in the page’s
script. If you already use navigator.modelContext, switch to
document.modelContext.
For a form, you can declare it as a tool in the markup instead, and describe
what it does so an agent knows when to use it:
<formtoolname="search-products"tooldescription="Search the product catalogue by keyword."><labelfor="q">Search</label><inputid="q"name="q"type="search"/><buttontype="submit">Search</button></form>
Announced means the vendor’s own docs or announcement say so. Published is the date on the vendor’s own page, where it has one. Checked is the last time our weekly research found that page still saying so.
Agent
Status
Source
AI assistants
ChatGPT OpenAI
Partial support
partialBuild Agent Ready Websites with ChatGPT (OpenAI Developer Community, staff post)Published · Checked 'Site tools are ChatGPT's implementation of the proposed WebMCP standard... In the built-in browser in the ChatGPT desktop app, ChatGPT Work and Codex can discover and use these tools.' The docs (https://learn.chatgpt.com/docs/webmcp) say it supports a subset: document.modelContext.registerTool, no declarative form attributes, no tools in iframes. ChatGPT Atlas is not named.
noMicrosoftEdge/webmcp-labs #17 (reply from Victor Huang, PM at Microsoft)Published · Checked 'There's currently no public way to test WebMCP with Copilot in Edge, including the Copilot drawer. The WebMCP testing flag enables testing of the page APIs, but doesn't make the integration available in Copilot Mode.'
partialChrome Platform Status: WebMCPPublished · Checked Origin trial runs Chrome 149–156 (developer trial behind a flag from 146). Implementation status is 'Proposed' and it is not shipped by default. Origin trial announced 2026-06-09 (https://developer.chrome.com/blog/ai-webmcp-origin-trial).
Edge Microsoft
Partial support
partialMicrosoftEdge/webmcp-labs READMEPublished · Checked Testable in Edge Canary/Dev via about://flags/#enable-webmcp-testing. Not in stable Edge. Date is the README's last commit.
Safari Apple
Not supported
noWebKit standards-positions #670: WebMCPPublished · Checked Labelled 'position: oppose'. WebKit wrote: 'we do not think a parallel agent-facing tool layer is the right solution'. Its concerns include duplication, privacy, security and venue. Mozilla's position (mozilla/standards-positions#1412) is labelled 'neutral', which is not a denial, so Firefox is left out of declared.
No evidence yet20
Claude
Gemini
Perplexity
Copilot
Meta AI
ChatGPT Atlas
Comet
Dia
Claude Code
Cursor
GitHub Copilot
Windsurf
CCBot
Applebot
Amazonbot
Bytespider
Cohere
Mistral
DuckAssist
Firefox
Names and marks belong to their owners and are used only to identify products. None of these vendors is affiliated with Sitebulb. Spotted something out of date? Send a correction.
Adoption on the top 100 sites
0%
0 of 100 measured sites implement it
Scanned 23 Oct 2026 with the Sitebulb Labs extension, against the Tranco list (tranco-56Z8N).
9 Oct 2026 0% → 23 Oct 2026 0%
Overview
3/9
Stalled
No meaningful support, or vendors have said no.
How this rating is worked out3 of 9 points
Factor
Points
Why
Vendor support
1 / 3
0 vendors supporting, 3 partly or planned
Top-100 adoption
0 / 3
0% of measured sites
Spec maturity
2 / 3
Standards-track draft
8 or more points is Established, 5 to 7 is Gaining traction, 2 to 4 is Speculative and under 2 is Stalled. A feature is also Stalled when more vendors have said no than yes. Read the spec.
Community insights
Sceptical
WebMCP occupies the worst of both worlds: it demands developer effort like server-side MCP but routes through the browser, creating a second-class copy that drifts from the UI.
Shopify’s Checkout team ran a similar experiment and found WebMCP to be 2.7x faster and 58% cheaper, with 60/60 successful attempts vs. 56/60 with browser automation!
Manveer ChawlaOn their blog, 13 Feb 2026Website
Suganthan MohanadasanCo-founder, Snippet DigitalOn their blog, 12 May 2026Website
Yoav WeissShopifyOn their blog, 12 Oct 2026Website