Jev × WebMCP
Chrome extension that converts a page's WebMCP tool schemas into Jev questions to pick a tool and fill its arguments from what you type.
Overview
Jev x WebMCP is a Chrome side-panel extension that uses Jev to select and populate WebMCP tool calls from user input. It discovers the tools the current page exposes and, as you type, shows predicted calls with confidence and latency; for example, asking for gluten-free items in the bakery aisle produces a search_products call with department Bakery and a gluten-free filter at 98% in 164 ms. No site-specific configuration is needed.
The core idea is a schema-to-question conversion. The tool list becomes one Choice over names and descriptions plus none of these; enums and consts become Choices over allowed values; booleans become Nouls; arrays of enums become one Noul per member; small integer ranges become Choices; free-text strings become a Choice over spans of the user's own words; other numbers become a Choice over numbers the user stated, parsed in code; and optional parameters get an is-it-stated Noul so defaults stand. It requires Chrome 149+ with WebMCP, has no build step, keeps the key in chrome.storage and grants host access one site at a time.
What the decision model decides
| Type | Question | Answers |
|---|---|---|
| Choice | Which of the page's WebMCP tools does this sentence mean, or none of these? | — |
| Choice | Which allowed value (or span of the user's words) fills this argument? | — |
| Yes / no | Is this optional argument stated in the input? | — |
How it works
- Discover WebMCP tools on the current page
- Convert schemas into Choice and Noul questions
- Jev answers as the user types
- Show predicted call with confidence and latency
Strengths
- Generic across sites via schemas
- Never generates free text; picks the user's own spans
- Optional parameters keep defaults unless stated
Caveats
- Requires Chrome 149+ with WebMCP enabled
- Few sites expose WebMCP tools yet
Getting started
Load the folder unpacked in chrome://extensions, open the side panel, add a TypeSafe key and enable it on a WebMCP site.At a glance
- Type
- Browser extension
- Status
- prototype
- Language
- JavaScript
- Runtime
- Browser extension
- Has code
- yes
Use cases and integrations
How curated lists describe it
Chrome extension that discovers the WebMCP tools a page exposes and has Jev choose which one a sentence means, then fills in its arguments.
MrJev/awesome-jev
Frequently asked questions
How are free-text arguments filled?
As a Choice over spans of the user's own words, so nothing is generated.
Does it need per-site setup?
No, it works from the page's WebMCP schemas.
What browser does it need?
Chrome 149 or newer with WebMCP available.
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