feverup.com WebMCP audit

Rescan
audited Aug 28, 2026in 6s
63/ 100

4 tools registered. Strongest in WebMCP use, weakest in human experience.

WebMCP use89
Usefulness63
Human experience0
about:blank

No agent run recorded yet.

No steps recorded

Tools

/en
toggle_plan_favorite: fail

toggle_plan_favorite

Adds or removes a plan from the user's favorites. If the plan is already a favorite it will be removed; otherwise it will be added. Works on any page that shows plan cards (gallery or calendar view).Takes an action on the site.
pagehttps://feverup.com/en
implementation
viaimperative
entry pointnavigator
registered after783ms
executepresent
api surface
planIdrequired
annotations
read onlyfalse
destructivenot declared
idempotentnot declared
open worldnot declared
untrusted contentnot declared
titlenot declared
2 findings
failCanonical entry point
0 / 4
Every tool registers through the deprecated navigator.modelContext alias; move them to document.modelContext before the alias is removed.
fix
// Use the canonical entry point - navigator.modelContext is deprecated.
document.modelContext.provideContext({ tools: [/* ... */] });
warningHuman parity
0 / 8
4 of 4 tools run through the JavaScript API with no visible counterpart, so the person co-browsing cannot see what the agent is offered. Declarative forms (or at least a title annotation) close the gap.
toggle_plan_favorite, home_list_cities, home_navigate_to_city, webmcp_get_page_summary
fix
<!-- Give the tool a visible counterpart: a declarative form is one the person can see and use too. -->
<form toolname="toggle_plan_favorite" tooldescription="...">
  <!-- the same action, as UI -->
</form>
tool json
{
  "name": "toggle_plan_favorite",
  "description": "Adds or removes a plan from the user's favorites. If the plan is already a favorite it will be removed; otherwise it will be added. Works on any page that shows plan cards (gallery or calendar view).",
  "inputSchema": {
    "additionalProperties": false,
    "properties": {
      "planId": {
        "description": "The numeric plan ID to add or remove from favorites.",
        "minimum": 1,
        "type": "integer"
      }
    },
    "required": [
      "planId"
    ],
    "type": "object"
  },
  "annotations": {
    "readOnlyHint": false
  }
}
Showing toggle_plan_favorite

Findings

WebMCP use

89 / 100 · weight 50
passTools registered
4 / 4
4 tools registered across 1 page.
passReal-browser eligible
8 / 8
A real browser exposes modelContext natively on this page, so the tools registered here are visible to an agent today.
passRegistration timing
4 / 4
Every measured tool registered within 816.0999999046326ms of navigation.
toolhome_navigate_to_city
failCanonical entry point
0 / 4
Every tool registers through the deprecated navigator.modelContext alias; move them to document.modelContext before the alias is removed.
tooltoggle_plan_favorite
fix
// Use the canonical entry point - navigator.modelContext is deprecated.
document.modelContext.provideContext({ tools: [/* ... */] });
passSchema validity
5 / 5
All 4 tools declare a structurally valid object input schema.
passSchema quality
4 / 4
All 4 tool schemas describe their parameters and stay within Chrome's size guidance.
passStub detection
5 / 5
All 4 tools declare an execute handler.
passAnnotations present
4 / 4
All 4 tools declare a readOnlyHint, so an agent knows which calls change state.
passAnnotation mismatch
3 / 3
No tool claims to be read-only while its name says it writes (4 declared hints checked).
not applicableUntrusted content hint
0 / 2
No tool's contract suggests it returns text written by somebody other than the site, so there is nothing to flag as untrusted.
passRegistration errors
2 / 2
No tool registration threw during the capture.
warningToolchange coherence
1 / 2
4 tools were registered but the page never dispatched a toolchange event, so an agent subscribed to registry updates never learns they exist.
fix
document.modelContext.dispatchEvent(new Event("toolchange"));
not applicableInjection surface
0 / 3
The injection-surface model hop returned no usable result, so tool contracts were not reviewed for injection surface.

Usefulness

63 / 100 · weight 30
warningNaming quality
1.3 / 2
Tool naming makes selection harder than it needs to be: 3 names do not start with a verb (home_list_cities).
toolhome_list_cities
fix
{ name: "home_list_cities" /* short, unique, verb-based */ }
not applicableDescription quality
0 / 6
The description-quality model hop returned no usable result, so descriptions were not rated.
not applicableTool selection
0 / 14
The tool-selection model hop returned no usable result.
not applicableCoverage vs. site type
0 / 8
This tool set does not place the site in a category with a known expected tool shape, so there is no coverage baseline to score it against.

Human experience

0 / 100 · weight 20
warningHuman parity
0 / 8
4 of 4 tools run through the JavaScript API with no visible counterpart, so the person co-browsing cannot see what the agent is offered. Declarative forms (or at least a title annotation) close the gap.
tooltoggle_plan_favorite
toggle_plan_favorite, home_list_cities, home_navigate_to_city, webmcp_get_page_summary
fix
<!-- Give the tool a visible counterpart: a declarative form is one the person can see and use too. -->
<form toolname="toggle_plan_favorite" tooldescription="...">
  <!-- the same action, as UI -->
</form>
not applicablePage experience
0 / 12
The page-experience model hop returned no usable result, so the page was not graded.

Tool selection

The tool-selection model hop returned no usable result.
how this was captured
chrome
148.0.7778.96
capture shim
v1
spec snapshot
2026-08
mode
fast
pages
1
tools
4
run time
6s
finished
Aug 28, 2026