yutori.com WebMCP audit

Rescan
audited Aug 28, 2026in 5s
65/ 100

4 tools registered. Strongest in usefulness, weakest in human experience.

WebMCP use69
Usefulness100
Human experience0
about:blank

No agent run recorded yet.

No steps recorded

Tools

/
get_yutori_overview: fail

get_yutori_overview

Return a short overview of Yutori and its products (Navigator API, Scouts, Delegate).Takes an action on the site.
pagehttps://yutori.com/
implementation
viaimperative
entry pointprovideContext
registered after664ms
executepresent
api surfaceTakes no parameters.
annotations
read onlynot declared
destructivenot declared
idempotentnot declared
open worldnot declared
untrusted contentnot declared
titlenot declared
2 findings
failAnnotations present
0 / 4
4 of 4 tools declare no readOnlyHint, so an agent cannot tell a read from a write without guessing from the name.
get_yutori_overview, get_navigator_model, list_developer_resources, get_started
fix
{
  name: "get_yutori_overview",
  annotations: { readOnlyHint: true, destructiveHint: false, idempotentHint: true }
}
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.
get_yutori_overview, get_navigator_model, list_developer_resources, get_started
fix
<!-- Give the tool a visible counterpart: a declarative form is one the person can see and use too. -->
<form toolname="get_yutori_overview" tooldescription="...">
  <!-- the same action, as UI -->
</form>
tool json
{
  "name": "get_yutori_overview",
  "description": "Return a short overview of Yutori and its products (Navigator API, Scouts, Delegate).",
  "inputSchema": {
    "type": "object",
    "properties": {},
    "additionalProperties": false
  },
  "annotations": {}
}
Showing get_yutori_overview

Findings

WebMCP use

69 / 100 · weight 50
passTools registered
4 / 4
4 tools registered across 1 page.
failReal-browser eligible
0 / 8
The page's code registers these tools, but a real visitor's browser does not get them yet: WebMCP needs a native modelContext or a current origin trial token, and this page has neither.
passRegistration timing
4 / 4
Every measured tool registered within 663.7999999523163ms of navigation.
toolget_navigator_model
passCanonical entry point
4 / 4
All 4 tools register on the canonical document.modelContext entry point.
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.
failAnnotations present
0 / 4
4 of 4 tools declare no readOnlyHint, so an agent cannot tell a read from a write without guessing from the name.
toolget_yutori_overview
get_yutori_overview, get_navigator_model, list_developer_resources, get_started
fix
{
  name: "get_yutori_overview",
  annotations: { readOnlyHint: true, destructiveHint: false, idempotentHint: true }
}
not applicableAnnotation mismatch
0 / 3
No tool declares a readOnlyHint, so there is no safety claim to contradict.
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

100 / 100 · weight 30
passNaming quality
2 / 2
All 4 tool names are consistent, verb-led, and within Chrome's size guidance.
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.
toolget_yutori_overview
get_yutori_overview, get_navigator_model, list_developer_resources, get_started
fix
<!-- Give the tool a visible counterpart: a declarative form is one the person can see and use too. -->
<form toolname="get_yutori_overview" 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
5s
finished
Aug 28, 2026