iammatthias.com WebMCP audit

Rescan
audited Aug 28, 2026in 7s
70/ 100

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

WebMCP use78
Usefulness90
Human experience20
about:blank

No agent run recorded yet.

No steps recorded

Tools

/
search_site: warning

search_site

Search this site's writing, photography notes, and recipes by keyword. Returns titles, excerpts, and both HTML and markdown URLs.Answers a question. Declared read only.
pagehttps://iammatthias.com/
implementation
viaimperative
entry pointdocument
registered after153ms
executepresent
api surface
queryrequired
limitoptional
annotations
read onlytrue
destructivefalse
idempotenttrue
open worldfalse
untrusted contentnot declared
titlenot declared
1 finding
warningHuman parity
1.6 / 8
4 of 5 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.
search_site, list_content, read_current_page, open_entry
fix
<!-- Give the tool a visible counterpart: a declarative form is one the person can see and use too. -->
<form toolname="search_site" tooldescription="...">
  <!-- the same action, as UI -->
</form>
tool json
{
  "name": "search_site",
  "description": "Search this site's writing, photography notes, and recipes by keyword. Returns titles, excerpts, and both HTML and markdown URLs.",
  "inputSchema": {
    "type": "object",
    "properties": {
      "query": {
        "type": "string",
        "description": "Search terms."
      },
      "limit": {
        "type": "integer",
        "description": "Maximum hits (1-50, default 10)."
      }
    },
    "required": [
      "query"
    ]
  },
  "annotations": {
    "readOnlyHint": true,
    "destructiveHint": false,
    "idempotentHint": true,
    "openWorldHint": false
  }
}
Showing search_site

Findings

WebMCP use

78 / 100 · weight 50
passTools registered
4 / 4
4 imperative tools and 1 declarative form 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. The 1 declarative form tool on the page stay usable regardless.
passRegistration timing
4 / 4
Every measured tool registered within 153.20000004768372ms of navigation. 1 further tool carried no measurable registration time.
toollist_content
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.
warningSchema quality
3.2 / 4
1 of 5 tool schemas are harder for an agent to use than they need to be: list_content declares no required list, so an agent cannot tell which parameters are mandatory.
toollist_content
list_content: declares no required list, so an agent cannot tell which parameters are mandatory
fix
{
  name: "list_content",
  inputSchema: {
    type: "object",
    properties: {
      query: { type: "string", description: "What to search for" }
    },
    required: ["query"]
  }
}
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

90 / 100 · weight 30
warningNaming quality
1.8 / 2
Tool naming makes selection harder than it needs to be: 1 name does not start with a verb (open_entry).
toolopen_entry
fix
{ name: "open_entry" /* 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

20 / 100 · weight 20
warningHuman parity
1.6 / 8
4 of 5 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.
toolsearch_site
search_site, list_content, read_current_page, open_entry
fix
<!-- Give the tool a visible counterpart: a declarative form is one the person can see and use too. -->
<form toolname="search_site" 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
5
run time
7s
finished
Aug 28, 2026