readmbox.com WebMCP audit

Name: readmbox.com WebMCP audit
Creator: ora

Rescan

audited Aug 28, 2026in 4s

55/ 100

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

WebMCP use55

Usefulness92

Human experience0

about:blank

No agent run recorded yet.

No steps recorded

Tools

get_mailbox_status

Report whether an MBOX file is open in this tab and what is in it: message count, date span, how many messages the current filters match, and whether the mailbox is fully readable. Call this first.Takes an action on the site.

pagehttps://readmbox.com/

implementation

viaimperative

entry pointnavigator

registered after214ms

executepresent

api surfaceTakes no parameters.

annotations

read onlynot declared

destructivenot declared

idempotentnot declared

open worldnot declared

untrusted contentnot declared

titlenot declared

3 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: [/* ... */] });

failAnnotations present

0 / 4

6 of 6 tools declare no readOnlyHint, so an agent cannot tell a read from a write without guessing from the name.

get_mailbox_status, list_messages, read_message, filter_by_date, clear_filters

fix

{
  name: "get_mailbox_status",
  annotations: { readOnlyHint: true, destructiveHint: false, idempotentHint: true }
}

warningHuman parity

0 / 8

6 of 6 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_mailbox_status, list_messages, read_message, filter_by_date, clear_filters

fix

<!-- Give the tool a visible counterpart: a declarative form is one the person can see and use too. -->
<form toolname="get_mailbox_status" tooldescription="...">
  <!-- the same action, as UI -->
</form>

tool json

{
  "name": "get_mailbox_status",
  "description": "Report whether an MBOX file is open in this tab and what is in it: message count, date span, how many messages the current filters match, and whether the mailbox is fully readable. Call this first.",
  "inputSchema": {
    "type": "object",
    "properties": {}
  },
  "annotations": {}
}

Findings

WebMCP use

55 / 100 · weight 50

passTools registered

4 / 4

6 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 214.70000004768372ms of navigation.

toolscan_messages

failCanonical entry point

0 / 4

Every tool registers through the deprecated navigator.modelContext alias; move them to document.modelContext before the alias is removed.

toolget_mailbox_status

fix

// Use the canonical entry point - navigator.modelContext is deprecated.
document.modelContext.provideContext({ tools: [/* ... */] });

passSchema validity

5 / 5

All 6 tools declare a structurally valid object input schema.

warningSchema quality

2 / 4

3 of 6 tool schemas are harder for an agent to use than they need to be: list_messages declares no required list, so an agent cannot tell which parameters are mandatory.

toollist_messages

list_messages: declares no required list, so an agent cannot tell which parameters are mandatory; filter_by_date: declares no required list, so an agent cannot tell which parameters are mandatory; sca

fix

{
  name: "list_messages",
  inputSchema: {
    type: "object",
    properties: {
      query: { type: "string", description: "What to search for" }
    },
    required: ["query"]
  }
}

passStub detection

5 / 5

All 6 tools declare an execute handler.

failAnnotations present

0 / 4

6 of 6 tools declare no readOnlyHint, so an agent cannot tell a read from a write without guessing from the name.

toolget_mailbox_status

get_mailbox_status, list_messages, read_message, filter_by_date, clear_filters

fix

{
  name: "get_mailbox_status",
  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

6 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

92 / 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 (scan_messages).

toolscan_messages

fix

{ name: "scan_messages" /* 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

toolget_mailbox_status

get_mailbox_status, list_messages, read_message, filter_by_date, clear_filters

fix

<!-- Give the tool a visible counterpart: a declarative form is one the person can see and use too. -->
<form toolname="get_mailbox_status" 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: 6
run time: 4s
finished: Aug 28, 2026