mermail.app WebMCP audit

Name: mermail.app WebMCP audit
Creator: ora

Rescan

audited Sep 2, 2026in 14s

94/ 100100% of the applicable check weight evaluated

3 tools registered. Strongest in shared experience, weakest in trust.

Shared experience100

Task completion100

Tool quality90

Trust83

https://mermail.app

Tools

3 read, 0 write

Loading map

get_status

Read the public Mermail service health status.Answers a question. Declared read only.

pagehttps://mermail.app/

implementation

viaimperative

entry pointprovideContext

registered after746ms

executepresent

api surfaceTakes no parameters.

annotations

read onlytrue

untrusted contentnot declared

titlenot declared

1 finding

warningDescription quality

weight 5

3 of 3 tool descriptions leave an agent guessing: get_status Omits what comes back, and what it changes..

get_status: weak; get_pricing: weak; start_signup: weak

fix

{
  name: "get_status",
  description: "Describe what this tool does, when to use it, and what it returns."
}

tool json

{
  "name": "get_status",
  "description": "Read the public Mermail service health status.",
  "inputSchema": {
    "type": "object",
    "properties": {},
    "additionalProperties": false
  },
  "annotations": {
    "readOnlyHint": true
  }
}

Findings

Shared experience

100 / 100 · weight 30

passPage experience

weight 20

The page a person sees holds up next to the agent surface: a working interface, visible actions, readable content, nothing in the way.

passHuman parity

weight 10

The person co-browsing can see and use this page - the same page the agent's tools act on.

Task completion

100 / 100 · weight 25

passTool selection

weight 15

An agent chose an existing, callable tool and built a schema-valid call for all 2 canonical intents, each matching the kind of tool its intent needs. Nothing was executed, so this verifies selection, not outcomes.

not applicableCoverage vs. site type

weight 10

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.

Tool quality

90 / 100 · weight 25

passRegistration timing

weight 1

Every measured tool registered within 746ms of navigation.

toolget_pricing

passCanonical entry point

weight 3

All 3 tools register on the canonical document.modelContext entry point.

passSchema validity

weight 4

All 3 declared input schemas are structurally valid object schemas.

passSchema quality

weight 4

3 tools declare no parameters, and every description stays within Chrome's size guidance.

passNaming quality

weight 2

All 3 tool names are consistent, verb-led, and within Chrome's size guidance.

passStub detection

weight 4

All 3 tools declare an execute handler.

passRegistration errors

weight 2

No tool registration threw during the capture.

warningDescription quality

weight 5

3 of 3 tool descriptions leave an agent guessing: get_status Omits what comes back, and what it changes..

toolget_status

get_status: weak; get_pricing: weak; start_signup: weak

fix

{
  name: "get_status",
  description: "Describe what this tool does, when to use it, and what it returns."
}

Trust

83 / 100 · weight 20

passAnnotations present

weight 6

All 2 read-shaped tools declare readOnlyHint: true - the one declared claim that lets an agent treat a call as safe to make without asking.

warningAnnotation mismatch

weight 6

1 tool declares readOnlyHint: true although the name says the call writes (start_signup).

toolstart_signup

start_signup: readOnlyHint=true

fix

// readOnlyHint must match what the tool actually does - drop it (or set false) on a tool that writes.
{ name: "start_signup", annotations: { readOnlyHint: false } }

not applicableUntrusted content hint

weight 4

No tool's contract suggests it returns text written by somebody other than the site, so there is nothing to flag as untrusted.

not applicableInjection surface

weight 4

No tool's metadata carries instruction-shaped text aimed at the agent reading it. This check only ever flags; it never credits a site.

Tool selection

100% across 2 intents

I want to get status on this site.ok

choseget_statusexpected get statuskind matched

arguments

{}

I want to start signup on this site.ok

chosestart_signupexpected start signupkind matched

arguments

{}

model: gemini-2.5-flash

Add the tools this site is missing

Our scanner reads your website and suggests the right WebMCP tools for it.

The open source webmcp plugin teaches your coding agent to audit a site, implement tools on document.modelContext, and verify them in a real browser. npx @ora-ai/webmcp-verify runs the verification on its own. No signup, no hosted service.

how this was captured

observed via: capture shim (Chromium 148.0.7778.96)
chrome: 148.0.7778.96
capture shim: v2
spec snapshot: 2026-08-26
mode: fast
pages: 1 - entry page only
tools: 3
run time: 14s
finished: Sep 2, 2026

Checked the way in-browser agents discover tools: the top-level document's modelContext registry, read after the page settles.