Atlas / MCP servers / karthiksubramanian07 / Marlo

MarloBLOCK

Name: Marlo
Author: karthiksubramanian07

mcp/karthiksubramanian07/marlo

MCP server by karthiksubramanian07 · a11y · accessibility · act rules · Audited 2026-10-13

Fixes accessibility violations and proves it. Multi-engine WCAG detection routed by measured accuracy, verified minimal-diff repairs, and a published error rate.

Verdict

BLOCK

Grade

Trust score

66 /100

Exposed tools

4 4r · 0w · 0d

Transport

streamable-http

License

MIT

Stars

Overview

From the repository's own README, as read at the audited commit. Badges and raw HTML are left out.

Our false positive rate is 5.6%. Here is how we measured it, and why we are printing it.

[](https://github.com/KarthikSubramanian07/Marlo/actions/workflows/ci.yml) [](calibration/README.md) [](calibration/README.md) [](LICENSE)

Every accessibility tool claims to be accurate. Not one of them will tell you how often it is wrong.

Marlo will. It checks pages against the official W3C ACT rule corpus, then measures itself against that same corpus and commits the result to this repository. The numbers are regenerated in CI on every push. When one gets worse, the build fails.

[trymarlo.pages.dev](https://trymarlo.pages.dev) · the numbers · where Marlo was wrong

The table nobody else publishes

Four engines, 513 official test case outcomes, one code path, no exemptions.

Marlo is third of four. Alfa and axe-core are both more precise and more sensitive, and the router sends 18 rules to axe-core against 20 to Marlo's own engine.

Nobody edited that. Marlo's engine goes through the same harness, on the same corpus, with no special case, because a table where the author's own engine

Read from source at commit 80e6f9b2c940OBSERVED · 2026-10-13

Connect

Built from this server's own package name, version and transport as found in its source — not copied from anyone's documentation, so it cannot drift against a page we do not control.

claude-code

claude mcp add schema -- npx -y @marlo/[email protected]

claude-desktop

{
  "mcpServers": {
    "schema": {
      "command": "npx",
      "args": [
        "-y",
        "@marlo/[email protected]"
      ]
    }
  }
}

Exposed tools (4)

4 read · 0 write · 0 destructive.

Tool	Risk	Description
`marlo_coverage`	read	Read measured Marlo coverage and engine accuracy. Report the limits alongside findings; this does not scan a page.
`marlo_explain_rule`	read	Read one ACT rule and its measured engine accuracy before interpreting a finding. This does not evaluate HTML.
`marlo_list_rules`	read	List ACT rule metadata, implementation status, measurements and routing. This is calibration evidence, not a page scan.
`marlo_scan_html`	read	Check HTML source against the ACT rules Marlo implements. Returns findings with the

Trust audit

BLOCKgrade D · trust 66/100 Do not install this without reading the findings. The audit found something that could harm you or your machine.

Layer	What it checks	Result
L0	Provenance & inventory	PASS
L1	Static analysis of the code	FAIL
L2	Instruction surface (what it tells the agent)	FAIL
L3	Class-specific surface	WARN
L4	Behavioural (sandbox)	SKIPPED

What the source does

Filesystem: none-observed
Network: declared (4 observation(s))
Shell: declared (1 observation(s))
Dependencies: pinned
Secrets in source: none-found

Findings (24)

HIGHCode injection · code.eval_exec · CWE-78, CWE-94, CWE-95

packages/engines/src/dom.ts:21

eval(source: string): unknown;

Why it matters. evaluates text as code

Fix. remove; use a parser or a dispatch table

HIGHPrompt injection · prompt.zero_width · CWE-94, CWE-1427

corpus/real/pages/form-01/index.html:10

<style media="all" data-marlo-inlined-from="https://design-system.service.gov.uk/stylesheets/main-41435c0ffee0fe1f01c0fea807b2115a.css">:root{--govuk-breakpoint-mobile: 20rem;--govuk-breakpoint-tablet

Why it matters. invisible characters in instruction text

Fix. strip non-printing characters

HIGHPrompt injection · prompt.zero_width · CWE-94, CWE-1427

corpus/real/pages/form-02/index.html:10

<style media="all" data-marlo-inlined-from="https://design-system.service.gov.uk/stylesheets/main-41435c0ffee0fe1f01c0fea807b2115a.css">:root{--govuk-breakpoint-mobile: 20rem;--govuk-breakpoint-tablet

Why it matters. invisible characters in instruction text

Fix. strip non-printing characters

MEDIUMNetwork egress · net.raw_ip · CWE-200, CWE-319

scripts/capture-screenshots.mjs:87

origin: `http://127.0.0.1:${String(typeof address === 'object' && address !== null ? address.port : 0)}`,

MEDIUMAuth / authz · mcp.remote_no_auth · CWE-287, CWE-862

streamable-http

Why it matters. a network transport with no auth environment variable found

Fix. require a token

LOWInventory / provenance · inv.hidden_file · CWE-1104

.dependency-cruiser.cjs

.dependency-cruiser.cjs

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWInventory / provenance · inv.hidden_file · CWE-1104

.mailmap

.mailmap

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWInventory / provenance · inv.hidden_file · CWE-1104

.prettierignore

.prettierignore

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWInventory / provenance · inv.hidden_file · CWE-1104

.prettierrc.json

.prettierrc.json

Why it matters. hidden member outside the usual dotfiles

Fix. review its purpose

LOWInformation disclosure · disclose.log_secret · CWE-209, CWE-532

.github/actions/marlo/check-scopes.mjs:184

console.log(`marlo: checking token scopes for the ${mode} mode.`);

LOWObfuscation / stealth · obf.base64_blob · CWE-506, CWE-94

corpus/real/pages/government-04/index.html:129

<style media="all" data-marlo-inlined-from="https://www.nasa.gov/_static/??-eJyNjssKwjAQRX/IGFIQcSHu3PoNk+nYhk4eZJKW/r2lKohd6Gq4wzmXq6ekMIZCoWhktxzlq0pcOxdEV5laUfcMnqaYh2fWtjputZSZSfYostMfJW8VEEnEWceu

LOWObfuscation / stealth · obf.base64_blob · CWE-506, CWE-94

corpus/real/pages/government-04/index.html:2007

<input type="hidden" class="gform_hidden" name="state_117" value="WyJ7XCIxXCI6W1wiNDJiNzUwMjNkZDk1ZTk4YjNmYTAzNGE5YmM5ZDgwNjhcIixcIjUwNGE0MTZkNDdmOGNlNGM2NDlkYTdjMDhmYzBiNDBhXCJdLFwiZ2Zvcm1fc3VibWlzc2

LOWObfuscation / stealth · obf.base64_blob · CWE-506, CWE-94

corpus/real/pages/news-01/index.html:25

@media print{#centralNotice{display:none}}.cn-closeButton{display:inline-block;background:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAUBAMAAAB/pwA+AAAAElBMVEUAAAAQEBDPz88AAABAQEDv7+9oe1vv

LOWObfuscation / stealth · obf.base64_blob · CWE-506, CWE-94

corpus/real/pages/news-02/index.html:11

.ui-helper-hidden{display:none}.ui-helper-hidden-accessible{border:0;clip:rect(0 0 0 0);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}.ui-helper-reset{margin:0;padding:0

LOWObfuscation / stealth · obf.base64_blob · CWE-506, CWE-94

corpus/real/pages/news-02/index.html:33

@media print{#centralNotice{display:none}}.cn-closeButton{display:inline-block;background:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAUBAMAAAB/pwA+AAAAElBMVEUAAAAQEBDPz88AAABAQEDv7+9oe1vv

LOWPrompt injection · prompt.transfer_instruction · CWE-94, CWE-1427

corpus/real/pages/application-01/index.html:19

*/@font-face{font-family:"Ionicons";src:url("https://code.ionicframework.com/ionicons/2.0.1/fonts/ionicons.eot?v=2.0.1");src:url("https://code.ionicframework.com/ionicons/2.0.1/fonts/ionicons.eot?v=2.

Why it matters. an instruction to move sensitive data to an outside destination

Fix. remove; a skill never needs the user's secrets off the machine

LOWPrompt injection · prompt.transfer_instruction · CWE-94, CWE-1427

corpus/real/pages/application-02/index.html:19

*/@font-face{font-family:"Ionicons";src:url("https://code.ionicframework.com/ionicons/2.0.1/fonts/ionicons.eot?v=2.0.1");src:url("https://code.ionicframework.com/ionicons/2.0.1/fonts/ionicons.eot?v=2.

Why it matters. an instruction to move sensitive data to an outside destination

Fix. remove; a skill never needs the user's secrets off the machine