MCP HeartbeatTHE MCP OBSERVATORY
Public workspace

Explore

Evidence for your next connection.

Independent measurements of remote MCP servers. Every observation has a timestamp.

Read-only probes

MCP server · Code & DevOps

qart.uk QR studio

qart.uk MCP server: resolve scanned codes, browse the free pool, and buy QR artwork.

Checks passed
11 / 22

3 failed · 8 not measured

Median response
411 ms

Median of successful probes over 7 days

30-day uptime
Not measured

Share of countable probes over 30 days, including daily rollups. Auth challenges are excluded.

Discovered tools
8

Tool definitions returned by this server

Independent monitoring

Health & checks

Status history

Responded

The server completed its last measured handshake. This is an observation, not a guarantee.

Last checked
Check summary by test group
Test areaPassedFailedUnmeasured
ConnectionCan a client connect and discover tools?
500
Reliability & speedDoes it respond consistently and quickly?
004
Access & authenticationWhat is required to use this server?
102
Tool qualityAre the tool definitions usable by an agent?
310
Publisher identityCan the publisher be traced to its source?
222

Unmeasured means there is not enough evidence to decide. How these checks work

Inspect individual checks 22 recorded

Core

  • Pass
    Reachable

    Latest probe returned HTTP 200 in 411 ms.

  • Pass
    Valid handshake

    protocolVersion 2025-11-25, serverInfo.name qart-uk.

  • Pass
    Lists tools

    tools/list returned 8 tools.

  • Pass
    Current protocol

    Negotiated 2025-11-25. The bar is 2025-06-18 or newer.

  • Pass
    HTTPS

    The endpoint URL is https.

Performance

  • Not measured
    Fast (p50)

    Median latency 411 ms over 1 samples in 7 days. The bar is 1000 ms. Need at least 5 samples.

  • Not measured
    Consistent (p95)

    95th percentile 411 ms over 1 samples in 7 days. The bar is 3000 ms. Need at least 20 samples.

  • Not measured
    Reliable (uptime)

    1 of 1 attempts returned a tool list in 30 days (100%). The bar is 99%. Need at least 30 samples.

  • Not measured
    Stable tool list

    Fewer than two successful probes in 30 days, so tool-list stability is not measured.

Access

  • Pass
    Open access

    tools/list succeeded with no credential, and the record declares none.

  • Not measured
    Standard auth

    Auth is not required, so the OAuth metadata check does not apply.

  • Not measured
    Free tier cited

    No publisher quote has been checked.

Tools

  • Pass
    Tools described

    Every tool description is at least 20 characters.

  • Pass
    Valid input schemas

    Every inputSchema is a JSON Schema object.

  • Pass
    Parameters documented

    54 of 54 parameters have a description (100%). The bar is 80%.

  • Fail
    Safety hints

    8 tools set neither readOnlyHint nor destructiveHint.

Publisher

  • Pass
    Verified namespace

    Listed in the Official MCP Registry.

  • Fail
    Website matches publisher

    The website host does not match the reverse-domain namespace.

  • Fail
    Source repo linked

    No repository URL is on file.

  • Not measured
    Repo owner matches

    This namespace is not an io.github login, so the owner comparison does not apply.

  • Pass
    Recently updated

    Updated 2026-08-10T00:58:48.75487Z, within 180 days.

  • Not measured
    Open-source licence

    No GitHub repository to ask about a licence.

Start using qart.uk QR studio

Connect to this server

Choose your client, copy the configuration, then enable the server in your client’s MCP settings.

Run this command in your terminal, then restart Claude Code.

Claude Code

claude mcp add --transport http qart-uk-qr-studio https://qart.uk/api/mcp

Capabilities

Tools 8

browse_free_pool

List the QR artwork currently claimable for free on qart.uk, one per style, with a preview image URL for each. This is the ANONYMOUS shelf — the same selection every signed-out visitor sees, and these codes are what a guest can claim. Use it to show someone what is available or to describe the styles on offer. If you are acting for a signed-in account and want codes THAT account can actually claim, use browse_my_pool instead — the two storefronts differ, and a code from here may 403 on a claim.

Discovered
buy_qr_outright

How to buy ONE finished QR artwork with no account at all, paying from your own wallet over x402. Returns the live price and the exact request to make. This is the right tool when you have a wallet but no qart.uk account: get_credit_packs buys CREDITS, which still need an account to spend, and the Studio tools all require an OAuth token. This path requires neither — you GET https://qart.uk/api/v1/qr?url=..., it answers 402, you retry with a PAYMENT-SIGNATURE header, and the PNG comes back in the response body. You are charged ONLY if a real QR detector decodes the image: settlement runs after the scan verdict, so a request that produces nothing scannable is never settled and costs you nothing. Pay in USDC on Base — you do not need ETH, because the facilitator submits the transaction. Cannot be performed through MCP itself: a payment rides in an HTTP header and there is nowhere to put one here. This tool tells you the call; you make it.

Discovered
explain_qart

Explain how qart.uk works: scan verification, retargeting a printed code, the free claim pool and its daily allowances, Studio pricing, and what happens to credits when a run is stopped or fails. Use this before guessing at product details — pricing and allowances change and this returns the current text.

Discovered
get_credit_packs

What Studio credits cost: the packs on sale, their price in USD, and roughly how many images each buys. Anonymous — this is a price list. Read it rather than quoting a price from memory; packs change. An agent that runs out mid-task can top up WITHOUT a human, paying from its OWN wallet: POST /api/qart/x402/credits?pack=... with a qart:purchase bearer token. The money comes from the application's wallet, never the user's card. Stripe checkout (POST /api/qart/checkout) remains human-only; hand the user the purchase URL for that.

Discovered
get_dither_qr_parameters

The complete parameter contract for qart.uk's dithered photo QR recipe — an error-diffused technique (after andrew-t) that dithers a photograph into the space around each QR module, so the finished 1-bit image reads as a picture and still scans. THIS TOOL GENERATES NOTHING. There is no API for the technique and no endpoint that will run it for you: it is a browser-side generator, and this tool returns the parameters, ranges, defaults and algorithm order so that YOU can implement it or instruct someone who will. Pair it with get_qr_matrix, which supplies the module grid and the function-pattern map the algorithm needs. It also returns the honest limits, which matter before anyone prints anything: no scan verdict is computed anywhere in this path, error correction wants to stay at H, and stricter detectors (zbar) reject output that phone-grade detectors accept. Treat a dithered code as untested until someone scans the actual printed sheet.

Discovered
get_qr_matrix

Return the actual QR MODULE GRID for a payload — the black/white matrix, plus a per-module map of which modules are function patterns (finder, separator, timing, alignment, format info, version info, dark module) and which carry data. Both come back as one row string per row. Costs nothing, mints nothing, stores nothing. Use this when you are going to RENDER or transform a QR yourself: dithering a photo into it, drawing it as an SVG, laying it out for print, or reasoning about which modules are safe to alter. The function-pattern map is the point — any technique that paints over a QR has to know which modules a scanner uses to FIND the code (finder, timing, alignment) versus which merely carry bits. Do NOT use it to check whether a payload fits — preview_qr_encoding is smaller and answers that. Do NOT use it to get a qart.uk product: this is a plain standards QR, with no artwork, no scan verdict and no alias behind it. The matrix is canonical and untransformed: invert, rotation, mirror and any subpixel scaling are yours to apply afterwards.

Discovered
preview_qr_encoding

Work out how a payload will encode as a QR code, without creating anything. Returns the exact string the pixels would carry, its byte length, the QR version and module count required, the capacity remaining at that version, and any warnings. Costs nothing and mints nothing. Use this to answer questions like "will this URL fit at error correction level H" or "how much does a long Wi-Fi password cost me in QR density". Higher ECC survives damage better but needs more modules for the same data; more modules print smaller and get harder to scan. payloadKind 'qart_code' sizes the RETARGETABLE variant instead: the pixels carry a 16-byte qart.uk/_ link rather than your data, which is usually several versions smaller. Compare the two before committing to a print. This returns metadata only, never the module grid. For the actual black/white matrix, call get_qr_matrix.

Discovered
resolve_qart_code

Resolve a scanned qart.uk code to the URL it currently points at. Accepts the alias ('_ab12cde'), or a full qart.uk URL to pull it out of. Returns targetUrl, or disabledReason if the owner retired it. This does not count as a scan and will not affect the owner's statistics. Only the '_' code class resolves here; older qart.uk links of other shapes are not in this pool.

Discovered

Recent measurements

Probe history

View status
Latest stored probes. Raw probe rows are kept for 14 days.
CheckedResultResponseTools
Connected411 ms8