Zovo Palette Lab
REMOTE · CONTRAST-CHECKER.ZOVO.ONE
WCAG contrast & palettes
Available components
Last scanned (1 hour ago)
Scores higher than 66% of remote servers
Reachable. Last reached 23 Oct 2026.
Category Design and Media
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security80
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one. See how to fix → View diagnostics → Partial
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- The HSTS (Strict-Transport-Security) header is present. View diagnostics → Pass
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability74
- 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).Pass
- AI-judged instruction clarity (good).Pass
- Context-footprint check failed: tool/resource definitions use about 1102 tokens (~275/item across 4 items; 3 tools + 1 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management3
- Stability observed for 1 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
- Structured output schemas are declared (100% of tools); any adoption earns full credit.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 3 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 5 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
- Supports UI / widget rendering.Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 23 Oct 26 +1
- Stability: unverified → 0.03 ▲ functional
- 22 Oct 26 73
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 23 Oct 2026 · Probed https://contrast-checker.zovo.one/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=zovo.one | CN=WE1,O=Google Trust Services,C=US | 2 Oct 2026 | 31 Dec 2026 | ECDSA 256 | ECDSA-SHA256 | ebdf6403eac8ab2e0ec20a3bf36facb0 |
| SANs: zovo.one, contrast-checker.zovo.one, *.contrast-checker.zovo.one | ||||||
| CN=WE1,O=Google Trust Services,C=US (CA) | CN=GTS Root R4,O=Google Trust Services LLC,C=US | 13 Dec 2023 | 20 Feb 2029 | ECDSA 256 | ECDSA-SHA384 | 7ff31977972c224a76155d13b6d685e3 |
| CN=GTS Root R4,O=Google Trust Services LLC,C=US (CA) | CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE | 15 Nov 2023 | 28 Jan 2028 | ECDSA 384 | SHA256-RSA | 7fe530bf331343bedd821610493d8a1b |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of contrast-checker.zovo.one. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| one. | present | 64939 | 8 | Verified |
| zovo.one. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
| Header | Value |
|---|---|
| strict-transport-security | max-age=15552000; includeSubDomains; preload |
| x-content-type-options | nosniff |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://contrast-checker.zovo.one/mcp | Verified | 200 | |
| http (plaintext) | http://contrast-checker.zovo.one/mcp | HTTPS enforced | 301 | https://contrast-checker.zovo.one/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
check_color_contrast Check color contrast ~492
Use this when the user wants to know whether a text, icon or border colour has enough contrast against a background: a WCAG contrast checker for one colour pair (e.g. "does white text on #F59E0B pass WCAG AA", "contrast ratio of #767676 on white", "what text color for this background"). Returns the computed WCAG 2.x ratio (truncated to 2 decimals, rounded down), AA/AAA results for normal text, large text and UI components, a verdict for a given font size, APCA Lc as draft information, and the nearest passing colours for AA and AAA (darker and lighter, same OKLCH hue and chroma). Accepts hex, 8-digit hex with alpha, rgb(), hsl(), hwb(), lab(), lch(), oklab(), oklch(), color(display-p3 ...) and CSS colour names; wide-gamut colours are clipped to sRGB with a note. Does not read colours from images or web pages, resolve CSS variables or currentColor, or check gradients as a whole (check each stop). For 3 or more colours use check_palette_contrast.
| Name | Type | Req | Description |
|---|---|---|---|
| adjust | string | – | Which colour the suggested fixes change, e.g. foreground. auto (default) changes the more colourful of the two, so brand colours keep their hue. |
| background | string | yes | Background colour behind it, e.g. #FFFFFF, white or #1E293B. A translucent background is composited over white. |
| bold | boolean | – | Optional: true when that text is bold (font-weight 700+), e.g. true. Bold text from 18.66px counts as large text. |
| font_size_px | number | – | Optional text size in CSS pixels for a single verdict on that text, e.g. 16. 18pt = 24px; 14pt = about 18.66px. |
| foreground | string | yes | Text, icon or border colour, e.g. #767676, #1E6FD980 (8-digit hex with alpha), rgb(118, 118, 118), hsl(214 76% 48%), oklch(55% 0.18 255) or a CSS colour name such as navy. Translucent colours are com… |
| Name | Type | Req | Description |
|---|---|---|---|
| apca | object | yes | – |
| background | object | yes | – |
| fixes | object | yes | – |
| foreground | object | yes | – |
| kind | string | yes | – |
| ratio | number | yes | – |
| ratio_4dp | number | yes | – |
| request | object | yes | – |
| warnings | array | yes | – |
| wcag | object | yes | – |
| your_text | – | yes | – |
No examples provided.
check_palette_contrast Check palette contrast ~260
Use this when the user has a colour palette (2 to 12 colours) and wants to know which combinations are accessible: "check contrast of my color palette", "which of these colors can I use for text", "accessible color palette checker". Returns the full pairwise WCAG 2.x contrast matrix (ratios truncated, rounded down), which pairs pass AA/AAA for text or 3:1 for large text and UI, and a recommended text colour for each background (a palette colour that passes AA, otherwise black or white). Does not generate new colours; use generate_accessible_palette for a tonal scale and check_color_contrast for fixes to one pair.
| Name | Type | Req | Description |
|---|---|---|---|
| colors | array | yes | 2 to 12 colours to test against each other, e.g. ["#1E6FD9", "#F59E0B", "#FFFFFF", "#111827"]. Hex, rgb(), hsl(), hwb(), lab(), lch(), oklab(), oklch(), color(display-p3 ...) or CSS names; translucen… |
| names | array | – | Optional labels in the same order as colors, e.g. ["Primary", "Accent", "Surface", "Ink"]. |
| Name | Type | Req | Description |
|---|---|---|---|
| best_text | array | yes | – |
| colors | array | yes | – |
| kind | string | yes | – |
| matrix | array | yes | – |
| request | object | yes | – |
| summary | object | yes | – |
| text_pairs | array | yes | – |
| warnings | array | yes | – |
No examples provided.
generate_accessible_palette Generate accessible palette ~250
Use this when the user wants an accessible colour scale or palette built from one colour: "color palette generator from hex", "generate a 50-950 scale from #1E6FD9", "tailwind color palette generator", "accessible color palette for my website". Builds an 11-step 50-950 tonal scale in OKLCH with the base hue, where 50-400 pass AA with black text, 500 passes AA with both white and black text, 600 passes AA with white text and 700-950 pass AAA with white text, and each ratio is reported. Returns CSS custom properties and a Tailwind config as downloads. Does not pick colours by mood or brand meaning and does not extract palettes from images.
| Name | Type | Req | Description |
|---|---|---|---|
| base_color | string | yes | Brand or base colour to build the 50-950 scale from, e.g. #1E6FD9, rgb(30, 111, 217), oklch(55% 0.18 255) or teal. |
| name | string | – | Token name for CSS variables and the Tailwind colour key, e.g. brand (gives --brand-500). Default brand. |
| Name | Type | Req | Description |
|---|---|---|---|
| base | object | yes | – |
| css | string | yes | – |
| downloads | object | yes | – |
| kind | string | yes | – |
| name | string | yes | – |
| pairs | array | yes | – |
| request | object | yes | – |
| rules | array | yes | – |
| steps | array | yes | – |
| tailwind | string | yes | – |
| warnings | array | yes | – |
No examples provided.
How do I install the Zovo Palette Lab MCP server?
Zovo Palette Lab is a hosted endpoint at https://contrast-checker.zovo.one/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · contrast-checker.zovo.one
claude mcp add --transport http theluckystrike-contrast-checker 'https://contrast-checker.zovo.one/mcp'
What is the Zovo Palette Lab MCP server?
Zovo Palette Lab is an MCP server listed in the public MCP registry as io.github.theluckystrike/contrast-checker. WCAG contrast & palettes. This page covers its hosted endpoint (https://contrast-checker.zovo.one/mcp).
Is the Zovo Palette Lab MCP server safe to use?
Zovo Palette Lab scores 74 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Zovo Palette Lab MCP server expose?
Zovo Palette Lab exposes 3 tools: check_color_contrast, check_palette_contrast, generate_accessible_palette. Their descriptions and schemas cost roughly 1,002 tokens of context every time the server is loaded.
Does the Zovo Palette Lab MCP server require authentication?
No. We connected to Zovo Palette Lab without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the Zovo Palette Lab MCP server still maintained?
Zovo Palette Lab is still listed as active in the MCP registry. We last reached this channel on 23 October 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.