uxlint
Officialuxlint
Audita la UX de cualquier sitio web como lo haría un revisor con criterio de diseño: contraste, objetivos táctiles, escala tipográfica, disciplina cromática, patrones de escaneo, hitos. Cada hallazgo viene con una corrección prescriptiva que un agente (o un humano) puede aplicar directamente. Está diseñado para integrarse en el bucle de un agente de programación (MCP) e iterarse hasta que todo quede en verde.

Una ejecución real, de principio a fin: audit_url → Grade B, un error de contraste de 2.39:1 y tres CTA en tres tonos de acento distintos → la corrección → verify_fix → Grade A. Cada número proviene de las herramientas; solo se ha recortado la espera.
Este es el CLI: un único binario estático de Rust. Controla un Chrome/Chromium que ya tengas instalado mediante el protocolo DevTools (sin Node, sin Playwright, sin descarga de navegador headless), captura cómo se ve y se lee una página y envía eso al servidor alojado de uxlint, que es quien hace la calificación real. El motor de reglas, los umbrales calibrados y el juez LLM viven en el servidor, por lo que el cliente nunca necesita actualizarse cuando cambia una regla.
┌──────────────────────────┐ POST /v1/audit {snapshots} ┌──────────────────────────┐
│ uxlint (this binary) │ ───────────────────────────────────────▶ │ uxlint-server (hosted) │
│ drives YOUR Chrome (CDP) │ ◀─────────────────────────────────────── │ rules engine + LLM judge │
└──────────────────────────┘ report {findings + fixes} └──────────────────────────┘Instalación
curl -fsSL https://uxlint.net/install.sh | sh # detects OS/arch, verifies checksumO con mise: su backend github descarga la compilación correspondiente desde GitHub Releases, la verifica y se actualiza con mise up:
mise use -g "github:uxlint-net/uxlint-cli[rename_exe=uxlint]@latest"o fíjalo en el mise.toml de un proyecto:
[tools]
"github:uxlint-net/uxlint-cli" = { version = "latest", rename_exe = "uxlint" }O compila desde el código fuente (necesita una toolchain de Rust estable reciente y un Chrome/Chromium en el PATH):
git clone https://github.com/uxlint-net/uxlint-cli && cd uxlint-cli
cargo build --release
./target/release/uxlint --versionRelated MCP server: Prufa
Inicio rápido
uxlint auth login # opens your browser, saves a token
uxlint audit --base https://your-site.com --routes /,/pricing¿Es la primera vez que auditas tu propio proyecto? uxlint init elige (o crea) un sitio al que adjuntar los informes y escribe un uxlint.toml para que cualquier auditoría futura en este directorio funcione directamente:
uxlint init
uxlint audit --base http://localhost:5173 --routes /,/pricingCódigo de salida 1 ante hallazgos por encima de la severidad configurada → introdúcelo directamente en CI (consulta .github/workflows/ para ver una plantilla, o la GitHub Action uxlint-net/uxlint-action).
Ocultar elementos de una auditoría (uxlint-hide)
Algunos elementos de la interfaz de la página no son producto y no deberían evaluarse: un banner de entorno de desarrollo/staging, un marcador «DEV», una barra de depuración, un elemento de Storybook/vista previa. Añade la clase uxlint-hide a cualquier elemento de este tipo y la auditoría lo elimina: es display:none desde el primer renderizado, por lo que nunca aparece en una captura de pantalla y es invisible para el recopilador (no genera ningún hallazgo):
<div class="env-banner uxlint-hide">STAGING</div>La clase es inerte en tu sitio real: no hace nada a menos que la auditoría esté en ejecución, porque la hoja de estilos que la oculta (.uxlint-hide { display: none !important; }) solo la inyecta el navegador de uxlint, antes de que se ejecuten los scripts de la propia página. Puedes estilizar tu elemento como quieras el resto del tiempo. Se aplica en todas las rutas de captura: el rastreo, las pruebas de recorrido por objetivos y las vistas previas de correcciones.
MCP (úsalo desde un agente de programación)
Claude Code, un comando:
/plugin marketplace add uxlint-net/uxlint-cli
/plugin install uxlint@uxlintEso instala el servidor MCP de uxlint y, si el CLI aún no está en tu PATH, descarga la versión correspondiente una sola vez con el mismo instalador que verifica checksums descrito arriba, de modo que /plugin update actualiza también el CLI subyacente. No se necesita Node: descarga un único binario estático (verificado contra un checksum publicado) y controla el Chrome que ya tienes.
Cualquier otro agente, con una línea (el paquete npm descarga el binario para tu plataforma, verifica el checksum publicado junto a él y te lo entrega). Esta es la única ruta que necesita Node 18+, por el propio npx; si prefieres no usarlo, instala el binario con la línea de arriba y regístralo así:
claude mcp add uxlint -- npx -y @uxlint-net/uxlint mcpO, para un cliente que lea una configuración JSON:
{ "mcpServers": { "uxlint": { "command": "npx", "args": ["-y", "@uxlint-net/uxlint", "mcp"] } } }uxlint también está en el MCP Registry como io.github.uxlint-net/uxlint, para clientes que lo exploran. ¿Ya tienes el CLI? uxlint mcp install lo registra directamente, sin envoltorio de npx.
No hay ningún token que configurar primero: pídele a tu agente que audite algo sin haber iniciado sesión y te dará un enlace de inicio de sesión que emite y guarda el token por ti (UXLINT_API_KEY es para CI, que no tiene navegador).
Cinco herramientas: audit_url (auditoría completa, veredicto con calificación + plan de acción), verify_fix (vuelve a revisar una regla en una página después de una edición, ~2s), get_shot (obtiene la captura de pantalla anotada de un hallazgo), ux_guidance (orientación de mejores prácticas para leer antes de construir la UI) y lint_feedback, opcional y desactivada por defecto (§ Privacidad), una herramienta para tres tipos de señal: si un hallazgo fue útil, si falta un lint en uxlint o si hay una biblioteca de componentes que no reconoció. El agente audita, lee las correcciones, edita y vuelve a auditar hasta que todo quede en verde.
Privacidad y confianza
Este CLI se ejecuta en tu máquina y controla un navegador real contra páginas reales, por lo que es justo preguntar exactamente qué captura y a dónde va. Lo que podemos decirte, porque es lo que realmente hace el código de este repositorio:
El recopilador está integrado y es legible. Está compilado dentro de este binario (
include_str!deassets/collector.js), por lo queuxlint --versionfija el código de captura exacto y el servidor no puede inyectar nada en tiempo de ejecución. Todo lo que captura es geometría de la página, texto visible, estilos calculados y capturas de pantalla. Para un<iframe>embebido registra solo el host del src, nunca la URL de embebido completa, que puede llevar identificadores de sesión y tokens en su query string. Nunca lee tu código fuente ni tu sistema de archivos más allá deuxlint.toml. Sí lee un poco de procedencia del proyecto y lo envía con el informe: el sha de tu commit git actual y el nombre de la rama (git rev-parse), el hostname de la máquina y, en GitHub Actions, el enlace al repo/PR/commit. ConfiguraUXLINT_RUNNERpara sobrescribir el hostname.El enmascarado de secretos y PII se hace con el mejor esfuerzo, no es una garantía. Antes de subir nada, el recopilador enmascara el texto que parece un token, una clave de API, una contraseña o una dirección de correo electrónico en el texto capturado de la página, y aplica los mismos patrones de enmascarado a los registros de consola y a los mensajes de diálogo nativos. Todos los canales comparten una única lista de patrones (
assets/redact.js), de modo que no pueden desincronizarse. Las capturas de pantalla reciben una pasada adicional justo antes de la captura: el valor de cada campo de formulario se enmascara (las contraseñas se dejan en blanco, los demás campos se sustituyen por puntos) y los secretos que coinciden con patrones en el texto de la página se eliminan, para que los datos escritos y las claves mostradas no acaben en la imagen. Esa pasada llega al shadow DOM (incluidas las raíces cerradas, mediante un interceptor deattachShadow) y a los iframes del mismo origen, y cubre un iframe de origen cruzado con una caja opaca, ya que sus píxeles no se pueden enmascarar. Pero el enmascarado se basa en patrones, y una captura de pantalla sigue siendo píxeles: el contenido mostrado arbitrario que ningún patrón detecta (un nombre de cliente en la página, datos de un pedido), los valores fragmentados y cualquier cosa dibujada en imágenes o en<canvas>pueden colarse igualmente. Las credenciales que pases con--header/--storage/--login-*controlan tu navegador únicamente y nunca se envían al servidor de uxlint.Debido a que un informe captura el HTML de la página, el texto y las capturas de pantalla, es imposible protegerlo por completo contra la filtración de contenido sensible. Usa cuentas TEST, no reales ni de producción. Para el desarrollo local, el riesgo es bajo, siempre que los datos sean solo datos de desarrollo local. Cuando audites un sitio autenticado que contenga secretos reales o datos personales, revisa lo que se envía antes de enviarlo: usa
--dry-runpara escribir la carga exacta (texto de la página, procedencia y capturas de pantalla) en una carpeta local e inspecciónala sin subirla. El enmascarado reduce la exposición accidental; no es una frontera de seguridad, y tú sigues siendo responsable de a qué apuntes uxlint.**El texto de navegación se limpia solo de secret
Available Tools
6 toolsacknowledge_findingA
Mark ONE finding as a known false positive for this site, so later audits stop counting it — it moves out of the findings, the counts and the grade into the report's acknowledged list, where it stays visible with your reason. Use it only after you've checked the finding is wrong on this page (the rule misread it), never to silence a real problem you'd rather not fix. Pass the report (URL or id), the rule and the selector exactly as the finding gives them, and a reason. undo=true puts it back. Works on reports filed under a site.
| Name | Required | Description | Default |
|---|---|---|---|
| rule | Yes | The finding's rule, exactly as the report names it. | |
| undo | No | true to withdraw an earlier acknowledgement, putting the finding back. | |
| reason | No | Why the finding is wrong HERE — shown beside it in every later report, so whoever reads the report can see why it isn't counted. Required to acknowledge (20+ characters); not needed to undo. | |
| report | Yes | The report the finding is in: its URL (…/r/<id>) or its id. | |
| selector | No | The finding's selector (`selector` in the structured result); `site` for a site-wide finding. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the full disclosure burden, and it does so well: it explains the state transition (out of findings, counts and grade), persistence in the `acknowledged` list 'where it stays visible with your reason', and the reversal mechanism ('undo=true puts it back'). It also notes the site-scoping constraint ('Works on reports filed under a site'). It does not mention permissions/authorization or idempotency of repeat acknowledgements, keeping it below 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Front-loads the core action and effect in the first sentence, then adds usage guidance, parameter passing, and undo in a tight sequence. Every sentence is functional, though the em-dash-heavy compound sentences and the trailing site-scoping note reduce crispness slightly.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a mutation tool with no annotations and no output schema, the description covers purpose, effect, usage constraints, and reversal, which is close to what an agent needs. It omits the response shape and whether the report must be a site report in all cases beyond the terse 'Works on reports filed under a site' note.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100% and every parameter (report, rule, selector, reason, undo) is documented in the schema itself, so the baseline is 3. The description mostly restates that set ('Pass the report (URL or id), the rule and the selector exactly as the finding gives them, and a reason') with only slight added guidance about copying values verbatim from the finding.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource ('Mark ONE finding as a known false positive for this site') and immediately describes the downstream effect on findings, counts, grade, and the acknowledged list. This is unmistakably distinct from audit_url, get_report, get_shot, and verify_fix without opening any schema.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Gives an explicit precondition ('only after you've checked the finding is wrong on this page (the rule misread it)') and an explicit exclusion ('never to silence a real problem you'd rather not fix'), which is strong when/when-not guidance. It does not name an alternative tool (e.g. verify_fix) for the case where the problem is real, so it stops short of full 5-level routing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
audit_urlA
Audit a website's UX/design: contrast, tap targets, type scale, colour discipline, copy clarity, scan patterns. Each finding returns its RULE name (pass it to verify_fix), a SOURCE file:line hint (for local audits, grepped from the project you're in), the SELECTOR, the concrete FIX, and — for copy issues — the exact text EDIT (replace X with Y).
WORKFLOW: (1) Before you change anything, call ux_guidance for the area(s) the findings touch (forms, lists, layout, copy, …) so you fix toward the idiomatic, DRY pattern — not a one-off patch. If the result names a STYLEGUIDE, open it first and build to the components/tokens it shows. (2) Open the source line and apply the SMALLEST fix that reuses the project's existing components/tokens and voice (don't add a new one-off to silence the finding) without regressing the quality floor — responsive, visible keyboard focus, reduced motion, no new layout shift — then verify_fix. (3) Iterate until green. A finding you've checked and found WRONG on this page (the rule misread it)? acknowledge_finding marks it a known false positive for the site, so it stops coming back and stops counting against the grade — it stays visible in the report, with your reason. If a lint_feedback tool is in your tool list, also send a verdict for each finding you act on — it's how rules get kept, tuned or retired. It is absent unless the project set feedback = true (via uxlint init), so don't go looking for it: this result tells you when it's there.
SAFETY: interaction probes navigate, read, and click candidate menu/disclosure/dialog controls. Discovery skips recognised action words — delete, remove, accept, leave, revoke, pay, publish, add, create, save — using the full label. Labels cannot guarantee a click has no side effects; use an environment you control with disposable data. the write probes (which click Add/Create, and Delete through its confirm dialog) need the CLI's own --allow-mutation flag, which is not reachable from here. Declared tests are the exception and the only one: if the project's uxlint.toml declares tests that sign in as a persona, running them will SUBMIT forms and may DELETE items — that's what a test does, and it exercises create/delete flows on your own app. Point it only at an app you own / a throwaway env, never a site you don't control.
SETUP: in a project with no uxlint.toml, this returns the exact config to write first (org/site/base/routes) — write that file, check it in, then call again. Without it a local target can't be audited at all and a public one files its report under a site nobody chose.
AUTH: for a logged-in site, DON'T pass secrets here — credentials come from the project's uxlint.toml [personas] (the local client replays them; nothing touches this tool call or the transcript). If the audit hits a login wall, this tool returns the exact setup instructions.
| Name | Required | Description | Default |
|---|---|---|---|
| base | No | Base URL to audit — an ORIGIN like http://localhost:5173, NOT a path (a path gets appended to every route and mis-crawls). Optional: omit to use the `base` in the project's uxlint.toml. | |
| crawl | No | Max routes to discover and audit from the seeds (default 12). Set 0 to audit only the given routes. | |
| judge | No | Run the AI copy/design judge (prose quality, test-run navigation). ON by default; set false for a fast, deterministic-only pass while iterating. | |
| tests | No | Run the site's declared tests (whole-site reachability). ON by default; auto-scoped to crawling audits. Set false to skip for speed. Tests are a paid-plan feature — on a free plan, tests declared but not run print a one-line skip warning instead. | |
| detail | No | `full` for every finding's fix, best practice, rect and screenshot URL in the structured result. Default is compact: every finding, with each rule's fix said once — the full form can run past a client's output limit on a big site. | |
| routes | No | Comma-separated routes (default /) | |
| states | No | Drive hover/focus/keyboard interaction states — catches dead hover styles, hover-only content unreachable by touch/keyboard, illogical focus order, keyboard traps, form-validation gaps. ON by default; set false to skip it (faster) on large public crawls. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden and does so: it discloses that interaction probes navigate/read/click, that discovery skips action-word labels, that write probes need an unreachable --allow-mutation flag, that declared tests SUBMIT forms and may DELETE items, and that credentials come from uxlint.toml personas. Mutation and side-effect risks are stated plainly.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
It is long, but it is organized into labelled WORKFLOW/SAFETY/SETUP/AUTH blocks with the purpose and return shape front-loaded, and each block carries decision-relevant content rather than filler. A few sentences could be tightened, but nothing is redundant.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a 7-parameter, zero-annotation tool with mutation-capable probes, no output schema, and a setup prerequisite, the description covers return shape, workflow, safety, auth, and setup. Nothing an agent needs to invoke it correctly is missing.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100%, so the schema already documents base, crawl, judge, tests, detail, routes, and states with defaults and constraints. The description adds output-format detail (RULE, SOURCE file:line, SELECTOR, FIX, EDIT) but little beyond the schema on the parameters themselves, so baseline 3 applies.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Opens with a specific verb+resource ('Audit a website's UX/design') and enumerates the concrete dimensions checked (contrast, tap targets, type scale, copy clarity). It also describes the shape of each finding and explicitly routes to siblings (verify_fix, ux_guidance, acknowledge_finding), so the agent can distinguish it from the rest of the toolset.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Provides an explicit numbered WORKFLOW with when-to-do-what ordering (ux_guidance before changes, open source line, smallest fix, verify_fix, iterate), plus the acknowledge_finding escape hatch for false positives and the conditional lint_feedback path. Alternatives and their triggering conditions are named rather than implied.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_reportA
Read an EXISTING report's findings — one the user started from the dashboard, a run whose audit_url call you lost, or one that TIMED OUT (it keeps whatever it found before the cap, and says so). Pass the report's URL as the user sees it (…/r/) or its id. Returns the same thing audit_url does: the grade, what moved since the last run, and every finding with its rule, location, source hint, fix and screenshot_url — so you can act on it and confirm each fix with verify_fix. Reports are private; this reads them with your uxlint login.
| Name | Required | Description | Default |
|---|---|---|---|
| detail | No | `full` for every finding's fix, best practice, rect and screenshot URL in the structured result; compact by default (see audit_url). | |
| report | Yes | The report to read: its URL as the dashboard shows it (`https://uxlint.net/sites/8/r/abc123`), a `/r/…` path, or the bare report id. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the full burden, and it delivers: it labels the operation as a read, discloses that timed-out reports preserve partial findings and say so, and notes reports are private and read with the user's uxlint login. It also commits to a stable output shape by enumerating the returned fields.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is front-loaded with the core purpose, and each sentence adds a distinct fact: use cases, input formats, return payload, and privacy/auth. It is longer than minimal but dense and without filler, though the parenthetical examples could be slightly tightened.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
With no output schema, the description compensates by enumerating the returned grade, deltas, and each finding's fields, and by explaining timeout behavior and auth requirements. It does not cover error cases or exact formatting, but the schema handles parameter formatting, making this complete enough for correct invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema already documents both parameters with 100% coverage, so the baseline is 3. The description restates the report parameter's accepted URL/path/id forms but adds no new semantic detail beyond the schema; detail's full-vs-compact behavior is delegated to audit_url and already covered in the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description opens with a specific verb-resource pair ('Read an EXISTING report's findings') and immediately distinguishes the tool from siblings by mentioning audit_url and verify_fix. It makes the scope explicit: existing reports, including timed-out ones, not new audits.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
It clearly identifies when to use get_report: reports started in the dashboard, lost audit_url calls, or timed-out runs. It does not explicitly say 'use audit_url for new audits', but 'EXISTING' and the audit_url reference make the boundary inferable, giving clear context without a formal when-not clause.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
get_shotA
View a report's annotated screenshot — the flagged element boxed on its page. Reports are PRIVATE, so a finding's screenshot_url can't be fetched with a plain GET; this tool fetches it with your uxlint login. Pass the finding's screenshot_url (from audit_url / verify_fix). Returns the image inline (if your client renders MCP images) and always writes it to a local file whose path you can open/Read.
| Name | Required | Description | Default |
|---|---|---|---|
| screenshot_url | Yes | The `screenshot_url` from an audit_url / verify_fix finding — the annotated shot with the flagged element boxed. A full URL or a `/r/…` path on your uxlint server. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries full burden. It discloses that reports are PRIVATE, reads requires the user's uxlint login, returns image inline (if client supports MCP images), and always writes to a local file. This adds significant behavioral context beyond what an annotation might provide, such as side effects (writing a file) and authentication requirements. The only minor gap is not detailing the exact file path or cleanup behavior, but the description is quite transparent.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is concise (about 3 sentences) and front-loads the core action. Every sentence provides essential information: purpose, why it's needed, what to pass, and what happens. No fluff or redundancy. The structure is logical: what, why, how, outcome.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given that there is only one parameter, no output schema, and no annotations, the description is complete. It covers the tool's purpose, usage, parameter source, return behavior (inline and local file), and the limitation about private reports. This is sufficient for an agent to select and correctly invoke the tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100% and it already explains the screenshot_url parameter clearly. The description adds contextual meaning by tying the parameter to the finding's screenshot_url and specifying the source (audit_url/verify_fix). It also clarifies that the URL can be a full URL or a /r/… path. This adds value beyond the schema, so a slightly above baseline score is warranted.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool's purpose: to view a report's annotated screenshot, with the flagged element boxed. It also distinguishes it from siblings by explaining why a plain GET won't work and that it requires the finding's screenshot_url. The verb 'View' and specific resource 'report's annotated screenshot' are precise.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly explains when to use this tool (to fetch a screenshot_url from audit_url/verify_fix findings) and why it's necessary (reports are private, plain GET won't work). It also provides context that the screenshot URL comes from specific sources, serving as an alternative to direct fetching. This is exactly the kind of usage guidance expected.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
ux_guidanceA
Project design memory and best-practice UI guidance to read BEFORE building or changing UI — usability, consistency, and performance patterns distilled from uxlint's audit corpus, so you build idiomatic, DRY, testable components the first time instead of getting audited after. Reads the nearest project’s uxlint.design.json on each call; only explicitly approved versioned decisions guide edits. Never auto-approve or rewrite that contract to silence a lint. Covers whole-row click targets, single-column labelled forms, tabs/radiogroup vs plain buttons, one shared width scale + aligned panels, pagination by scroll length, CLS-safe layout, copy that reads as UI (active voice, honest labels, useful empty/error states), and money surfaces (plans, usage, the cost of an action shown before it runs, failed payments). Each item names the uxlint rule that catches a miss, so the loop is: read the topic, build to it, then audit_url to confirm.
| Name | Required | Description | Default |
|---|---|---|---|
| topic | No | Which area to get guidance for: layout, forms, lists, navigation, components, performance, accessibility, content, money (plans, checkout, usage, cost before an action). Omit for the index of topics; "all" for everything. Accepts aliases (copy, nav, a11y, perf, dry, …) and falls back to the index for anything unrecognized. |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral load and does so well: it re-reads the nearest project's uxlint.design.json on each call, only approved versioned decisions steer edits, and it never auto-approves or rewrites the contract. The implicit read-only nature is conveyed rather than stated outright, but the governance constraints are unusually explicit for a retrieval tool.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The governing instruction (read before building) is front-loaded in the first clause, and the closing loop sentence ties usage together. It is on the long side and the enumerated topic catalogue slightly pad it, but every sentence carries operational information.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
No output schema exists, so the description must characterize returns, and it does: guidance items each name the uxlint rule that catches a miss. Combined with the read-before-build workflow and the config source, an agent has enough to invoke and interpret it. Return format granularity (single topic vs index) is only implied by the topic parameter.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% and the single topic parameter is fully documented in the schema, including the alias and fallback behavior, so the schema does the heavy lifting. The description's topic list largely restates the schema enum values and adds little parameter-level meaning beyond the schema itself. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb+resource (read UI/design guidance before building or changing UI) sourced from uxlint's audit corpus and the project's uxlint.design.json. It also distinguishes itself from siblings by defining the loop that terminates in audit_url. An agent can tell exactly what this tool returns versus audit_url or get_report.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly says to read BEFORE building or changing UI, names the alternative audit_url as the confirmation step after building, and states the exclusions: only explicitly approved versioned decisions guide edits, and never auto-approve or rewrite the contract. When-to-use, when-not, and the sibling handoff are all present.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
verify_fixA
After editing to fix a finding, re-check ONE rule on ONE page — the 'did my fix land?' loop, far quicker than a full re-audit (one route, no crawl, no judge). Returns whether the rule still fires, AND names any OTHER deterministic findings now on that page (the regression guard — so a fix that clears your rule but breaks something else here doesn't read as all-clear). Returns status passed, failed, not_evaluated or inconclusive. A pass requires explicit server evidence for the requested route and both viewports. Currently supported passing checks: page-title-missing, html-lang-missing, horizontal-overflow. Other rules can report observed failures but cannot pass without execution evidence; re-run audit_url for judge, interaction and site checks. Unknown rules and missing evidence never clear. A cleared finding is not a user endorsement of the fix.
| Name | Required | Description | Default |
|---|---|---|---|
| base | No | Base URL — an ORIGIN like http://localhost:5173, NOT a path. Optional: omit to use the `base` in the project's uxlint.toml. | |
| rule | Yes | The rule to verify is gone, e.g. contrast, tap-target, unlabelled-field | |
| route | No | The route to check, e.g. /pricing (default /) | |
| states | No | Drive interaction states (needed for state/form/interaction rules) |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It does a good job: discloses that the tool only reports observed failures for rules not in the supported passing list, that unknown rules and missing evidence never clear, and that a cleared finding is not a user endorsement of the fix. It also explains the regression guard behavior. It does not explicitly state whether the operation is read-only or has side effects, but given the described behavior (a check), this is implicit. One might argue for a 5, but the lack of explicit mention of side-effect-freeness or any destructive potential is a tiny gap; still, it's quite thorough.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is a solid paragraph, slightly long but information-dense. It front-loads the purpose, then adds critical caveats. It could be split into bullet points for readability, but every sentence earns its place — no filler. The length is justified given the complexity (supported rules, evidential requirements, regression guard, exclusions).
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a tool with no output schema and no annotations, the description does an excellent job of covering everything an agent needs: what it does, when to use it, what the return statuses mean, what constitutes a pass (explicit server evidence for the requested route and both viewports), which rules are supported for passing, what happens for other rules, and how to handle judge/interaction/site checks. It also mentions the regression guard, covering the risk of a fix breaking something else. Very complete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so the schema already documents all four parameters. The description adds context about the rule parameter (which rules are supported for passing) and hints at the interaction states for state/form/interaction rules, but does not add substantial new semantics beyond what's in the schema. The description does not mention default values or relationships that are not already present in the schema. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states the specific verb ('re-check'), resource ('ONE rule on ONE page'), and purpose ('did my fix land?'). It clearly distinguishes itself from a full re-audit by naming the alternative (audit_url) and explaining the difference (one route, no crawl, no judge). The description is not a tautology; it explains the tool's role in the fix-verify workflow.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explicitly states when to use this tool (after editing to fix a finding, to verify a specific fix) and when not to use it (for judge, interaction and site checks — says to re-run audit_url for those). It also names the sibling tool audit_url as the alternative. It provides clear conditions: a pass requires explicit server evidence for the requested route and both viewports, and unsupported rules cannot pass. This is explicit and actionable.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
2 tool updates
v0.1.46- Added
acknowledge_finding - Changed
ux_guidance1 field changed- changed
Input schema / properties / topic / descriptionPrevious value: -"Which area to get guidance for: layout, forms, lists, navigation, components, performance,\naccessibility, content. Omit for the index of topics; \"all\" for everything. Accepts aliases\n(copy, nav, a11y, perf, dry, …) and falls back to the index for anything unrecognized."New value: +"Which area to get guidance for: layout, forms, lists, navigation, components, performance,\naccessibility, content, money (plans, checkout, usage, cost before an action). Omit for the\nindex of topics; \"all\" for everything. Accepts aliases\n(copy, nav, a11y, perf, dry, …) and falls back to the index for anything unrecognized."
2 tool updates
v0.1.41- Changed
audit_url1 field changed- added
Input schema / properties / detailAdded value: +{ + "default": null, + "description": "`full` for every finding's fix, best practice, rect and screenshot URL in the structured\nresult. Default is compact: every finding, with each rule's fix said once — the full form can\nrun past a client's output limit on a big site.", + "type": [ + "string", + "null" + ] +}
- Added
get_report
4 tool updates
- First observed
audit_url - First observed
get_shot - First observed
ux_guidance - First observed
verify_fix
TDQS
Scored across 6 tools
Each tool has a distinct role in the audit workflow: running audits, reading reports, viewing screenshots, verifying fixes, acknowledging findings, and getting design guidance. While audit_url and get_report both surface findings, one initiates a run and the other retrieves an existing one, and the descriptions make this boundary clear. No two tools appear interchangeable.
Most tools follow a verb_noun pattern (acknowledge_finding, get_report, get_shot, verify_fix), with audit_url fitting the same style. The sole deviation is ux_guidance, a noun phrase with a ux_ prefix, which breaks the pattern slightly but remains readable and unambiguous.
Six tools cleanly cover the core loop of guidance, audit, inspect, verify, and acknowledge. Nothing feels redundant or missing at this scale, and the set is well-scoped for a focused UX linting server.
The surface covers the main lifecycle: read guidance, run an audit, retrieve reports, view evidence, verify individual fixes, and acknowledge false positives. A list_reports tool for discovering existing report IDs without already having a URL is a minor missing convenience, but most workflows are fully supported.
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