Servidor MCP que permite a los asistentes de IA obtener contenido de páginas web autenticadas.
Cuando tu IA intenta leer una URL que requiere inicio de sesión, esta herramienta abre un navegador real para que inicies sesión, y luego captura el contenido de la página como HTML limpio. Las sesiones se guardan localmente, por lo que solo inicias sesión una vez por servicio.
Related MCP server: byob
claude mcp add --scope user auth-fetch -- npx auth-fetch-mcp@latest{
"mcpServers": {
"auth-fetch": {
"command": "npx",
"args": ["auth-fetch-mcp@latest"]
}
}
}Chromium se instala automáticamente en la primera ejecución si no está presente.
Pide a tu IA que lea cualquier página autenticada; simplemente pega la URL.
Se abre una ventana del navegador automáticamente y navega a la página.
Inicia sesión como lo harías normalmente (admite SSO, 2FA, CAPTCHA, cualquier cosa).
Haz clic en el botón "📸 Capture" en la esquina inferior derecha cuando estés listo.
El contenido de la página se captura como HTML limpio (se eliminan los elementos de ruido, se conservan las etiquetas multimedia), el navegador se cierra y tu IA recibe el contenido.
auth_fetchLa herramienta principal. Obtiene el contenido de la página usando un navegador real, abriendo una ventana para iniciar sesión si es necesario. Devuelve HTML limpio con los elementos de ruido (navegación, pie de página, scripts, etc.) eliminados y las etiquetas multimedia (<img>, <video>, <iframe>) conservadas.
Parámetro | Tipo | Requerido | Descripción |
| string | sí | La URL de la cual obtener el contenido |
| string | no | Selector CSS para esperar antes de capturar (útil para SPAs) |
download_mediaDescarga archivos desde URLs usando sesiones de navegador guardadas. Úsalo para descargar de forma diferida imágenes, videos u otros archivos encontrados en los resultados de auth_fetch. Las cookies guardadas del navegador manejan la autenticación automáticamente; no es necesario volver a iniciar sesión.
Parámetro | Tipo | Requerido | Descripción |
| string[] | sí | Una o más URLs para descargar |
| string | no | Directorio donde guardar los archivos (por defecto |
Flujo de ejemplo:
1. auth_fetch("https://notion.so/my-page")
→ Returns HTML with <img src="https://s3.notion.so/signed-url..."/> tags
2. AI reads the HTML, identifies an image it needs
3. download_media(["https://s3.notion.so/signed-url..."])
→ Downloads the image using saved session cookies
→ Returns { localPath: "~/.auth-fetch-mcp/downloads/.../file-1.png" }list_pagesEnumera todas las pestañas abiertas en el navegador con sus URLs y títulos.
close_browserCierra la ventana del navegador. Las sesiones de inicio de sesión se guardan y se reutilizarán la próxima vez.
Todos los datos se almacenan localmente en ~/.auth-fetch-mcp/. No se envía nada a servidores externos.
Qué | Dónde | Cuándo | ¿Persistente? |
Sesiones de navegador (cookies, almacenamiento local) |
| Después del primer inicio de sesión | Sí — reutilizado tras reinicios |
Archivos multimedia descargados |
| Solo cuando se llama a | Sí — permanece hasta que lo elimines |
Contenido de página capturado (HTML) | No se guarda en disco | Se pasa directamente a la IA vía stdio | No — existe solo en el contexto de la IA |
Para borrar todos los datos:
# Clear login sessions only
rm -rf ~/.auth-fetch-mcp/browser-data/
# Clear downloaded files only
rm -rf ~/.auth-fetch-mcp/downloads/
# Clear everything
rm -rf ~/.auth-fetch-mcp/Claude Code
Cursor
Windsurf
Cualquier cliente compatible con MCP que use transporte stdio
Requiere un entorno local (no funciona en interfaces de chat basadas en web)
El primer acceso a cada servicio requiere inicio de sesión manual
Las páginas muy largas se truncan para ajustarse a las ventanas de contexto de LLM (100K caracteres)
Algunos sitios con detección de bots agresiva pueden no funcionar (prueba la opción wait_for)
Todos los datos permanecen en tu máquina; no se envía nada a servidores externos
El HTML capturado nunca se escribe en el disco; solo pasa a través de la tubería stdio a la herramienta de IA
Las sesiones del navegador se almacenan localmente como un perfil estándar de Chromium
Los archivos descargados van a un directorio local que tú controlas
¡Las contribuciones son bienvenidas! Por favor, abre un issue o envía un pull request.
git clone https://github.com/ymw0407/auth-fetch-mcp.git
cd auth-fetch-mcp
npm install
npm run buildMIT
Read a login-protected page using a local browser and human-approved capture. Use for authenticated pages or when normal web reading returns a login screen or empty content. Tell the user to sign in and click Capture page before calling. Returns a loaded-DOM snapshot, source URL, time, links, media and completeness warnings. Prefer format=text for reading; html preserves markup. Canvas, frame contents and unloaded content are not extracted. This call waits for the user.
| Name | Required | Description | Default |
|---|---|---|---|
| url | Yes | The URL to fetch content from | |
| format | No | Defaults to readable text. Select html when markup is needed. | text |
| wait_for | No | CSS selector that must be visible after the user captures. A missing selector returns an error. | |
| max_chars | No | Maximum returned content characters. Defaults to 20000; check truncated. | |
| timeout_seconds | No | Time allowed for manual login and Capture page. Configure the client's tool timeout to be longer. |
| Name | Required | Description |
|---|---|---|
| url | Yes | |
| links | Yes | |
| media | Yes | |
| title | Yes | |
| format | Yes | |
| status | Yes | |
| content | Yes | |
| warnings | Yes | |
| truncated | Yes | |
| captured_at | Yes | |
| links_truncated | Yes | |
| media_truncated | Yes | |
| original_length | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Goes well beyond the annotations by disclosing that the call blocks waiting on a human, that a missing wait_for selector errors, and that canvas, frame contents and unloaded content are not extracted. It also explains why readOnlyHint=false despite this being a read: it drives a real browser session and depends on user interaction.
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-loaded with purpose, then precondition, then return shape, then limitations. Every sentence carries distinct information with no padding.
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?
Covers the items an agent cannot infer: the human-in-the-loop requirement, the blocking wait, timeout mismatch advice, and extraction gaps. With an output schema present, it need not spell out return fields, though its brief summary of returns is a bonus.
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 all five parameters are already documented with defaults and constraints. The description's 'Prefer format=text for reading; html preserves markup' largely restates the enum descriptions rather than adding syntax or behavior the schema lacks.
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 ('Read a login-protected page') plus the mechanism ('local browser and human-approved capture'). This is clearly distinguishable from siblings like download_media, list_pages and close_browser, which do not read page content.
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 trigger ('Use for authenticated pages or when normal web reading returns a login screen or empty content') and a concrete precondition workflow ('Tell the user to sign in and click Capture page before calling'). It does not name an alternative tool by name, so it stops just short of a 5.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Close the browser when the user asks to cancel. An active capture will fail; saved login sessions are retained. Do not call during capture unless cancellation is intended.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
| Name | Required | Description |
|---|---|---|
| message | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the annotations, it discloses the key side effect (an active capture will fail) and the state that survives (saved login sessions are retained), plus the operational constraint about not closing mid-capture. This is precisely the behavioral context annotations cannot convey, and it does not conflict with destructiveHint=false since no persisted data is destroyed.
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?
Three short sentences, front-loaded with the primary action and followed by the side effect and the guardrail. Every sentence carries distinct information with no redundancy.
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 zero-parameter session-control tool with an output schema and full annotation coverage, the description supplies the trigger, the failure mode, and the persistence behavior. 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?
The tool takes zero parameters, so the baseline is 4 and there is nothing for the description to disambiguate. It correctly implies the operation is unconditional on input.
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 a specific verb and resource ('Close the browser') and ties it to a user intent ('when the user asks to cancel'), so the action is unambiguous. It does not explicitly distinguish itself from the sibling tools, though none of them offer an overlapping close-session capability, so the gap is minor.
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 gives an explicit trigger ('when the user asks to cancel') and an explicit exclusion ('Do not call during capture unless cancellation is intended'), which is exactly the when/when-not guidance an agent needs. No alternative tool competes for this action, so no further routing is required.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Download only attachments needed for the user's task using saved browser cookies. Returns local paths, sizes, and per-file errors. Check downloaded before reporting success. Cookies may not cover sites that require JavaScript-generated authorization headers. Use include_preview to return small PNG/JPEG/WebP images directly to the AI; larger files need a local file viewer. Run after auth_fetch finishes.
| Name | Required | Description | Default |
|---|---|---|---|
| urls | Yes | One or more URLs to download | |
| output_dir | No | Optional directory to save files to. Defaults to ~/.auth-fetch-mcp/downloads/<timestamp>/ | |
| include_preview | No | Include small PNG/JPEG/WebP images as MCP image content, within a shared 1 MiB preview budget. Local paths are always returned. |
| Name | Required | Description |
|---|---|---|
| files | Yes | |
| total | Yes | |
| status | Yes | |
| directory | Yes | |
| downloaded | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true) cover the mutation/open-world profile, and the description adds genuinely new context: cookie limitations against JavaScript-generated authorization headers, per-file error reporting, and the 1 MiB preview budget behavior. Does not contradict the write-hint by hiding that files land on disk.
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-loaded with the core action, then limitation, then verification requirement, then the preview branch. Every sentence carries actionable information with no filler.
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?
An output schema exists, so return shapes need not be restated, yet the description still notes the returned fields and error surface. Combined with the auth caveat and sequencing relative to auth_fetch, an agent has everything needed to invoke it correctly.
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 baseline is 3, but the description adds real meaning to include_preview (returns small PNG/JPEG/WebP to the AI within a budget; larger files require an external viewer) beyond what the schema states. output_dir and urls remain schema-only.
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 (download) and resource (attachments/media) plus the mechanism (saved browser cookies) and scope constraint (only what the task needs). It is clearly distinguishable from siblings like auth_fetch and list_pages.
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 explicit sequencing ('Run after auth_fetch finishes'), a success-verification instruction ('Check downloaded before reporting success'), and a conditional routing rule for include_preview (small images inline vs. larger files needing a local viewer). Covers both when to use and how to branch.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Inspect open browser tabs without navigating. Returns URLs and titles; it does not capture page content.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
| Name | Required | Description |
|---|---|---|
| count | Yes | |
| pages | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: it does not navigate (no side effects on the pages) and 'does not capture page content', explicitly bounding what the tool will and will not return. That boundary is the kind of detail annotations cannot express.
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?
Two short sentences, zero filler, with the scope constraint ('without navigating') placed first and the output/limitation statement second. Every clause earns its place.
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 zero-parameter, read-only, idempotent list tool with an output schema present, the description covers everything needed to call it correctly: what it enumerates, that it has no navigation side effect, and what data it returns versus omits. Return-value detail is legitimately delegated to the output schema.
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 tool takes zero parameters, which is the baseline-4 case per the rubric. There is nothing for the description to clarify, and it correctly describes the output shape (URLs and titles) instead of inventing parameters.
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 (Inspect) and resource (open browser tabs), and the qualifier 'without navigating' narrows the scope precisely. It does not name or differentiate against siblings like close_browser or auth_fetch, but the resource is unambiguous enough that confusion is unlikely.
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?
Usage is implied by the phrase 'open browser tabs' rather than stated: an agent can infer this is the tool for enumerating existing tabs. There is no explicit when-to-use condition, no exclusions, and no reference to the sibling tools that also touch browser state.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
v4.0.0auth_fetch5 fields changedInput schema / properties / formatAdded value: +{
+ "default": "text",
+ "description": "Defaults to readable text. Select html when markup is needed.",
+ "enum": [
+ "html",
+ "text"
+ ],
+ "type": "string"
+}Input schema / properties / max_charsAdded value: +{
+ "default": 20000,
+ "description": "Maximum returned content characters. Defaults to 20000; check truncated.",
+ "maximum": 100000,
+ "minimum": 1000,
+ "type": "integer"
+}Input schema / properties / timeout_secondsAdded value: +{
+ "default": 600,
+ "description": "Time allowed for manual login and Capture page. Configure the client's tool timeout to be longer.",
+ "maximum": 1800,
+ "minimum": 30,
+ "type": "integer"
+}Input schema / properties / wait_for / descriptionPrevious value: -"Optional CSS selector to wait for before capturing (useful for SPAs)"New value: +"CSS selector that must be visible after the user captures. A missing selector returns an error."Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": false,
+ "properties": {
+ "captured_at": {
+ "type": "string"
+ },
+ "content": {
+ "type": "string"
+ },
+ "format": {
+ "enum": [
+ "html",
+ "text"
+ ],
+ "type": "string"
+ },
+ "links": {
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "label": {
+ "type": "string"
+ },
+ "url": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "url",
+ "label"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "links_truncated": {
+ "type": "boolean"
+ },
+ "media": {
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "downloadable": {
+ "type": "boolean"
+ },
+ "label": {
+ "$ref": "#/properties/links/items/properties/label"
+ },
+ "type": {
+ "type": "string"
+ },
+ "url": {
+ "$ref": "#/properties/links/items/properties/url"
+ }
+ },
+ "required": [
+ "url",
+ "label",
+ "type",
+ "downloadable"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "media_truncated": {
+ "type": "boolean"
+ },
+ "original_length": {
+ "type": "number"
+ },
+ "status": {
+ "const": "ok",
+ "type": "string"
+ },
+ "title": {
+ "type": "string"
+ },
+ "truncated": {
+ "type": "boolean"
+ },
+ "url": {
+ "type": "string"
+ },
+ "warnings": {
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "status",
+ "url",
+ "title",
+ "content",
+ "format",
+ "captured_at",
+ "truncated",
+ "original_length",
+ "links",
+ "media",
+ "links_truncated",
+ "media_truncated",
+ "warnings"
+ ],
+ "type": "object"
+}close_browser1 field changedOutput schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": false,
+ "properties": {
+ "message": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "message"
+ ],
+ "type": "object"
+}download_media4 fields changedInput schema / properties / include_previewAdded value: +{
+ "default": false,
+ "description": "Include small PNG/JPEG/WebP images as MCP image content, within a shared 1 MiB preview budget. Local paths are always returned.",
+ "type": "boolean"
+}Input schema / properties / urls / maxItemsAdded value: +50Input schema / properties / urls / minItemsAdded value: +1Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": false,
+ "properties": {
+ "directory": {
+ "type": "string"
+ },
+ "downloaded": {
+ "type": "number"
+ },
+ "files": {
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "error": {
+ "type": "string"
+ },
+ "localPath": {
+ "type": "string"
+ },
+ "preview_included": {
+ "type": "boolean"
+ },
+ "size": {
+ "type": "number"
+ },
+ "url": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "url"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ },
+ "status": {
+ "enum": [
+ "ok",
+ "partial",
+ "error"
+ ],
+ "type": "string"
+ },
+ "total": {
+ "type": "number"
+ }
+ },
+ "required": [
+ "status",
+ "directory",
+ "downloaded",
+ "total",
+ "files"
+ ],
+ "type": "object"
+}list_pages1 field changedOutput schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": false,
+ "properties": {
+ "count": {
+ "type": "number"
+ },
+ "pages": {
+ "items": {
+ "additionalProperties": false,
+ "properties": {
+ "title": {
+ "type": "string"
+ },
+ "url": {
+ "type": "string"
+ }
+ },
+ "required": [
+ "url",
+ "title"
+ ],
+ "type": "object"
+ },
+ "type": "array"
+ }
+ },
+ "required": [
+ "pages",
+ "count"
+ ],
+ "type": "object"
+}download_mediav2.0.7auth_fetchclose_browserlist_pagesScored across 4 tools
Each tool targets a distinct browser action: list_pages inspects tabs, auth_fetch captures content, download_media fetches attachments, and close_browser tears down. Boundaries are clean and the descriptions reinforce the sequencing (auth_fetch before download_media, close only when cancelling).
close_browser, download_media, and list_pages follow a clear verb_noun snake_case pattern. auth_fetch deviates slightly (reads as noun/qualifier + verb) but remains readable and consistent in casing.
Four tools is well-scoped for a narrow authenticated-fetching purpose, with each tool earning its place. No redundant or filler tools, nothing obviously missing at this count.
The full lifecycle is covered: inspect tabs, capture content, download media, and close the browser. A dedicated navigation/URL-open tool appears absent, but list_pages plus the user-driven capture flow largely compensates.
Cloud browsers for AI agents: get past bot detection, sign in with MFA, run web tasks at scale.
Read, crawl and act on websites, signed in as the user, and turn any site into an API.
Stealth web automation for AI agents. Login, signup, navigate, screenshot.
Stealth web automation for AI agents. Login, signup, navigate, screenshot.