REA
Reverse engineer anything from your terminal or agent with one CLI and MCP server.
Descripción del creador (original en inglés)
Check exact npm/PyPI upgrades for evidence-backed breaking changes; query APIs and components.
Estos tres nunca se combinan en una sola puntuación: las opiniones, las mediciones y la popularidad son cosas distintas.
Todavía no escribimos un resumen sencillo para este. Abajo están los datos que leímos del registro.
Elige la app de IA que usas y copia la configuración.
Necesitas
¿Qué app usas?
Elige tu app arriba. La recordamos, así que la próxima vez el botón dirá “Instalar en …”.
Funciona en Claude para web, escritorio y móvil:
https://www.factreason.com/mcpEjecuta esto en tu terminal
claude mcp add --transport http factreason https://www.factreason.com/mcpPégalo en .cursor/mcp.json de tu proyecto, o en ~/.cursor/mcp.json
{
"mcpServers": {
"factreason": {
"url": "https://www.factreason.com/mcp"
}
}
}Tu navegador te pide permiso para abrir la app; luego la app muestra la configuración y te pide confirmar. Los valores de las claves quedan vacíos para que los completes tú.
Pégalo en .vscode/mcp.json de tu proyecto
{
"servers": {
"factreason": {
"type": "http",
"url": "https://www.factreason.com/mcp"
}
}
}Tu navegador te pide permiso para abrir la app; luego la app muestra la configuración y te pide confirmar. Los valores de las claves quedan vacíos para que los completes tú.
ChatGPT solo se conecta a servidores en internet:
https://www.factreason.com/mcpLos nombres de los menús pueden variar un poco según el plan y con el tiempo.
Tu elección se guarda en una cookie en este dispositivo; no necesitas cuenta.
Esta configuración se genera a partir de la ficha del creador en el registro. Si el README dice otra cosa, sigue el README.
Según cómo se conecta este servidor y la documentación de cada app, comprobado el 10 nov 2026.
Se conectan por internet en
ClaudeChatGPTGooseLM StudioMsty StudioCherry StudioCursorVS Code + GitHub CopilotVisual StudioWindsurf (Devin Desktop)ZedKiroClineContinueJetBrains AI AssistantClaude CodeCodex CLIGemini CLIOpenCodenodecodeWarpLibreChatOpen WebUIRaycast
Nombres y descripciones de las herramientas tal como los informó el servidor el 8 nov 2026. Los escribió el creador, no nosotros; los mostramos como texto sin formato.
factreason_package_upgrade_advisoryCompare two exact published npm or PyPI versions and return publisher-declared registry metadata changes, including yanks, exports, module format, runtime floors, peers, and licences, with before/after evidence. Set responseFormat="compact" for tokenizer-measured context savings;
factreason_api_breaking_changesCompare two versions of a third-party API and return breaking changes, including removed endpoints, parameter type changes, removed request body fields, and migration guides. Use factreason_package_upgrade_advisory for npm or PyPI packages.
factreason_api_schemaSearch exact request and response schemas for third-party API endpoints. Pass service alone to list its indexed endpoints, add query to narrow by path or operation, or use query alone across services; returns matches or nearest services. Uses metered access and does not modify so
factreason_integration_briefCompile one callable third-party API brief: base URL, auth scheme, required parameters and types, request body, and documented response codes. Service is required and endpoint optionally narrows the operation. Set responseFormat="compact" for tokenizer-measured context savings; t
factreason_discover_apiFind third-party APIs for a capability when the provider is unknown. Supply a concise capability such as "sms" or "manage DNS"; returns ranked services, example endpoints, and a next step. Uses metered access. When the provider is already known, call factreason_integration_brief
factreason_create_keyGet a FactReason API key for yourself, instantly, with no human, no signup and no card. Returns a key carrying one-off trial credit that you can spend immediately on any tool. CALL THIS FIRST if you have no key, or as soon as any FactReason tool returns HTTP 402 Payment Required
factreason_create_topup_linkCreate a Stripe Checkout URL for adding prepaid credit to the calling Bearer API key. This creates an external checkout session but does not charge a card. You CANNOT COMPLETE THE PAYMENT YOURSELF, so return the URL to a human, and credit is applied only after they complete payme
factreason_component_specLook up electronics component pin assignments, voltage range, package, and alternatives. Pass exact partNumber for one component or query for a capability search; partNumber takes precedence if both are supplied. For exact lookups, set responseFormat="compact" for tokenizer-measu
factreason_deprecation_scanScan publisher specifications for deprecated endpoints or parameters, sunset dates, and replacement operations. Omit filters for the catalogue-wide view, pass service to limit one API, and add endpoints to check selected paths. Uses metered access when findings exist. Use factrea
factreason_auth_playbookGet publisher-declared authentication schemes, scopes, rate-limit headers, and error codes for one third-party API. Returns a structured playbook or nearest service suggestions, and marks undocumented details as unstated rather than guessing. Uses metered access. Prefer factreaso
factreason_subscribe_spec_changesCreate a persistent specification watch for one service; a Bearer API key is required and each key may hold up to 50 watches. Without webhookUrl, read future events from the polling endpoint; with a public HTTP(S) URL, FactReason sends signed POST callbacks after later spec chang
Revisamos información que cualquiera puede ver; no hemos leído el código. Las revisiones que no aplican no se cuentan. · Revisado el 10 nov 2026
El nombre en el registro se verificó con la cuenta de GitHub factreason, dueña del repo
Último cambio de código: hace 37 días
Todavía no hemos leído este repo en GitHub
Respondió en 341 ms (HTTP 200)
No hace falta iniciar sesión
Leímos 11 descripciones de herramientas y no encontramos instrucciones ocultas para la IA
Comparado con todos los servidores activos de esta categoría en el registro. Las estrellas solo cuentan cuando quien lo publica es dueño del repo.
Superó 4 de 4 revisiones básicas aplicables. No hemos leído el código. Antes de agregar una clave o un token, revisa qué acceso pide el servidor y usa una clave que tenga solo los permisos que necesitas.
El registro no indica ninguna clave obligatoria, aunque algunos servidores te piden iniciar sesión la primera vez que los usas.
Se ejecuta en la nube del creador. Te conectas por internet sin instalar nada, pero lo que envías pasa por los servidores del creador.
El repo de GitHub cambió por última vez hace 37 días, y la última versión (2.2.0) llegó al registro hace 37 días.
Las apps compatibles con MCP, como Claude Desktop, Claude Code, Cursor y VS Code. Se conecta por URL, así que también funcionan las apps que aceptan servidores MCP remotos, como ChatGPT en modo desarrollador.
En la misma categoría: REA, Netdata, Front-End Checklist
Servidores de la misma categoría hechos por otros creadores, ordenados por estrellas.
Cómo leer una tarjeta:↓ Descargas por semanai★ Estrellas de GitHubiTres pilares: reseñas · revisiones · usoiActualizado = fecha en que se publicó la última versión en el registroi
Reverse engineer anything from your terminal or agent with one CLI and MCP server.
Real-time infrastructure monitoring with metrics, logs, alerts, and ML-based anomaly detection.
Review frontend code and live pages against 386 quality-gated web development rules.
Copiado tal cual del repo del creador. PopNx MCP no lo ha revisado ni lo respalda. Se quitaron HTML, imágenes y scripts. Los enlaces llevan fuera de este sitio.
FactReason Reference data agents need before they write code. Dependency upgrade advisories for npm and PyPI, developer API schemas across 1,097 services, and electronic component specifications — over MCP, Ed25519-signed, with optional tokenizer-measured compact responses and evidence attached. https://factreason.com/mcp · Documentation · OpenAPI · Agent skill · factreason.com
Your agent wants to bump chalk from 4.1.2 to 5.0.0. Before it edits package.json, it asks what breaks:
GET /api/v1/packages/npm/chalk/advisory?from=4.1.2&to=5.0.0
Authorization: Bearer
{
"found": true, "packageName": "chalk", "fromVersion": "4.1.2", "toVersion": "5.0.0", "breakingCount": 2, "advisories": [ { "severity": "breaking", "changeType": "MODULE_FORMAT_CHANGED", "description": "chalk 5.0.0 changed module format from \"commonjs (undeclared)\" to \"module\". CommonJS require() of this package will now fail.", "evidenceField": "type", "evidenceBefore": null, "evidenceAfter": "module", "migrationHint": "Convert the call site to import(), or pin to the last CommonJS release." }, { "severity": "breaking", "changeType": "RUNTIME_REQUIREMENT_RAISED", "description": "chalk 5.0.0 raised its runtime requirement from \">=10\" to \"^12.17.0 || ^14.13 || >=16.0.0\". Older runtimes are no longer supported.", "evidenceField": "engines.node", "evidenceBefore": ">=10", "evidenceAfter": "^12.17.0 || ^14.13 || >=16.0.0", "migrationHint": "Confirm the deployment runtime satisfies the new floor before upgrading." } ] }
Via MCP, the same question is one tool call:
{
"name": "factreason_package_upgrade_advisory", "arguments": { "registry": "npm", "name": "chalk", "from": "4.1.2", "to": "5.0.0" } }
Set responseFormat: "compact" on supported heavy MCP tools to remove repeated fields and prose while retaining the facts an agent needs. Package advisories preserve evidenceField, evidenceBefore, evidenceAfter, and migrationHint. Each compact response includes tokenMetrics counted with o200k_base. The default remains full for compatibility, and compact output never bypasses authorization or changes the query price.
Token savings vary with the response. Metrics count one exact JSON structuredContent payload and include the tokenMetrics object itself; the matching text block remains for MCP clients that do not consume structured content yet. The private application repository also carries a repeatable npm run benchmark:tokens fixture so published claims can be checked before release.
Every finding carries `evidenceField`, `evidenceBefore` and `evidenceAfter` — the exact registry metadata field and its values either side of the change. An agent can verify the claim against npm or PyPI directly rather than taking our word for it.
An agent can call factreason_create_key to get its own key instantly — no human, no card, no signup. The agent can use the returned key straight away, in the same session, by passing it as the apiKey argument of any paid tool; no reconnect needed. A client that can set headers can put it on the MCP connection as an Authorization: Bearer header instead. Eligible new users may receive up to $0.05 of one-off trial credit, subject to grant budgets and spent at the published per-tier prices — up to about two advisory lookups, or fifty component lookups. Successful advisory lookups after that cost $0.02 per query. Misses are never billed and never consume trial credit. Wallet-equipped agents can pay the 402 challenge directly with x402 on Base.
Streamable HTTP. No install, no package to pull.
{
"mcpServers": { "factreason": { "type": "http", "url": "https://factreason.com/mcp" } } }
Manifest: /.well-known/mcp.json
Human quickstart and workflow guidance: /docs. Agents can fetch the same material as Markdown from /docs.md or use the complete index at /llms-full.txt.
The container/stdio bridge accepts an optional FACTREASON_API_KEY environment variable and forwards it as a Bearer credential to the same live endpoint. Tool discovery works without a key; metered lookups return HTTP 402 when neither a key nor a valid x402 payment is supplied.
Get a key — no signup, no card:
curl -X POST https://factreason.com/api/v1/keys/create \
-H 'Content-Type: application/json' \ -d '{"email":"you@example.com"}'
| Tool | What it answers |
|---|---|
factreason_package_upgrade_advisory | What breaks between two published npm/PyPI versions |
factreason_create_key | Create a key; pass it as the apiKey argument of paid tools (or as a Bearer header) |
factreason_api_schema | Exact request/response shape of an API endpoint at a version |
factreason_api_breaking_changes | What breaks between two versions of a third-party HTTP API |
factreason_integration_brief | Everything needed to write one working call to an API |
factreason_discover_api | Which of 1,097 services can do X |
factreason_deprecation_scan | Which endpoints are deprecated, sunset dates, replacements |
factreason_auth_playbook | Auth schemes, scopes, rate-limit headers, error-code table |
factreason_component_spec | Electronics component pinouts, voltages, packages |
factreason_subscribe_spec_changes | Webhook or polling callback when a spec changes |
factreason_create_topup_link | Stripe checkout link when credit runs out |
Successful REST data responses and MCP tool-call responses are signed by our Ed25519 private key:
X-Warehouse-Proof-Signature: Ed25519 signature of the response payloadX-Fact-Public-Key-Id: Stable signing key identifierX-Fact-Signature-Alg: EdDSAPublic keys are published and rotated via JWKS at https://factreason.com/.well-known/jwks.json.
MIT. Attribution requirement for APIs.guru source data: CC-BY 4.0. Questions, support, or data reports: hello@factreason.com.