MCP catalog

Nika ships an embedded MCP server catalog aligned with the official MCP Registry schema (v2025-12-11). Each entry declares one or more local-install packages (npm / pypi / oci / cargo / mcpb) and/or remotes (streamable-http / sse endpoints). The workflow YAML invoke: verb references servers by id: Nika handles the rest. Count the live set from the engine source — do not freeze a number here.

Canonical source: crates/nika-catalog/data/mcp-servers.toml. Schema: nika/mcp-servers@1.0. Build-time invariants (enforced in build.rs): unique ids, packages+remotes non-empty, known category, pricing ∈ , alias non-collision.

Overview

Servers

Engine catalog · count the source

Invocation

invoke.tool: mcp:<server>/<tool>

Invoke a configured local server

A catalog entry is a discovery record, not an installed server. Save these files in one project. This example uses a local filesystem server, needs no MCP API key, and gives it access only to ./data.

.nika/mcp_servers.json

{
  "mcp_servers_format": 1,
  "servers": {
    "filesystem": {
      "command": "node",
      "args": ["./node_modules/@modelcontextprotocol/server-filesystem/dist/index.js", "./data"],
      "network": "deny"
    }
  }
}

workflow.nika

nika: read-and-summarise
model: mock/echo
permits:
  tools: ["mcp:filesystem/read_file"]
tasks:
  read:
    invoke:
      tool: "mcp:filesystem/read_file"
      args:
        path: ./data/article.txt
  summarise:
    with:
      page: ${{ tasks.read.output }}
    infer:
      prompt: "Summarise: ${{ with.page }}"
      max_tokens: 1200
outputs:
  summary: ${{ tasks.summarise.output }}

Install the server package in this project, create data/article.txt, then check the workflow. The checker validates the declared server; a successful check does not attest a server installation or handshake. Inspect the installed server before running it. Nika records its tool definitions at the first handshake; subsequent drift requires review. mock/echo keeps model calls offline and echoes the prompt; choose a configured language model for an actual summary.

npm install @modelcontextprotocol/server-filesystem
mkdir -p data
printf 'A short article to read.\n' > data/article.txt
nika check workflow.nika
nika run workflow.nika

The MCP child environment is scrubbed. A catalog’s credential names do not automatically reach a server process, and arbitrary env entries in this registry are not a supported credential transport. Configure a server’s supported authentication before selecting a remote service.

By category

Shipped by the Model Context Protocol project itself.

Id	Title	Registry	Identifier
`filesystem`	Filesystem	npm	`@modelcontextprotocol/server-filesystem`
`memory`	Memory	npm	`@modelcontextprotocol/server-memory`
`pdf`	PDF	npm	`@modelcontextprotocol/server-pdf`

One-liners:

filesystem: read and write local files with path-based access control.
memory: persistent key/value memory store.
pdf: PDF text + structure extraction.

Build systems, browser automation, error trackers, CI / CD.

Id	Title	Registry	Identifier
`aws`	AWS	npm	`aws-mcp`
`bitbucket`	Bitbucket	npm	`@nexus2520/bitbucket-mcp-server`
`browserbase`	Browserbase	npm	`@browserbasehq/mcp`
`browserstack`	BrowserStack	npm	`@browserstack/mcp-server`
`chrome-devtools`	Chrome DevTools	npm	`chrome-devtools-mcp`
`circleci`	CircleCI	npm	`@circleci/mcp-server-circleci`
`cloudflare`	Cloudflare	npm	`@cloudflare/mcp-server-cloudflare`
`eslint`	ESLint	npm	`@eslint/mcp`
`figma`	Figma	npm	`figma-developer-mcp`
`launchdarkly`	LaunchDarkly	npm	`@launchdarkly/mcp-server`
`linear`	Linear	npm	`mcp-server-linear`
`nx`	Nx	npm	`nx-mcp`
`playwright`	Playwright (browser automation)	npm	`@playwright/mcp`
`postman`	Postman	npm	`@postman/postman-mcp-server`
`sentry`	Sentry	npm	`@sentry/mcp-server`
`vercel`	Vercel	npm	`vercel-mcp`
`xcode`	Xcode (build + simulator)	npm	`xcodebuildmcp`

Calendars, project trackers, note-taking, knowledge bases.

Id	Title	Registry	Identifier
`airtable`	Airtable	npm	`airtable-mcp-server`
`clickup`	ClickUp	npm	`@taazkareem/clickup-mcp-server`
`excel`	Excel	npm	`@negokaz/excel-mcp-server`
`google-calendar`	Google Calendar	npm	`@cocal/google-calendar-mcp`
`google-drive`	Google Drive	npm	`@modelcontextprotocol/server-gdrive`
`jira`	Jira	npm	`jira-mcp`
`monday`	Monday	npm	`@mondaydotcomorg/monday-api-mcp`
`n8n`	n8n	npm	`n8n-mcp`
`notion`	Notion	npm	`@notionhq/notion-mcp-server`
`obsidian`	Obsidian (vault access)	npm	`obsidian-mcp`
`slack`	Slack	npm	`@modelcontextprotocol/server-slack`
`zendesk`	Zendesk	npm	`zendesk-mcp`

Embeddings, agents, sandboxes, documentation lookup.

Id	Title	Registry	Identifier
`21st`	21st.dev Magic	npm	`@21st-dev/magic`
`ahrefs`	Ahrefs	npm	`@ahrefs/mcp`
`context7`	Context7	npm	`@upstash/context7-mcp`
`dataforseo`	DataForSEO	npm	`dataforseo-mcp-server`
`e2b`	E2B	npm	`@e2b/mcp-server`
`langchain`	Langchain	npm	`langchain-mcp`
`sequential-thinking`	Sequential Thinking	npm	`@modelcontextprotocol/server-sequential-thinking`
`supadata`	Supadata	npm	`@supadata/mcp`

Scrapers, search APIs, crawlers.

Id	Title	Registry	Identifier
`apify`	Apify	npm	`@apify/actors-mcp-server`
`exa`	Exa	npm	`exa-mcp-server`
`firecrawl`	Firecrawl (scrape + crawl)	npm	`firecrawl-mcp`
`perplexity`	Perplexity (search + sonar)	npm	`perplexity-mcp`
`searchapi`	Searchapi	npm	`searchapi-mcp`
`serper`	Serper	npm	`mcp-server-serper`
`tavily`	Tavily	npm	`tavily-mcp`

Relational, document, key-value, graph stores.

Id	Title	Registry	Identifier
`mongodb`	MongoDB	npm	`mongodb-mcp-server`
`mysql`	MySQL	npm	`mcp-server-mysql`
`neo4j`	Neo4j	npm	`@johnymontana/neo4j-mcp`
`redis`	Redis	npm	`redis-mcp`
`supabase`	Supabase	npm	`supabase-mcp`
`turso`	Turso	npm	`mcp-server-turso`
`upstash`	Upstash	npm	`@upstash/mcp-server`

Dashboards, metrics, product analytics.

Id	Title	Registry	Identifier
`axiom`	Axiom	npm	`mcp-server-axiom`
`datadog`	Datadog	npm	`@winor30/mcp-server-datadog`
`dynatrace`	Dynatrace	npm	`@dynatrace-oss/dynatrace-mcp-server`
`grafana`	Grafana (Go binary via OCI)	oci	`ghcr.io/grafana/mcp-grafana`
`mixpanel`	Mixpanel	npm	`mixpanel-mcp-server`
`plausible`	Plausible	npm	`plausible-mcp`
`prometheus`	Prometheus	npm	`prometheus-mcp`

Headless content platforms, blogs, marketing ops.

Id	Title	Registry	Identifier
`contentful`	Contentful	npm	`@contentful/mcp-server`
`ghost`	Ghost	npm	`ghost-mcp`
`hubspot`	HubSpot	npm	`@hubspot/mcp-server`
`sanity`	Sanity	npm	`@sanity/mcp-server`
`strapi`	Strapi	npm	`strapi-mcp`
`wordpress`	Wordpress	npm	`wordpress-mcp`

Chat, customer messaging, transactional email, SMS.

Id	Title	Registry	Identifier
`discord`	Discord	npm	`discord-mcp`
`intercom`	Intercom (remote OAuth)	remote	`(HTTP)`
`resend`	Resend	npm	`resend-mcp`
`sendgrid`	SendGrid	npm	`sendgrid-mcp`
`telegram`	Telegram	npm	`telegram-mcp`
`twilio`	Twilio	npm	`twilio-mcp`

Payment processors, marketplaces, market data.

Id	Title	Registry	Identifier
`alpaca`	Alpaca	npm	`alpaca-mcp`
`paypal`	PayPal	npm	`@paypal/mcp`
`polygon`	Polygon	npm	`polygon-mcp`
`salesforce`	Salesforce	npm	`@salesforce/mcp`
`shopify`	Shopify	npm	`shopify-mcp`
`stripe`	Stripe	npm	`@stripe/mcp`

Containers, clusters, IaC, PaaS.

Id	Title	Registry	Identifier
`docker`	Docker (daemon control)	npm	`docker-mcp`
`heroku`	Heroku	npm	`@heroku/mcp-server`
`kubernetes`	Kubernetes (cluster API)	npm	`mcp-server-kubernetes`
`pulumi`	Pulumi	npm	`@pulumi/mcp-server`
`railway`	Railway	npm	`@railway/mcp-server`
`terraform`	Terraform	npm	`terraform-mcp-server`

Id	Title	Registry	Identifier
`linkedin`	LinkedIn	npm	`linkedin-mcp`
`reddit`	Reddit	npm	`reddit-mcp`
`tiktok`	TikTok	npm	`tiktok-mcp`
`twitter`	Twitter	npm	`twitter-mcp`
`youtube`	YouTube	npm	`youtube-mcp`

Weather, recipes, news, music, general knowledge.

Id	Title	Registry	Identifier
`news-api`	NewsAPI	npm	`newsapi-mcp`
`openweather`	OpenWeather	npm	`openweather-mcp`
`recipe`	Recipe	npm	`recipe-mcp`
`spotify`	Spotify	npm	`spotify-mcp`
`wolfram`	Wolfram	npm	`wolfram-mcp`

Text-to-image, model inference for images.

Id	Title	Registry	Identifier
`comfyui`	ComfyUI	npm	`comfyui-mcp`
`fal`	Fal	npm	`fal-mcp`
`replicate`	Replicate	npm	`replicate-mcp`

Embeddings stores + ANN search.

Id	Title	Registry	Identifier
`pinecone`	Pinecone	npm	`@pinecone-database/mcp`
`qdrant`	Qdrant (Python via uvx)	pypi	`mcp-server-qdrant`
`turbopuffer`	Turbopuffer	npm	`@turbopuffer/turbopuffer-mcp`

Ad platforms + email marketing.

Id	Title	Registry	Identifier
`google-ads`	Google Ads	npm	`google-ads-mcp`
`mailchimp`	Mailchimp	npm	`mailchimp-mcp`
`meta-ads`	Meta Ads	npm	`meta-ads-mcp`

Geospatial + routing.

Id	Title	Registry	Identifier
`mapbox`	Mapbox	npm	`@mapbox/mcp-server`

Distribution mix

Most catalog entries ship as npm packages (stdio via npx). A few use other registries — pypi (qdrant, via uvx), oci (grafana, a Go binary in a container image), and a pure remote endpoint (intercom, OAuth streamable-http). Count the live mix in mcp-servers.toml; do not freeze it here. The catalog’s registry_type field is validated at build time: runner is required for pypi packages and forbidden for every other registry type.

Authentication

Every server that needs credentials declares at least one [[servers.env_vars]] entry with is_secret = true or false. The env var names are visible in mcp-servers.toml. Search for ^name = under your chosen server.

Nika never stores API tokens in workflow YAML. Secrets are read from environment variables at run time. Use nika doctor to see which provider variables are present or missing; it reports presence only and never prints values.

Verbs

How invoke: routes to MCP tools + built-ins at runtime.

Builtins

The engine-native tools under nika:*.

Providers catalog

LLM providers for the infer: and agent: verbs.

Error codes

MCP errors: the spec’s NIKA-MCP namespace (NIKA-MCP-001 server unreachable · NIKA-MCP-002 call failed); the engine’s internal diagnostics registry stays engine-side.

YAML

Language fields

CLI & errors

Data catalogs

Workspace

Documentation system

Tool contracts

MCP catalog

Overview

Servers

Categories

Invocation

Invoke a configured local server

By category

Distribution mix

Authentication

See also

Verbs

Builtins

Providers catalog

Error codes

​Overview

Servers

Categories

Invocation

​Invoke a configured local server

​By category

​Distribution mix

​Authentication

​See also

Verbs

Builtins

Providers catalog

Error codes

Overview

Invoke a configured local server

By category

Distribution mix

Authentication

See also