Elfa MCP README
The full upstream README, mirrored here for reference. Install config, tool schemas, adoption signals, and an original overview live on the Elfa MCP listing page.
Elfa MCP
Model Context Protocol server for the Elfa API — crypto social intelligence from X and Telegram, plus Auto, a condition engine that watches the market and fires an action when your conditions are met.
Works with any MCP client: Claude Code, Claude Desktop, Cursor, VS Code, Codex, and anything else that speaks MCP.
Install
Get an API key at dev.elfa.ai. No install step — npx fetches the server on demand.
One click
Claude Desktop
Download elfa-mcp-<version>.mcpb from the latest release and open it. Claude Desktop installs it, prompts for your API key, and keeps it updated. Nothing else to configure.
Claude Code
Cursor, VS Code, Claude Desktop, and other clients
VS Code uses "servers" instead of "mcpServers". Everything else is the same.
Ask "what's trending in crypto right now?" to confirm it works.
Configuration
| Variable | Required | Purpose |
|---|---|---|
ELFA_API_KEY | yes | Authenticates every request |
ELFA_TIMEOUT | no | Request timeout in ms, default 120000 |
ELFA_RETRIES | no | Retries on failure, default 0 |
ELFA_MCP_MAX_RESPONSE_CHARS | no | Response size ceiling, default 60000 |
ELFA_EXTRA_HEADERS | no | JSON object of extra headers to send upstream, for proxies and non-production environments |
The timeout is high and retries are off on purpose. The interpretation endpoints are LLM-backed and can take over a minute, and they cost credits per attempt, so a silent retry would bill you again for a call you never saw. Raise ELFA_RETRIES only if you are calling the cheap measurement endpoints.
Some MCP clients apply their own timeout, often around 60 seconds. narratives and market_chat can exceed that; the request still completes and is still charged, even if the client gives up first.
Tools
11 tools, mapped to every documented /v2 operation.
| Tool | Mode | Cost | What it does |
|---|---|---|---|
api_status | read | Free | Check API key tier, credit usage and remaining requests. Also confirms the API is reachable. |
mentions | read | 1 per call | Social mentions from X and Telegram. mode=top ranks a ticker's mentions by engagement, mode=search filters by keyword or account, mode=news returns the token news feed, which is X posts from accounts tagged as news sources rather than articles from news outlets. |
trending | read | 1 per call | What is gaining social attention. scope=tokens for tickers, scope=contracts_twitter or scope=contracts_telegram for contract addresses. |
narratives | read | 5 per call | Written narrative analysis with source links. scope=market extracts market-wide narratives, scope=keywords summarises events for specific keywords. |
account_stats | read | 1 per call | Smart follower and engagement stats for an X account. Legacy: it still works, but will be removed on 28 October 2026. |
market_chat | read | Varies by speed | Ask for written market analysis. Supports conversational chat, macro overview, quick summary, token intro, token analysis and account analysis. |
auto_build | read | 1 plus LLM usage | Turn a plain-language monitoring request into an EQL query. Returns a draft to validate and activate, it does not activate anything itself. |
auto_validate | read | Free | Check EQL syntax and get a cost estimate before activating, or check that a symbol has market data on a venue. |
auto_query | read | Free | Read side of Auto: list queries, poll one query, and read its executions and LLM sessions. |
auto_query_write | write | 5 plus LLM usage to create, free to cancel or delete | Activate, cancel or delete an Auto query. Activated queries run unattended and fire their action when conditions are met. |
auto_draft | write | Free, except convert which costs the same as creating a query | Manage inactive Auto drafts. Drafts do not evaluate until converted into an active query. |
Not exposed as tools:
chat-stream-v2— A tool call returns one result, so streaming adds nothing. market_chat covers the same analysis.auto-stream-queries-v2— Long lived streams have no tool equivalent. Poll with auto_query.auto-stream-query-v2— Long lived streams have no tool equivalent. Poll with auto_query.
Some tools depend on the plan: today market_chat, which needs a higher-tier plan than the free one. At startup (stdio) or per request (HTTP, cached for a minute per key), the server reads the key's scopes from /v2/key-status. A tool the plan doesn't include stays listed, but its description says it needs a higher-tier plan, and calling it returns the upgrade link without calling the API or spending credits. If the scopes can't be read within 3 seconds, every tool is listed as usual and the API decides.
Streaming endpoints stay available through the SDKs for applications that can consume SSE.
Where this differs from the raw API
The tools deliberately do not inherit every API default, because an agent pays for verbosity in context.
| API | Here | Why | |
|---|---|---|---|
pageSize | 10 to 50 depending on endpoint, max 100 | 10 | Page through rather than pull everything |
speed on chat | expert | fast | Cheaper by default, ask for expert when depth matters |
| Mention fields | full record | high signal fields | Pass verbosity: "detailed" for the rest |
| Large responses | returned whole | trimmed to fit, with a note | Keeps one call from filling the context window |
Every value is still settable per call, and pageSize accepts up to 100.
Auto
Auto queries run unattended. Once armed, a query keeps evaluating and fires its action without asking again.
The flow is three steps:
auto_build— describe what to watch in plain language, get EQL backauto_validate— check the syntax and get the credit costauto_query_write— activate it
Actions can notify you, call a webhook, message a Telegram bot, or run an LLM analysis.
There is no push channel over MCP. Poll auto_query with method=get, and wait for the returned pollAfterSeconds between calls.
Remote server
The same server runs over Streamable HTTP for hosted deployments:
It is stateless — no sessions, one server instance per request, safe behind a load balancer. Credentials come from the x-elfa-api-key request header, falling back to the environment, or from an OAuth sign-in (see below).
DNS rebinding protection is on by default. The server accepts only the loopback names it binds — localhost:PORT and 127.0.0.1:PORT — which covers the local run above and nothing else. Any deployment that answers on a different Host must list the values it serves:
That includes a public domain, a reverse proxy, and a container that maps the port to a different one than the server binds. A Host the list does not cover is rejected with 403.
| Variable | Required | Purpose |
|---|---|---|
ELFA_MCP_TRANSPORT | no | http to serve over Streamable HTTP, default stdio |
ELFA_MCP_HOST | no | Bind address, default 127.0.0.1 |
ELFA_MCP_PORT | no | Bind port, default 3000 |
ELFA_MCP_ALLOWED_HOSTS | no | Comma separated Host allowlist, defaults to the loopback names bound |
ELFA_MCP_ALLOWED_ORIGINS | no | Comma separated Origin allowlist |
Set ELFA_MCP_ALLOWED_ORIGINS as well when browsers call the server directly. It complements the host allowlist rather than replacing it: a rebound request is same origin, so it carries no Origin header for that list to check, and the Host header is the only one still naming the attacker's domain.
OAuth sign-in
A hosted server can let clients sign in through a browser instead of sending an API key. Set ELFA_MCP_AUTH=oauth and the server becomes an OAuth resource server under the MCP authorization spec:
- A request with no credential gets
401and aWWW-Authenticatechallenge. - The challenge points the client to the protected-resource metadata at
/.well-known/oauth-protected-resource/mcp. - That metadata names the authorization server, where the user signs in.
- The client then sends
Authorization: Bearer <token>. - The server checks the token against the authorization server's introspection endpoint. The endpoint answers with the Elfa API key the request runs as, so the token never reaches the Elfa API.
| Variable | Required in OAuth mode | Purpose |
|---|---|---|
ELFA_MCP_AUTH | yes | oauth to enable, default apikey |
ELFA_MCP_RESOURCE_URL | yes | Canonical URL of this endpoint. Tokens must be issued for exactly this value |
ELFA_OAUTH_ISSUER | yes | Authorization server listed in the metadata |
ELFA_OAUTH_INTROSPECTION_URL | yes | Where tokens are checked |
ELFA_OAUTH_INTROSPECTION_TOKEN | yes | Bearer sent to the introspection endpoint |
ELFA_OAUTH_SCOPES | no | Comma separated scopes to advertise, default elfa |
Notes:
- An
x-elfa-api-keyheader still works in OAuth mode. ELFA_API_KEYis ignored in OAuth mode, so a caller with no credential never runs as the server's own key.- Valid tokens are cached for up to a minute, which bounds how long a revoked token keeps working.
Safety
api_status is the fastest way to tell an auth problem from a credit problem.
Mentions, news and narratives return third-party social text that anyone can write. The server marks it as untrusted in every response, and the server instructions tell the model to treat it as data. Keep that in mind before letting an agent chain from that content into auto_query_write.
Development
npm run verify runs typecheck, tests, the spec drift check, and the docs check.
manifest.json maps every documented API operation to the tool that covers it. npm run check:drift fails if the API grows an operation the server does not handle. The tool table above is generated from the same file with npm run docs:tools.
Links
License
MIT