SkyAccess

SkyAccess MCP server

SkyAccess is the world's largest empty leg marketplace by listing volume. This free, public MCP server lets any AI assistant search 5,000+ live empty leg flights from 900+ FAA Part 135 (and international equivalent) certified charter operators, often 25 to 75% below a comparable full charter. It also returns indicative charter price estimates and a booking link the traveler can open.

Use the hosted endpoint. Nothing needs to be installed.

https://mcp.skyaccess.com/mcp

Connection details

Endpoint	https://mcp.skyaccess.com/mcp
Authentication	None. The server is free and anonymous: no account, sign-up, API key or OAuth.
Transport	Streamable HTTP, POST only, stateless. No Mcp-Session-Id is issued, so every request stands alone. GET returns 405 by design.
Required headers	Content-Type: application/json. Accept can be the MCP spec value application/json, text/event-stream, application/json alone, */*, or left out. An Accept value that does not list application/json and is not just */* (for example text/html or text/event-stream alone) returns 406.
Response format	With Accept: application/json, text/event-stream, each reply is one Server-Sent Events message: event: message, then data: followed by the JSON-RPC response. With application/json alone, */* or no Accept header, each reply is plain JSON (Content-Type: application/json).
Protocol version	2025-06-18. 2025-11-25, 2025-03-26 and 2024-11-05 are also negotiated.
Rate limits	Tool calls: 30 requests per 60 seconds per client IP. Connection setup is not counted. request_booking: 10 charter enquiries per hour per client IP. See Rate limits.
Coverage	Global inventory, most of it in the United States. Prices and estimates are in USD.
Payments	None. No tool takes a payment or has a payment field.
Support	contact@skyaccess.com
Privacy policy	https://skyaccess.com/privacy#connector
Terms of service	https://skyaccess.com/terms

Connect from an MCP client

Any client that supports remote MCP servers over Streamable HTTP can use the endpoint directly. Leave authentication empty.

• Claude (claude.ai and Claude Desktop): Settings, Connectors, Add custom connector, then paste https://mcp.skyaccess.com/mcp.

• Claude Code:

  claude mcp add --transport http skyaccess https://mcp.skyaccess.com/mcp
  

• Cursor: add this to ~/.cursor/mcp.json:

  { "mcpServers": { "skyaccess": { "url": "https://mcp.skyaccess.com/mcp" } } }
  

• Clients that only speak stdio (for example Claude Desktop's claude_desktop_config.json file): use the bridge in this repository. See Local installer and stdio bridge.

Try it with curl

List the tools:

curl -sS https://mcp.skyaccess.com/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

Search empty legs (read-only):

curl -sS https://mcp.skyaccess.com/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"search_empty_legs","arguments":{"origin":"Los Angeles","destination":"Las Vegas","passengers":4}}}'

The server is stateless, so both commands work without an initialize handshake. MCP clients still send one, and the server answers it normally.

Tools

Tool	Type	What it does
search_empty_legs	Read-only	Searches live empty leg flights by origin, destination, departureDateFrom, departureDateTo, passengers and max_price (USD), all optional. Returns up to 5 flights with route, departure time, whole-aircraft price (taxes and fees shown at checkout), aircraft, seats, amenities, flightId and a booking link.
get_flight	Read-only	Re-reads one flight by flightId, or says it is no longer available.
booking_handoff	Read-only	Returns the SkyAccess booking page link for a flightId. It creates, holds or changes nothing; the traveler reviews and books on the page.
get_charter_estimate	Read-only	Returns an indicative USD price range per aircraft category, with flight time, for a charter from origin to destination (optional passengers and aircraftCategory).
request_booking	Write	Sends the traveler's name, email and trip details (origin, destination, departureDate, passengers, optional notes) to SkyAccess. A SkyAccess specialist follows up by email shortly to confirm availability and price. It takes no payment and creates no booking.

A flight with price: null has no published price (SkyAccess shows it as "Contact for price"). Such flights can appear even when max_price is set, because their price is unknown.

Every tool carries MCP annotations: the four read-only tools set readOnlyHint: true, and request_booking sets readOnlyHint: false.

Example prompts

1. "Find me a private jet from Los Angeles to Las Vegas this week for 4 people." (search_empty_legs)
2. "Are there any cheap private jet flights from Miami to the Bahamas?" (search_empty_legs)
3. "Show me empty legs from Teterboro to Palm Beach and give me the booking link for the cheapest one." (search_empty_legs, then booking_handoff)
4. "How much would it cost to charter a private jet from Teterboro to Aspen for 6 people?" (get_charter_estimate)
5. "What private jet deals are leaving Dallas this weekend?" (search_empty_legs)
6. "Roughly what does a private jet from New York to London cost for 8 passengers?" (get_charter_estimate)

Inventory changes all the time, so the flights returned differ from run to run.

Data and privacy

The four read-only tools need no personal data. request_booking is the only tool that sends personal data: the name and email the traveler gives, plus the trip details and any notes, go to SkyAccess so a specialist can reply. Call it only when the traveler asks SkyAccess to contact them.

How SkyAccess handles this data: https://skyaccess.com/privacy#connector

Rate limits

Current limits, per client IP:

• Tool calls: 30 requests per 60 seconds. Each request that carries a tools/call counts once. Connection setup is not counted: initialize, notifications/initialized, notifications/cancelled, tools/list, ping, and the GET an MCP client sends to open the optional SSE stream (answered 405). A typical client turn (connect, list tools, call one tool) therefore spends 1 request. Any other method counts, and so does a setup request that is over 8 KB, chunked or compressed, or a batch that repeats a setup method. Counted tool-call responses carry RateLimit-Policy: 30;w=60, RateLimit-Limit, RateLimit-Remaining and RateLimit-Reset headers (a request_booking response carries the hourly limit's values instead); setup responses carry none.
• 10 charter enquiries per hour. Only requests that call request_booking count toward this limit.
• Per request: a JSON-RPC batch may carry at most 4 tool calls, and at most 1 request_booking call. Larger batches return 400.

Over a limit, the server answers HTTP 429 with JSON-RPC error code -32029. The RateLimit-Reset header gives the seconds until the window resets; retry after that.

Troubleshooting

Symptom	Cause and fix
406 Not Acceptable	The Accept header does not list application/json and is not just */* (for example text/html or text/event-stream alone). Send Accept: application/json, text/event-stream, application/json or */*, or leave Accept out.
429, JSON-RPC error -32029	A rate limit was reached. "Max 30 requests per minute" is the tool-call limit (connection setup does not count toward it); "Max 10 booking submissions per hour" is the request_booking limit. Wait RateLimit-Reset seconds, then retry.
405	The request was a GET. Send JSON-RPC over POST. MCP clients send one GET to open an optional SSE stream and read the 405 as "no stream offered"; that is expected and does not count toward the rate limit.
400 "Only one request_booking call is allowed per request" or "At most 4 tool calls are allowed per request"	Split the JSON-RPC batch into smaller requests.
"No published empty leg flight matches that id."	The flight is no longer published (booked, withdrawn or departed), or the id is wrong. Run search_empty_legs again.
get_charter_estimate answers "Estimate temporarily unavailable. Please try again."	The same message is returned when a place name is not recognised. Retry with a major city name or an airport code such as KTEB.

Local installer and stdio bridge (npm package coming soon)

The skyaccess-mcp npm package is not published yet, so npx skyaccess-mcp does not work today. Use the hosted endpoint above. Once published, the package will:

1. Write the SkyAccess entry into the config of supported MCP clients found on the machine (Cursor and the Claude Desktop config file), so nobody has to hand-edit JSON.
2. Provide a stdio to HTTP bridge for clients that cannot take a URL.

Run it from a clone today

The connectivity check and the bridge already work from a clone of this repository. They need Node 20 or later and no dependencies:

git clone https://github.com/sky-access/skyaccess-mcp.git
cd skyaccess-mcp
node bin/skyaccess-mcp.mjs doctor

doctor checks the endpoint and lists its tools. It exits non-zero if the endpoint is unreachable or returns no tools.

To use the bridge with a stdio-only client such as Claude Desktop's claude_desktop_config.json, point it at the absolute path of your clone:

{
  "mcpServers": {
    "skyaccess": {
      "command": "node",
      "args": ["/absolute/path/to/skyaccess-mcp/bin/skyaccess-mcp.mjs", "bridge"]
    }
  }
}

Do not run the installer itself (node bin/skyaccess-mcp.mjs with no command) from a clone yet. The Claude Desktop entry it writes starts the bridge through npx -y skyaccess-mcp, which fails until the package is published.

Commands once the package is published

These are not available yet:

npx skyaccess-mcp              # register with every supported client found on this machine
npx skyaccess-mcp --dry-run    # show what would be written, write nothing
npx skyaccess-mcp doctor       # check the endpoint and list its tools
npx skyaccess-mcp bridge       # the stdio to HTTP bridge (clients spawn this)

Options: --url <url>, --client <cursor|claude-desktop>, --dry-run, --help.

How the installer treats your config files

• It only writes to a client whose own directory already exists, so it never creates ~/.cursor on a machine without Cursor.
• It keeps every other key in the file, so your other MCP servers stay as they are.
• It leaves a config that does not parse as JSON untouched and reports it; it never overwrites one.
• It backs up an existing SkyAccess entry to <config>.skyaccess-backup before replacing it.

Design notes

• No runtime dependencies, so there is no transitive supply chain to audit. Plain ESM with no build step: what ships is what is in src/.
• The bridge writes only JSON-RPC to stdout, one message per line, and sends every diagnostic to stderr. A stray stdout write would corrupt the protocol.
• A notification answered with 202 produces no stdout line, because a reply the client never asked for is a protocol violation.
• A failed HTTP hop for a request becomes a JSON-RPC error with the same id, so the client fails fast instead of waiting forever.

Development

npm install          # installs vitest, the only dev dependency
npm test             # offline suite against a real local HTTP server, no network
npm run test:live    # opt-in live suite against https://mcp.skyaccess.com/mcp

The live suite only sends initialize and tools/list. It is kept out of npm test because it depends on DNS and the public internet, neither of which says anything about whether the code is correct.

License

MIT. See LICENSE.