Connect a client

The two connection forms

Almost every MCP client accepts one of these.

Remote HTTP — the hosted service. Nothing to install.

url:     https://api.unlob.com/mcp
header:  x-api-key: ulb_…

stdio bridge — for clients that only speak stdio. mcp-remote is a small proxy that speaks stdio to your client and HTTP to us:

npx -y mcp-remote https://api.unlob.com/mcp --header "x-api-key: ${UNLOB_API_KEY}"

Prefer the remote form where the client supports it: it is one fewer process, one fewer thing to keep updated, and it does not need Node installed.

Clients

Client	Native remote HTTP	Page
Claude Code	Yes	Claude Code
Claude Desktop	Via connectors	Claude Desktop
Cursor	Yes	Cursor
VS Code (Copilot)	Yes	VS Code
Codex CLI	Version-dependent	Codex CLI
Cline, Windsurf	Version-dependent	Cline and Windsurf
ChatGPT	Via connectors	ChatGPT
MCP Inspector	Yes	MCP Inspector

Building your own client, or using a framework? Seven framework guides start at LangChain, and n8n covers the no-code path. Or call the REST API directly.

Keep the key out of the file

Every configuration below can hold a literal key, and most of these files end up in a repository or a dotfiles backup. Use an environment variable where the client expands one, and check that the file is git-ignored where it does not.

ulb_ keys are shown once and can be rotated freely, so if one does end up committed, rotate it in the console rather than trying to scrub history.

After connecting

Ask the client to list its tools. You should see eleven:

web_search  get_document  similar  why_not  browse  related
corroborate  authorities  dossier  path  assemble_context

Zero tools and no error message is the characteristic MCP failure, and it is almost always the handshake rather than the tools. Troubleshooting has the one curl command that tells you which step failed.

Telling the agent what it has

Most clients read the server’s instructions, so the agent already knows roughly what unlob is. Two habits are worth adding to your own prompt, because they are what make the difference between using this API and using any search API:

• Prefer assemble_context for “what should I know about X”; prefer web_search for “find the page that says Y”.
• Run corroborate on anything you are about to state as established fact.