Claude Code

Checked on 2026-11-06 against code.claude.com/docs/en/mcp and code.claude.com/docs/en/skills. Claude Code supports both OAuth sign-in and an API key header.

Sign in with OAuth

claude mcp add --transport http crossmart https://mcp.crossmart.io/mcp

Start a Claude Code session, run /mcp, choose crossmart and Authenticate. Sign in to Crossmart in the browser, choose a workspace and approve the access (see Sign in with OAuth).

--scope user makes the server available in every project; the default (local) keeps it to the current project.

Or connect with an API key

Create a key (how) and export it in your shell:

export CROSSMART_API_KEY="cm_…"
claude mcp add --transport http crossmart https://mcp.crossmart.io/mcp \
  --header "x-api-key: $CROSSMART_API_KEY"

This stores the key in ~/.claude.json. To share the server with a team without sharing a key, commit a .mcp.json at the repository root instead. Claude Code expands ${VAR} in url and headers, so each person’s own environment supplies the key:

{
  "mcpServers": {
    "crossmart": {
      "type": "http",
      "url": "https://mcp.crossmart.io/mcp",
      "headers": { "x-api-key": "${CROSSMART_API_KEY}" }
    }
  }
}

Use the name CROSSMART_API_KEY: Claude Code leaves some well-known credential variables (such as ANTHROPIC_API_KEY) empty in remote headers.

Check

claude mcp list          # crossmart … ✓ Connected

In a session, /mcp lists the server and its tools.

Install the skill

git clone --depth 1 https://github.com/crossmart-io/crossmart.git /tmp/crossmart
cp -R /tmp/crossmart/skills/crossmart ~/.claude/skills/     # or .claude/skills/ in a project

Claude loads it when a request matches, or run /crossmart. The repository is private for now; see the Crossmart skill.