filechanger-mcp

MCP server for FileChanger document conversion. Exposes three tools backed by the FileChanger API:

• convert — convert text content between formats (e.g. markdown to html). Binary outputs (docx/epub/odt) use the REST jobs API instead.
• list_formats — list supported input and output formats.
• docs — return the FileChanger API documentation as markdown.

It is a thin stdio proxy to the hosted endpoint at https://filechanger.io/mcp; the tools themselves run on FileChanger's servers.

Setup

Get an API key (fc_...) at https://filechanger.io, then add to your MCP client config:

{
  "mcpServers": {
    "filechanger": {
      "command": "npx",
      "args": ["-y", "filechanger-mcp"],
      "env": { "FILECHANGER_API_KEY": "fc_your_key_here" }
    }
  }
}

Environment

• FILECHANGER_API_KEY (required) — your FileChanger API key.
• FILECHANGER_URL (optional) — override the endpoint. Defaults to https://filechanger.io/mcp.

Publishing (npm + official MCP registry)

./publish.sh (run via nix develop -c apps/filechanger/mcp/publish.sh) does the whole release: version-sync check across package.json/server.json, build + tests, npm publish (skipped if the version is already up), then mcp-publisher login + publish to registry.modelcontextprotocol.io under the io.filechanger namespace. Directories like PulseMCP and Glama crawl the official registry, so no separate submissions are needed there.

Smithery does not crawl the registry; it lists the hosted endpoint directly (one-time, needs a smithery.ai login):

npx smithery@latest auth login
npx smithery@latest mcp publish "https://filechanger.io/mcp" \
  --config-schema apps/filechanger/mcp/smithery.json

smithery.json tells Smithery's gateway to prompt users for an fc_ key and forward it upstream as the x-api-key header, which /mcp already expects. The scanner needs no auth: initialize and tools/list are open, only tool calls enforce the key.

Namespace ownership is proven over HTTP: nginx serves the Ed25519 public key at https://filechanger.io/.well-known/mcp-registry-auth (infra/configuration.nix) and the script signs the login challenge with the sops-encrypted private key infra/secrets/mcp-registry-key.pem.

One-time prerequisites: npm login, and the well-known nginx location deployed.

Releases are automatic: infra/update-server.sh runs publish.sh --auto after a healthy deploy, which patch-bumps package.json + server.json, commits the bump, publishes, and lays a filechanger-mcp-vX.Y.Z git tag — but only when mcp/ has actually changed since that tag (unchanged deploys skip publishing entirely, and a publish failure only warns, it never fails the deploy). For a manual or non-patch release, bump the version in package.json AND both version fields in server.json yourself, then run the script with no flags.

Reusing the proxy in another project

src/proxy.ts (JSON-RPC parse + HTTP forward) and src/run.ts (stdio loop) are project-agnostic, no FileChanger in them. To stand up a stdio proxy for a different MCP-over-HTTP backend, copy those two files and write your own index.ts: read your key/URL from env and call forward(line, { url, apiKey, fetchFn: fetch, brand: "YourApp" }). brand only flavours error messages (YourApp HTTP 503); it defaults to Upstream. There is no published package yet, so it is copy-the-two-files until a second consumer earns one.