unitysvc-mcp-server 0.1.3

UnitySVC MCP server starter

UnitySVC MCP Server

Exposes the UnitySVC catalog and account operations to MCP clients — Claude Code, Claude Desktop, Codex, claude.ai — so an agent can discover services, explain how to call them, and (when you supply credentials) operate your account.

It is deliberately thin: it adapts MCP calls to the UnitySVC APIs through the official unitysvc-py and unitysvc-sellers SDKs. Business rules, visibility, billing, and authorization stay in the UnitySVC backend.

Status. Prototype. The table below marks what runs today versus what is designed but not yet built. See unitysvc/unitysvc#1492 for the full design.

	Status
Market + seller listing tools via the official SDKs	✅ implemented
Anonymous marketplace browsing (no credentials)	✅ implemented
stdio transport (default) and HTTP (opt-in)	✅ implemented
Credentials from UNITYSVC_SELLER_API_KEY	✅ implemented
Tools split by mode, advertised on credentials present	✅ implemented
Published to PyPI	✅ v0.1.0
mcp.unitysvc.com deployed	⏳ not yet deployed
how_to_call code-generation tool	⏳ planned

The earlier role-inference bug — where a valid seller key resolved to a customer principal and seller tools rejected it — is fixed by removing role inference entirely.

Two modes

The same package runs in two shapes. They differ only in transport and where credentials come from — the tools themselves are identical.

	Local (stdio)	Hosted (HTTP)
Runs as	a subprocess of your MCP client, on your machine	a service at mcp.unitysvc.com
Credentials	your own API keys, from the process environment	none — by design
Offers	everything: the market view, plus your customer and seller operations	market discovery and how-to guidance only
Reaches	Claude Code, Claude Desktop, Codex	any client, including claude.ai in a browser
Needs	a local Python runtime	nothing

Why the hosted instance holds no credentials. The valuable question — "which service should I use, and how do I call it?" — does not require your key. The catalog is public, and the actual invocation goes from your machine to the gateway with your key, never through us. So the hosted server answers questions and returns copy-pasteable commands; it never acts on your behalf, and there is no credential for it to hold, log, or leak.

It is not a different program. It is this same package running with nothing in its environment, so only the tools that need no credentials are advertised.

Credentials: where they live, and what is never sent

This is the part worth reading carefully.

Local (stdio)

   your MCP client config
        │  populates the child process environment at spawn
        ▼
   unitysvc-mcp-server  (subprocess on your machine)
        │  UNITYSVC_SELLER_API_KEY
        ▼  HTTPS, directly
   api.unitysvc.com  /  seller.unitysvc.com

• Your key lives in your MCP client's configuration and in the environment of a process on your own machine. Nowhere else.
• It is sent only to the UnitySVC API, over HTTPS, by the SDK — the same destination the usvc CLI uses. There is no intermediary.
• It is never sent to mcp.unitysvc.com, and never appears in tool arguments, so it does not enter the model's context, the conversation transcript, or your client's logs.

Exporting the variable in your shell is not enough. MCP clients pass only a safelist of variables to a spawned server — HOME, LOGNAME, PATH, SHELL, TERM, USER — so UNITYSVC_SELLER_API_KEY from your shell profile will not reach the process. You must declare it in the MCP configuration. Use variable expansion so the value stays in your shell rather than being written into a file:

"env": { "UNITYSVC_SELLER_API_KEY": "${UNITYSVC_SELLER_API_KEY}" }

Which key you provide decides what you can do:

You set	You get
nothing	marketplace browsing
UNITYSVC_SELLER_API_KEY	marketplace browsing + your seller listings

There is no customer key. Marketplace browsing does not vary by customer — the backend serves that listing from a fixed active + public filter and ignores caller identity — and the customer-side tools (enrollments, invoke) are not built. UNITYSVC_API_KEY arrives with those, in Phase 3 of unitysvc/unitysvc#1492; until then it is not read.

There is no role to configure. The API key already encodes whether it is a customer or a seller key, and the backend enforces it.

Hosted (HTTP)

No credentials are configured, sent, or held. If you find yourself pasting an API key to use mcp.unitysvc.com, something is wrong — it does not accept one.

Installation

Claude Code — local, with your keys

claude mcp add unitysvc \
  --env UNITYSVC_SELLER_API_KEY="${UNITYSVC_SELLER_API_KEY}" \
  -- uvx --prerelease=allow --from unitysvc-mcp-server unitysvc-mcp-server

Note on --prerelease=allow. This package pins mcp[cli]==2.0.0b1, the MCP Python SDK v2 beta. uv refuses to resolve pre-release dependencies unless told to, so uvx needs that flag. pip install unitysvc-mcp-server needs nothing extra. The flag goes away once MCP SDK v2 ships stable and the pin moves off the beta.

Or project-scoped, in .mcp.json — safe to commit, since the values are expanded from your environment at launch and never written into the file:

{
  "mcpServers": {
    "unitysvc": {
      "type": "stdio",
      "command": "uvx",
      "args": ["--prerelease=allow", "--from", "unitysvc-mcp-server", "unitysvc-mcp-server"],
      "env": { "UNITYSVC_SELLER_API_KEY": "${UNITYSVC_SELLER_API_KEY}" }
    }
  }
}

Omit either variable to run without that role's tools; omit both for anonymous browsing.

Claude Desktop — local, with your keys

~/Library/Application Support/Claude/claude_desktop_config.json (macOS):

{
  "mcpServers": {
    "unitysvc": {
      "type": "stdio",
      "command": "uvx",
      "args": ["--prerelease=allow", "--from", "unitysvc-mcp-server", "unitysvc-mcp-server"],
      "env": { "UNITYSVC_SELLER_API_KEY": "svcpass_..." }
    }
  }
}

Claude Desktop is a GUI application and does not read your shell startup files, so ${VAR} expansion has nothing to expand from — the literal value is required here. That file is not in a repository, but treat it as a secret. Restart Claude Desktop after editing, and note that a JSON syntax error silently disables all configured servers.

Codex — local, with your keys

Codex takes an equivalent stdio entry in ~/.codex/config.toml with command, args, and env. Check the current Codex documentation for the exact key names before relying on it — we have not verified them against a recent release.

claude.ai — hosted, no credentials

Add https://mcp.unitysvc.com/mcp as a custom connector. There is nothing to authenticate and no key to supply. You get catalog discovery and how-to guidance; to act on your account, use one of the local setups above.

Tools

Named for the side of the marketplace they belong to, so it is unambiguous which one answers a given request:

Tools are named for the credential they need, and grouped into one module per requirement — the prefix is the access rule:

Prefix	Requires	Registered	Today
market_	nothing	always	market_list_services(group, limit, cursor)
seller_	UNITYSVC_SELLER_API_KEY	when set	seller_list_services(status, limit, cursor)

So a prefixed tool needs that role's key and market_ is free — a rule an agent can apply without reading descriptions, and one that keeps same-verb pairs unambiguous (customer_get_usage = your spend, seller_get_usage = your revenue).

The hosted deployment runs with an empty environment, so it registers market_ only.

Each description also states explicitly what the tool is not and points at its counterpart, since those descriptions are all a model has when choosing.

Tools are advertised, not just gated. With no seller key, seller_list_services does not appear in tools/list at all, so an agent never sees an option it cannot use and never burns a turn discovering that. The hosted deployment runs with an empty environment, so it advertises exactly the first row.

The previous role-aware list_services has been removed. It existed to paper over an agent not knowing which mode it was in; conditional advertisement answers that directly, and the tool was redundant with the two explicit ones in both modes.

Configuration

Variable	Purpose	Default
UNITYSVC_SELLER_API_KEY	seller API key	unset → seller tools unavailable
UNITYSVC_API_URL	customer API base	https://api.unitysvc.com/v1
UNITYSVC_SELLER_API_URL	seller API base	https://seller.unitysvc.com/v1
UNITYSVC_MCP_TRANSPORT	stdio or http	stdio
UNITYSVC_MCP_HOST / UNITYSVC_MCP_PORT	bind address — HTTP mode only	127.0.0.1 / 8000

The key and URL variables are the SDKs' own, so if you already use the usvc CLI you have them set and need no new values.

Anonymous catalog browsing requires the customer API to serve unauthenticated catalog reads (unitysvc/unitysvc#1610) — merged, but not yet deployed in every environment.

Development

uv sync --dev
uv run pytest
uv run ruff check src/ tests/

Run it:

uv run unitysvc-mcp-server                              # stdio (default)
UNITYSVC_MCP_TRANSPORT=http uv run unitysvc-mcp-server  # HTTP, binds HOST:PORT

The startup log line reports which mode you got — transport, whether any credentials were found, and the tools registered.

The MCP SDK v2 beta is pinned in pyproject.toml; revisit the pin when v2 stabilises.

Design

See unitysvc/unitysvc#1492 for the full design: the two deployment modes, credential handling, MCP specification conformance, and phasing.