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[docs] How to run FastMCP with args or env vars? #339
Description
https://github.com/modelcontextprotocol/python-sdk/tree/main?tab=readme-ov-file#development-mode
# Development Mode
The fastest way to test and debug your server is with the MCP Inspector:
mcp dev server.py
# Add dependencies
mcp dev server.py --with pandas --with numpy
# Mount local code
mcp dev server.py --with-editable .This didn't show how to run with args in dev mode.
Expected to see something like this:
mcp install server.py -v API_KEY=abc123 -v DB_URL=postgres://...
mcp install server.py -f .envHowever this is not dev mode
Reacted by Thanh-Dat (Nikolaj) Nguyen
Activity
thadanguyen commentedon Aug 3, 2025
+1,
--helpalso shows no possible options to add args. I think this is a missing feature. For env vars, you could walk-around by using.envthen load it in the script, but for args, it is not possible yet.felixweinberger commentedon Oct 7, 2025
More support for expanded CLI docs
looney-blooper commentedon Jul 20, 2026
yelo! I'd like to work on this if it's available.
I noticed the v2 MCP development documentation could use a bit more clarity around how
mcp devbehaves. My plan is to updatedocs/run/index.mdto mention that it:--withand--with-editablefor dependencies,I'll keep the scope limited to documentation only. If that sounds good, I'd be happy to take this on. Thanks!