Claude Code (CLI)

For developers using the CLI.

Confirmed as of v2.1.220 · July 31, 2026

Already using Claude.ai (Web)?

If you already connected Claude.ai (Web), you should be good to go in the CLI — assuming you're logged in there with the same user account. Just type /mcp inside of Claude Code and you should see a line like Valency · ✔ connected · 38 tools.

Prerequisite

You need a Valency account. Sign up here if you haven't already.

1. Open your terminal

2. Add the Valency MCP server:

   claude mcp add --transport http --scope user --callback-port 33418 \
     valency-mcp https://labs.valency.io/mcp/

   Keep --callback-port

   Valency only accepts sign-in redirects on a fixed list of local ports, so the port has to be pinned. Without this flag Claude Code picks a random one on every attempt and sign-in fails with redirect_uri is not registered.

   The flag can only be set when you add the server. If Claude Code reports that port 33418 is already in use, see what to do when the callback port is busy.

3. Start Claude Code:

   claude

4. Authenticate the server. Adding it from the command line does not start the OAuth flow on its own — run the /mcp command inside Claude Code, select the Valency MCP server, and choose to authenticate:

   /mcp

   Complete sign-in when the browser opens, then return to the terminal.

5. Start a new conversation and ask: "Search for papers about quantum computing" (more prompt ideas)

Success: You see paper results in your terminal. You can also explicitly invoke Valency tool calls.

Next steps

Install Valency skills

The Valency plugin layers seven multi-step research workflows on top of the MCP tools — profile, landscape, similar, trends, network, reading-list, and fresh-collaborators. Each one is a prescribed chain of tool calls, not a single search.

From your terminal:

claude plugin marketplace add valency-oss/valency-claude-plugin && claude plugin install valency

Restart Claude Code, then trigger a skill by slash command or natural language:

/valency:profile Yoshua Bengio
What should David Hogg be reading next?

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Need help?

If something isn't working, check Troubleshooting for common fixes. See the FAQ for general questions, or report an issue if you're still stuck.