Skip to content

Codex

This page is written for an agent that needs to install NBER-CLI into Codex without guessing.

What to Install

Use the NBER-CLI Codex plugin.

Repository:

https://github.com/sepinetam/nber-cli

Marketplace name:

nber-cli

Plugin name:

nber-cli

MCP server name:

nber-cli-mcp

The Codex marketplace file is:

.agents/plugins/marketplace.json

The Codex plugin manifest is:

plugins/nber-cli/.codex-plugin/plugin.json

The plugin includes:

  • the NBER-CLI skill
  • the .mcp.json MCP server configuration
  • the uvx nber-cli mcp-server command used to start the MCP server

Install from GitHub

Use this path when Codex can reach GitHub.

Run:

codex plugin marketplace add sepinetam/nber-cli
codex plugin add nber-cli@nber-cli

What each command means:

  • codex plugin marketplace add sepinetam/nber-cli adds this GitHub repository as a Codex marketplace source.
  • codex plugin add nber-cli@nber-cli installs the nber-cli plugin from the nber-cli marketplace.

If the repository was just updated and Codex already knows the marketplace, refresh it:

codex plugin marketplace upgrade
codex plugin add nber-cli@nber-cli

Install from a Local Checkout

Use this path only when the user has already cloned the repository.

Run from anywhere:

codex plugin marketplace add /absolute/path/to/nber-cli
codex plugin add nber-cli@nber-cli

Replace /absolute/path/to/nber-cli with the real path to the repository root. The repository root is the directory that contains .agents/plugins/marketplace.json.

Verify the Plugin

List marketplaces:

codex plugin marketplace list

List plugins:

codex plugin list
codex plugin list --marketplace nber-cli

Expected result:

  • marketplace nber-cli is visible
  • plugin nber-cli is visible
  • plugin nber-cli is installed after codex plugin add nber-cli@nber-cli

If the plugin does not appear, the marketplace source is wrong or stale. Add the repository again or run:

codex plugin marketplace upgrade

Verify the MCP Server

The installed plugin should provide an MCP server named:

nber-cli-mcp

Check configured MCP servers:

codex mcp list
codex mcp list --json

If you need details for the server:

codex mcp get nber-cli-mcp
codex mcp get nber-cli-mcp --json

If the server fails to start, run:

uvx nber-cli --help
uvx nber-cli mcp-server

If uvx nber-cli --help fails, install uv first or fix PATH. If uvx nber-cli mcp-server fails, report the exact error.

Verify NBER-CLI Behavior

Run direct CLI checks:

uvx nber-cli --help
uvx nber-cli info w25000 --format json
uvx nber-cli search "labor economics" --format json

Then ask Codex:

Use NBER-CLI to show the abstract for NBER paper w25000.

Expected behavior:

  • Codex should use the NBER-CLI skill or MCP server.
  • It should not ask the user to clone the repository.
  • It should not assume that nber-cli is already installed.
  • It may use uvx nber-cli ....

If Plugin Installation Fails

Use this fallback only when the plugin path above is unavailable.

Add the MCP server manually:

codex mcp add nber-cli-mcp -- uvx nber-cli mcp-server

Then provide Codex with the skill content from:

plugins/nber-cli/skills/NBER-CLI/SKILL.md

If the user does not have this repository checked out, tell them to read the skill from:

https://github.com/sepinetam/nber-cli/blob/master/plugins/nber-cli/skills/NBER-CLI/SKILL.md

Manual MCP JSON equivalent:

{
  "mcpServers": {
    "nber-cli-mcp": {
      "command": "uvx",
      "args": ["nber-cli", "mcp-server"]
    }
  }
}

Common Mistakes

Use these exact values:

Setting Value
Repository https://github.com/sepinetam/nber-cli
Marketplace nber-cli
Plugin nber-cli
MCP server nber-cli-mcp

Order matters: add the sepinetam/nber-cli marketplace before installing the plugin. If using a local checkout, use the repository root as the marketplace source; it is the directory containing .agents/plugins/marketplace.json. Do not clone the repository just to run the CLI; use uvx nber-cli ....

Access Policy

NBER-CLI does not bypass NBER access controls. If NBER returns 403, 404, an access-denied page, or a download-limit response, report that result to the user. Do not rotate proxies, share credentials, bypass CAPTCHA, or disguise traffic.