Specset
Agents

Use Specset from Codex

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The Specset plugin gives Codex the same construction workflows available in the Claude plugin. It bundles nine skills plus a native MCP connector for project search and structured reads, all powered by the specset CLI.

Install the Codex plugin

Add the public Specset marketplace, then install the plugin:

codex plugin marketplace add specsetai/specset-plugins
codex plugin add specset@specset-plugins

Start a new Codex session after installation so the bundled skills and MCP tools load. You can also run Codex interactively and enter /plugins to inspect installed plugins by marketplace.

If your organization installs plugins through the Codex desktop app, open Plugins, find Specset, and click +. Workspace policy can control which plugins are available.

First run: sign in

Ask Codex a Specset question. The core skill checks the CLI, starts browser sign-in when a browser is visible, and uses device authorization in remote or headless environments:

specset login --device

Approve the displayed code, choose your Specset organization, and start a new Codex session if the MCP tools were not available before sign-in. Credentials remain in the local CLI; Codex receives project data through the authenticated MCP tools.

Try prompts such as:

"Find the product data requirements for the air handling units."

"Compare this submittal PDF with the applicable specification sections."

"Show me the latest RFIs that affect concrete work."

Upload and download files

The local Codex plugin can work with file paths on your computer. When a workflow needs an attachment, Codex uses the streaming upload command and passes the returned cloud file ID to Specset:

specset files upload ./submittal.pdf --json

Downloads use the matching project or record download command. The CLI streams bytes directly, so the agent does not need to hold the complete file in memory.

Verified in Codex

The packaged plugin was tested in a fresh Codex session. Codex discovered all nine Specset skills, loaded the MCP tool catalog, found the CLI upload command, and completed a read-only project-list call without changing remote data.

Keep the plugin current

Refresh the marketplace, reinstall the latest plugin snapshot, and update the CLI:

codex plugin marketplace upgrade specset-plugins
codex plugin add specset@specset-plugins
npm install -g @specset/cli@latest

Start a new session after an update.

Connect ChatGPT through hosted MCP

Codex runs the plugin and CLI locally. ChatGPT connects to Specset's hosted MCP endpoint instead, so it can use the same tool registry without access to local paths.

  1. In ChatGPT, open Settings → Security and login and enable Developer mode if your account and workspace allow it.
  2. Open Plugins, click +, and create a connection to https://app.specbook.ai/mcp.
  3. Complete Specset sign-in and select the organization to bind to the connection.
  4. Start a new chat with the Specset connection enabled.

For hosted file workflows, ChatGPT passes an attached file through a short-lived OpenAI file URL to Specset's uploadFile tool. Downloads return a short-lived resource link through getFileDownload. Local file paths are never exposed to the hosted MCP server.