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Prerequisites

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Step 1: Install Codex

If you haven’t already installed Codex, install it first. Once installed, proceed to the next step.

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Step 2: Check for config.toml file

First, check if the config file exists in your Codex directory: 
ls ~/.codex/

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Step 3: Create config file (if needed)

If the file doesn’t exist, create it using this command: 
touch ~/.codex/config.toml

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Step 4: Open config file in editor

Open the config.toml file in your editor: 
code ~/.codex/config.toml -r

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Step 5: Add CORE MCP server configuration

Add the following configuration to your config file: 
[mcp_servers.corememory]
command = "npx"
args = ["-y", "mcp-remote", "https://core.heysol.ai/api/v1/mcp?source=codex", "--header", "Authorization:${AUTH_HEADER}"]
env = { "AUTH_HEADER" = "Bearer {GET API KEY FROM CORE DASHBOARD}" }

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Step 6: Get API key from CORE dashboard

  1. Log into your CORE dashboard at core.heysol.ai
  2. Navigate to Settings (bottom left) Claude Settings
  3. Go to API Key → Generate new key → Name it “codex” Claude Settings
  4. Replace {GET API KEY FROM CORE DASHBOARD} in the config with your actual API key
What this does: This establishes the connection between Codex and CORE’s memory system using OAuth2 Bearer token authentication.

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Step 7: Authenticate the MCP

  1. Start Codex CLI
  2. The MCP server should now be available
  3. Follow any authentication prompts that appear
  4. Grant permissions when prompted to allow Codex access to your CORE memory

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Step 8: Test the connection

Test your setup by asking Codex to summarize your codebase architecture and add it back to memory: 
# Example: Ask Codex to analyze and remember your project
codex "Can you summarize our codebase architecture and store this summary in CORE memory for future reference?"

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Troubleshooting

Connection Issues:
  • Ensure you’re logged into your CORE account in the browser
  • Check that the config.toml file is properly formatted
  • Verify your API key is correct and hasn’t expired
  • Restart Codex CLI if authentication seems stuck
Authentication Issues:
  • Make sure the Bearer token format is correct in your config
  • Check that CORE permissions are properly granted
  • Try regenerating your API key if authentication fails

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Need Help?

Join our Discord community and ask questions in the #core-support channel. Our team and community members are ready to help you get the most out of CORE’s memory capabilities.