Codex

Codex can use Bifrost through the Brokk agent plugin or through a manual MCP server entry. The plugin path is preferred because it includes Bifrost skills and a launcher that resolves the Bifrost binary.

Plugin Install

Add the Brokk marketplace from GitHub, then install Bifrost:

codex plugin marketplace add BrokkAi/bifrost --sparse .agents/plugins --sparse plugins
codex plugin add brokk@bifrost

For local development from a checkout, add this repository root instead:

codex plugin marketplace add "$(pwd)"
codex plugin add brokk@bifrost

For a local checkout build, start Codex with the debug binary selected explicitly:

BIFROST_BINARY_PATH="$(pwd)/target/debug/bifrost" codex

Start a fresh Codex session after installing the plugin so the MCP server configuration is loaded at startup. The packaged plugin uses symbol|extended, so it exposes both symbol navigation and query_code.

Installing the plugin automatically registers its packaged MCP server. Do not add a second manual Bifrost MCP entry for the same plugin. The launcher keeps package command resolution separate from analyzer scope: without an explicit override, Bifrost prefers standard MCP roots. On a rootless connection whose client did not advertise roots, Bifrost offers the codex/sandbox-state-meta extension. Current Codex accepts that capability and supplies the active task directory on each analyzer tool call. Bifrost binds that exact directory, follows later task-directory changes, and never analyzes the plugin cache. BIFROST_WORKSPACE_ROOT remains an authoritative explicit override for fixed-project or older-host configurations.

If the first launch needs to download the pinned Bifrost release, prepare it from a normal host shell before opening that fresh session:

~/.codex/.tmp/marketplaces/bifrost/plugins/bifrost-agent/bin/bifrost-launcher.mjs prepare --json

Wait for "status":"ready". This avoids discovering a download, release-pin, or network failure only after Codex has already fixed the task’s callable tool surface.

Can My Agent Run RQL?

Confirm that query_code appears in the fresh session’s Bifrost tool list. Then ask Codex to call it once with the inline JSON fields {"match":{"kind":"declaration"},"limit":1}. To validate saved RQL, check a workspace file named bifrost-smoke.rql containing (limit 1 (declaration)), then ask Codex to call query_code with {"query_file":"bifrost-smoke.rql"}.

The inline call is canonical JSON, not RQL. MCP accepts RQL only from a workspace .rql file named by query_file. A successful get_summaries or search_symbols call proves symbol navigation but does not prove that query_code is enabled. See MCP query and RQL availability for the full surface matrix and Agent Result Safety before making completeness claims.

Manual MCP Entry

Use a manual MCP entry instead of the plugin-provided server when you want the raw command shape or a different toolset:

codex mcp add bifrost -- bifrost --root /path/to/project --mcp "symbol|extended"
codex mcp list

Use an absolute path to the Bifrost binary if bifrost is not intentionally installed on the host PATH.

Use --mcp core only when you intentionally want navigation without query_code.