Install in Cursor, VSCodium or Windsurf
Those editors read Open VSX, not Microsoft's marketplace. The Open VSX listing is not published yet, so install the same package, byte for byte, from the file below (Extensions → ⋯ → Install from VSIX). Version 0.3.89.
thetacog-mcp-0.3.89.vsix 3890 KB · MIT · 2026-10-16
sha256 1a5fd71e677a7ab710737b550934a98ba9b95cc4ece60b38428ed86ae5c7a18b — the file you get should hash to this; if it does not, do not install it. Machine-readable: /vsx/release.json.
In the editor: Extensions (⇧⌘X / Ctrl+Shift+X) → the ⋯ menu at the top of the panel → Install from VSIX… → pick the file.
From a terminal:
curl -fsSLO https://thetadriven.com/vsx/thetacog-mcp-latest.vsix shasum -a 256 thetacog-mcp-latest.vsix # compare with the hash above cursor --install-extension thetacog-mcp-latest.vsix
(codium / windsurf in place of cursor.) Then reload the window; the ThetaCog sidebar appears in the activity bar.
Search the Marketplace for exactly ThetaCog Steer, or open the listing. Same package, same version.
The measurement is free (MIT); the countersignature is what you pay for. Ten seconds in any terminal, no install: npx thetacog-mcp attest-demo. Source: github.com/wiber/thetacog-mcp.