Focus

Sid Sackson's Focus (Parker Brothers' Domination) for the Softmax Coworld platform, on the cogame-parley technology stack. Two cogs, an 8×8 board with the three squares in each corner missing (52 squares), 18 pieces each. Pieces stack; whoever owns the top piece controls the stack. Move the top k pieces of a stack you control exactly k squares orthogonally and land on whatever is there; stacks over five shed from the bottom (your own to your reserve, enemy pieces captured); drop a reserve piece anywhere instead of moving. The last player able to move wins; the ply cap settles on material.

The game is LLM-driven and a policy is just a prompt. Every ply the game server sends the acting seat's policy prompt, the board, and the complete legal-move list to Claude, which answers with what the cog says and which move it makes. Player containers exist only to deliver their prompt over the websocket. A built-in scripted baseline (two-ply minimax on material, captures, and mobility) plays any seat that registers as scripted — and every seat when no LLM credentials are available, so episodes (and offline certification) always complete.

Seats play under anonymous cog names (Sprocket, Gizmo, …): policy display names never reach the agents' prompts, so nobody can meta-game "that seat is the champion". The spectator and replay viewers map the aliases back to policy names; results are reported under policy names.

Layout

• src/focus.nim — entrypoint (Coworld runtime contract, live vs replay mode)
• src/focus/sim.nim — pure rules: board, moves, cap, reserve, endings, replay derivation; shared by server, tests, and the wasm viewer
• src/focus/llm.nim — Claude client + the scripted baseline bot
• src/focus/server.nim — mummy HTTP/WS server (player, global, replay)
• src/focus_player.nim — the prompt-delivery player (PLAYER_PROMPT / PLAYER_SCRIPTED env)
• client/ — shared canvas renderer + global/player/replay pages (the parley broadcast chrome around a Focus board)
• replay-viewer/ — static wasm replay viewer (?replay=<url>)
• tools/build_replay_viewer.sh — Coworld replay-viewer build hook
• data/ — cog sprites and art, borrowed from coworld-ctf (MIT)
• docs/plans/ — the design note this port was built from

Local loop

export PATH="$HOME/.nimby/nim/bin:$PATH"
nimby --global sync nimby.lock                 # fetch pinned packages
# Generate nim.cfg from your nimby package tree (not committed - the
# paths are machine-specific):
rm -f nim.cfg
for pkg in ~/.nimby/pkgs/*; do
  if [ -d "$pkg/src" ]; then echo "--path:\"$pkg/src\"" >> nim.cfg;
  else echo "--path:\"$pkg\"" >> nim.cfg; fi
done
echo '--path:"src"' >> nim.cfg

nim r --path:src tests/test_sim.nim            # rules tests
nim r -d:release --path:src tests/test_bot.nim # scripted-baseline tests
nim c -d:release -o:bin/focus src/focus.nim
nim c -d:release -o:bin/focus-player src/focus_player.nim
# See tmp/config.json for a two-seat fixture; run with COGAME_* env + 2
# players. Export ANTHROPIC_API_KEY for real Claude play; omit for the
# scripted baseline.

Coworld packaging (from a metta checkout):

uv run coworld build --project <this dir> --version 0.1.x
uv run coworld certify <this dir>/dist/coworld_manifest.json
uv run coworld upload-coworld <this dir>/dist/coworld_manifest.json
uv run coworld secret put focus anthropic_api_key <keyfile>   # hosted Claude

Fielding a policy

uv run coworld upload-policy <focus image> --name my-focus \
  --run /bin/focus-player \
  --secret-env PLAYER_PROMPT="Your Focus strategy here."

Or field the scripted tactician: same image, --env PLAYER_SCRIPTED=1.