clay-borg/simulators/gdl-ggp.md

# GDL / General Game Playing

Stanford Logic Group · `unverified` for current status · `checked` for the
Ludii comparison

## What it optimises for

**Agent generality**: an agent that plays a game it has never seen, given
only the rules in a logical description language.

## How a game is defined

**GDL** — a declarative, logic-programming description of legal moves,
state update and terminal conditions. Verbose relative to Ludii.
`checked` (verbosity claim from the Ludii comparison)

## What it can analyse

Little by design. GGP is a competition framework for agents; the game is
input, not subject.

## What it does not do

Anything designer-facing. **Ludii is measured as materially faster** —
more than six times for Gomoku 15×15, more than twenty for Amazons and
Hex, and over two hundred for Chess. `checked`

## Relevance to clay-borg

**Track A, as the cautionary case.** GDL is the purest form of "define
any game formally" and its cost is speed and readability. It is the
argument for *not* reaching for maximal generality first.

## What to steal

The separation of **rules-as-data** from the agent, which our kernel has
in a weaker form (rules are Rust; only the edition is data).

## What to avoid

Its verbosity, and its framing of the game as an input to an agent rather
than as an artifact under study.

## Open questions

- Whether GGP is still active, and where the community went.

## Sources

- *A note on the empirical comparison of RBG and Ludii*
  (https://arxiv.org/pdf/1910.00309)
- *Game Description Languages: the Good, the Bad, and the Ugly*, Björnsson
  (https://ludii.games/TalksWorkshop/Bjornsson.pdf)
-												simulators/: persist the survey, and let it shrink two of the three tracks

Eight profiles on a common schema, each marking what was checked against a
source this session and what is background recollection. Three are marked
unverified in full — Machinations, the play substrates, most of RBG — and
say so rather than reading as evaluations. Written straight after three
review rounds whose entire yield was claims outrunning what had been
checked, so the confidence rule is the first thing in the README.

The survey changed the plan, which is what a survey is for.

Track C was described in Positioning as open ground. It is not: Browne
published 57 criteria for game quality, and Ai Ai already computes
designer-facing measures — drama, lead changes, branching factor,
completion, duration — from played games. The track becomes adopt, credit
and find the gap. The gap looks real: those measures presume a leader, and
SHARED GROUND has none — Modes.csv gives its tiebreak as "Not applicable".

Track B probably adopts rather than builds. OpenSpiel implements CFR,
best-response and exploitability over games that are simultaneous-move,
imperfect-information and co-operative, which is all four of GROUND's
awkward properties. "Does ATTACK ever pay" is a best-response question,
and we spent three review rounds refining a two-policy sweep for it. The
first Track B task is now one question — is exploitability meaningful for
a co-operative game with a shared threshold — not a build.

The cost of not surveying earlier is therefore measurable, and is recorded
rather than glossed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

											
										
										
											2026-08-08 11:56:27 +02:00
+								# GDL / General Game Playing
 								Stanford Logic Group · `unverified` for current status · `checked` for the
 								Ludii comparison
 								## What it optimises for
 								**Agent generality**: an agent that plays a game it has never seen, given
 								only the rules in a logical description language.
 								## How a game is defined
 								**GDL** — a declarative, logic-programming description of legal moves,
 								state update and terminal conditions. Verbose relative to Ludii.
 								`checked` (verbosity claim from the Ludii comparison)
 								## What it can analyse
 								Little by design. GGP is a competition framework for agents; the game is
 								input, not subject.
 								## What it does not do
 								Anything designer-facing. **Ludii is measured as materially faster** —
 								more than six times for Gomoku 15×15, more than twenty for Amazons and
 								Hex, and over two hundred for Chess. `checked`
 								## Relevance to clay-borg
 								**Track A, as the cautionary case.** GDL is the purest form of "define
 								any game formally" and its cost is speed and readability. It is the
 								argument for *not* reaching for maximal generality first.
 								## What to steal
 								The separation of **rules-as-data** from the agent, which our kernel has
 								in a weaker form (rules are Rust; only the edition is data).
 								## What to avoid
 								Its verbosity, and its framing of the game as an input to an agent rather
 								than as an artifact under study.
 								## Open questions
 								- Whether GGP is still active, and where the community went.
 								## Sources
 								- *A note on the empirical comparison of RBG and Ludii*
 								  (https://arxiv.org/pdf/1910.00309)
 								- *Game Description Languages: the Good, the Bad, and the Ugly*, Björnsson
 								  (https://ludii.games/TalksWorkshop/Bjornsson.pdf)