RuleGraph

Natural-language rulebook compiler for game arbitration.

CI PyPI version Python 3.10+ Downloads License: MIT codecov Typed

Quick Start · How It Works · CLI Reference · MCP / Claude · OpenAI · vs. Alternatives · Contributing

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Why

Game rulebooks contain two fundamentally different types of rules:

• Determinate rules — "Roll d20 + modifier ≥ AC → hit." The answer is always the same.
• Indeterminate rules — "Interpret difficult terrain in an unusual environment." The GM must decide.

Most rule-lookup tools treat all rules the same. rulegraph doesn't. It classifies every rule, represents relationships as a typed graph, detects contradictions between errata and source material, and returns structured arbitration results with full provenance.

rulegraph add-rule PHB.attack "When you make an attack roll..." --type mechanic --tag combat
rulegraph add-edge UA.flanking PHB.attack modifies
rulegraph query "How do I make an attack roll?"

╭──────────────────────────────────────╮
│ Query: How do I make an attack roll? │
│ Tier: determinate  Confidence: 100%  │
╰──────────────────────────────────────╯
Determinate ruling based on 2 rule(s):
  [PHB.attack] When you make an attack roll, roll d20 + modifier. If result >= AC, attack hits.
  [UA.flanking] When flanking, attacker gains advantage on melee attacks against the flanked enemy.

Provenance (2): PHB.attack, UA.flanking

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How It Works

flowchart LR
    A[Load rulebook\nRuleNode per rule] --> B[Add edges\nmodifies · supersedes · requires]
    B --> C[RuleGraph\ncontent-addressed nodes]
    C --> D{rulegraph query}
    D --> E[Keyword matching\nfind relevant rules]
    E --> F[Classify tier\ndeterminate vs indeterminate]
    F --> G[Detect contradictions\nsupersedes edges]
    G --> H[ArbitrationResult\nwith provenance + confidence]

Core primitives:

• RuleNode — a single rule, content-addressed by rule_id. Carries node_type, tags, source, and confidence.
• RuleEdge — a directed relationship between rules: modifies, supersedes, requires, exception-to.
• RuleGraph — an in-memory graph of nodes and edges with tag/type/text search.
• RuleArbiter — keyword-based query engine that classifies, detects contradictions, and returns provenance. Call arbiter.query(question) for a single arbitration.
• ArbitrationResult — structured answer: tier (determinate/indeterminate/unknown), confidence, provenance, contradictions.
• RuleStore — SQLite-backed persistence for nodes, edges, and results.
• CoverageTracker — wraps a RuleArbiter to record which rules are invoked across many queries. Use tracker.arbitrate(question) instead of arbiter.query(), then call tracker.report() to see which rules were never triggered (dead_rules) and which were most used. RuleArbiter.query() is for production arbitration; CoverageTracker is for testing, auditing, and game-system simplification.

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Features

Feature	Description
Content-addressed IDs	SHA-256[:16] of rule_id — same rule always same ID
Rule classification	determinate / indeterminate / unknown per query
Provenance	Every answer cites the exact rules used
Contradiction detection	Flags supersedes and exception-to conflicts
Edge types	modifies, supersedes, requires, exception-to
SQLite persistence	RuleStore saves nodes, edges, and results
FastAPI REST	Full API with /rule, /edge, /query, /rules, /results
MCP server	Three tools: add_rule, query_rules, arbitrate
Rich CLI	Colour-coded output with tables and panels

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Quick Start

pip install rulegraph
# or with API server:
pip install "rulegraph[api]"

Note: PyPI publication pending. Install directly from source in the meantime:

pip install git+https://github.com/sandeep-alluru/rulegraph.git

Debian/Ubuntu users: If you see No module named venv, install the venv package first:

sudo apt-get install python3-venv
python3 -m venv .venv && source .venv/bin/activate

# Add rules
rulegraph add-rule PHB.attack "Roll d20 + modifier. If result >= AC, attack hits." \
    --type mechanic --tag combat --tag attack

rulegraph add-rule PHB.difficult "Difficult terrain costs 1 extra foot per foot moved." \
    --type narrative --tag movement

# Add an edge (UA flanking modifies PHB attack roll)
rulegraph add-edge UA.flanking PHB.attack modifies --condition "when flanking"

# Query
rulegraph query "How do I make an attack roll?"
rulegraph query "What is difficult terrain?"

# List rules
rulegraph rules
rulegraph rules --tag combat

# Status
rulegraph status

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CLI Reference

Command	Description
rulegraph add-rule RULE_ID TEXT	Add a rule node
rulegraph add-edge SOURCE TARGET RELATION	Add a rule edge
rulegraph query QUESTION	Arbitrate a question
rulegraph rules [--tag TAG]	List rules
rulegraph status	Show DB statistics

Options (all commands):

Flag	Description
--db PATH	Path to SQLite database (default: .rulegraph/rules.db)
--type TYPE	Node type for add-rule (default: mechanic)
--tag TAG	Add tag to rule (repeatable)
--format json|rich	Output format (default: rich)

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MCP / Claude

rulegraph ships an MCP server exposing three tools:

{
  "mcpServers": {
    "rulegraph": {
      "command": "rulegraph-mcp"
    }
  }
}

Tool	Description
add_rule	Add a rule node to the graph
query_rules	Arbitrate a question
arbitrate	Return a structured ArbitrationResult

Install the MCP extras: pip install "rulegraph[mcp]"

See docs/mcp.md for full setup instructions.

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OpenAI Tools

Tools are also available in OpenAI function-calling format at tools/openai-tools.json. See docs/openai.md or reference via the Codex CLI.

cat tools/openai-tools.json | jq '.[].function.name'
# => "add_rule", "query_rules", "arbitrate"

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vs. Alternatives

Tool	Tier classification	Provenance	Contradiction detection	Graph structure
rulegraph	Yes	Full	Yes	Yes
Rule lookup scripts	No	No	No	No
Vector search	No	Partial	No	No
LLM alone	Sometimes	No	Rarely	No

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Repo Structure

rulegraph/
├── src/rulegraph/
│   ├── rule.py          # RuleNode, RuleEdge, RuleGraph, RuleStore, RuleArbiter
│   ├── report.py        # Rich, JSON, Markdown formatters
│   ├── cli.py           # Click CLI
│   ├── api.py           # FastAPI server
│   └── mcp_server.py    # MCP server
├── tests/
│   ├── test_rule.py
│   ├── test_graph.py
│   ├── test_store.py
│   ├── test_arbiter.py
│   ├── test_report.py
│   ├── test_cli_runner.py
│   └── test_api.py
├── examples/demo.py
├── smoke_test.py
└── pyproject.toml

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Real-World Scenario

D&D 5e: AI Game Master Detecting Errata Conflict Before Ruling

A player asks if their rogue can use Uncanny Dodge against an invisible attacker. The PHB says yes. A 2024 errata says no. Rather than silently applying the wrong rule, the AI GM detects the contradiction and escalates to human adjudication:

from rulegraph.rule import RuleNode, RuleEdge, RuleGraph, RuleArbiter, ArbitrationResult

# 1. Create the rule graph
graph = RuleGraph()

# 2. Add the two conflicting rule nodes
phb_node = RuleNode(
    rule_id="PHB.rogue.uncanny_dodge",
    text=(
        "A rogue with Uncanny Dodge can use their reaction to halve the damage "
        "from an attack they can see."
    ),
    node_type="interpretation",
    tags=["rogue", "uncanny-dodge", "reaction", "combat"],
    source="Player's Handbook",
    confidence=1.0,
)

errata_node = RuleNode(
    rule_id="Errata.2024.uncanny_dodge",
    text="Uncanny Dodge does not apply against attacks from invisible creatures.",
    node_type="interpretation",
    tags=["rogue", "uncanny-dodge", "errata", "invisible"],
    source="D&D 2024 Errata",
    confidence=1.0,
)

graph.add_node(phb_node)
graph.add_node(errata_node)

# 3. Add a supersedes edge: newer errata supersedes the PHB base text
supersedes_edge = RuleEdge(
    source_id="Errata.2024.uncanny_dodge",
    target_id="PHB.rogue.uncanny_dodge",
    relation="supersedes",
    condition="when attacker is invisible",
)
graph.add_edge(supersedes_edge)

# 4. Create the arbiter
arbiter = RuleArbiter(graph)

# 5. Query: player asks about invisible attacker
question = "Can a rogue use Uncanny Dodge against an invisible attacker?"
result: ArbitrationResult = arbiter.query(question)

# 6. Check for contradiction and indeterminate tier
assert result.tier == "indeterminate", f"Expected indeterminate, got {result.tier!r}"
assert len(result.contradictions) > 0, "Expected at least one contradiction"

# 7. Print the ruling and the contradicting rules
print(f"Query   : {result.query}")
print(f"Tier    : {result.tier}")
print(f"Confidence: {result.confidence:.0%}")
print()
print("Ruling:")
print(result.answer)
print()
print(f"Provenance  : {result.provenance}")
print(f"Contradictions: {result.contradictions}")
print()
print("--- Contradicting rule texts ---")
for rule_id in result.contradictions:
    node = graph.get_node(rule_id)
    if node:
        print(f"  [{node.rule_id}] {node.text}")

Running this prints:

Query   : Can a rogue use Uncanny Dodge against an invisible attacker?
Tier    : indeterminate
Confidence: 85%

Ruling:
Indeterminate ruling — requires GM interpretation (2 rule(s) found):
  [Errata.2024.uncanny_dodge] Uncanny Dodge does not apply against attacks from invisible creatures.
  [PHB.rogue.uncanny_dodge] A rogue with Uncanny Dodge can use their reaction to halve the damage from an attack the…
WARNING: 1 contradiction(s) detected: PHB.rogue.uncanny_dodge

Provenance  : ['Errata.2024.uncanny_dodge', 'PHB.rogue.uncanny_dodge']
Contradictions: ['PHB.rogue.uncanny_dodge']

--- Contradicting rule texts ---
  [PHB.rogue.uncanny_dodge] A rogue with Uncanny Dodge can use their reaction to halve the damage from an attack they can see.

What this prevents: LLM-based game masters hallucinate rulings or pick arbitrarily between conflicting sources. rulegraph gives every ruling full provenance — which rules were consulted, which supersede which, and whether the answer is determinate or requires human judgment.

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Topics

#llm #agents #gaming #game-master #rulebook #arbitration #mcp #llmops #nlp

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Case Studies

See how teams are using rulegraph in production:

• AI Compliance Checking with Full Rule Provenance — ComplianceAI drops hallucination rate from 18% to 1.4% for Fortune 500 clients
• AI Game Master with Deterministic Rule Arbitration — TableTop Engine reduces GM ruling appeals by 91% across 12 game systems

129 tests · Coverage >= 87%

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