grain-sdk 0.2.1

Python SDK for Grain — a structured data format for describing AI agents.

grain-sdk

Python SDK for Grain — a structured data format for describing AI agents.

Install

pip install grain-sdk

Usage

from grain import Grain

# Load from file
agent = Grain.load("./my-agent.agent.yaml")

# Generate system prompt
prompt = agent.to_prompt()

# Channel-specific prompt
slack_prompt = agent.to_prompt("slack")

# Clean YAML for LLM consumption (strips metadata)
yaml = agent.to_string()

Create programmatically

from grain import Grain

agent = (
    Grain.create("my-bot", name="My Bot", description="Does helpful things")
    .set_personality("warmth", 0.8)
    .set_personality("confidence", 0.9)
    .add_rule({
        "id": "always-greet",
        "condition": {"type": "always"},
        "action": {"type": "respond-with-style", "style": {"warmth": 0.9}},
    })
    .add_boundary({
        "description": "Never share internal data",
        "category": "data",
        "enforcement": "hard",
        "onViolation": "refuse",
    })
    .add_tool({"id": "search", "usage": "Search knowledge base"})
)

print(agent.to_prompt())

Immutable mutations

Every method returns a new Grain — the original is never modified.

base = Grain.create("my-bot")
with_rule = base.add_rule({"id": "r1", "condition": {"type": "always"}, "action": {"type": "require-confirmation"}})

len(base.rules)       # 0
len(with_rule.rules)  # 1

With any LLM provider

from grain import Grain
from openai import OpenAI

agent = Grain.load("./my-agent.agent.yaml")
client = OpenAI()

response = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "system", "content": agent.to_prompt()},
        {"role": "user", "content": "Hello!"}
    ]
)

Merge and diff

a = Grain.create("bot-a").set_personality("warmth", 0.3)
b = Grain.create("bot-b").set_personality("warmth", 0.9)

merged = a.merge(b)   # b wins on conflicts
changes = a.diff(b)    # {"voice.personality.warmth": {"before": 0.3, "after": 0.9}}

Minimal Spec

specVersion: "1.0"
id: my-bot
version: 1.0.0
meta:
  name: My Bot
  description: Does helpful things

API

Constructors

• Grain.create(id, *, name=None, description="") — Create with defaults
• Grain.from_string(yaml_or_json) — Parse from string
• Grain.load(file_path) — Load from file
• Grain.of(spec_dict) — Wrap a plain dict

Mutations (return new Grain)

• add_rule(rule) / remove_rule(id) / add_rules(rules)
• add_boundary(b) / remove_boundary(desc) / add_boundaries(bs)
• add_tool(t) / remove_tool(name) / add_tools(ts)
• add_skill(s) / remove_skill(name) / add_skills(ss)
• add_expertise(domain, proficiency) / remove_expertise(domain)
• set_personality(dim, value) — validates 0-1 range
• set(path, value) / get(path) — generic deep access
• merge(other) — deep merge, other wins

Properties

• id, name, version — scalars
• personality, rules, boundaries, tools, skills, expertise — copies
• data — raw dict
• is_valid — boolean

Queries

• has_rule(id), has_tool(name), has_skill(name)

Output

• to_string(channel=None) — Clean YAML for LLMs (strips metadata)
• to_prompt(channel=None) — Natural language system prompt
• to_yaml() — Full YAML with all metadata
• to_json() — Full JSON
• validate() — Returns list[ValidationError]
• diff(other) — Structural diff

Presets

• Presets.personality["professional"]
• Presets.personality["friendly"]
• Presets.personality["expert"]
• Presets.personality["creative"]
• Presets.personality["executor"]

License

MIT