Misata

Misata generates consistent, referentially-intact multi-table datasets from a plain-English description, a YAML schema file, or an existing database schema. Every normal generation run can also write an Oracle report: a shareable proof bundle for row counts, referential integrity, constraints, temporal consistency, locale/domain fit, privacy notes, fidelity scores, and reproducibility metadata.

No machine-learning model is required. No real data is needed.

Built for:

• Database seeding — fill dev and staging environments with production-like data
• Integration tests — relational fixtures with FK integrity across every table
• Demos and prototypes — realistic numbers, names, and distributions, no PII
• BI and dashboard development — data shaped like your real domain before launch

Install

pip install misata

Optional extras:

pip install "misata[llm]"        # multi-provider LLM schema generation
pip install "misata[documents]"  # PDF output via weasyprint
pip install "misata[advanced]"   # SDV/CTGAN statistical synthesis
pip install "misata[mcp]"        # MCP server — expose Misata to Claude, Cursor, and other AI agents

Use Misata from Claude / Cursor / Windsurf (MCP)

Misata ships a built-in Model Context Protocol server. Once configured, any MCP-compatible AI assistant can generate realistic synthetic data for you from natural language — no Python required on your end.

1. Install:

pip install "misata[mcp]"

2. Add to Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json):

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

Restart Claude Desktop. Then just ask:

"Generate a fintech dataset with 1 000 customers, payments, and a 2% fraud rate."

"Show me what tables Misata would produce for an HR system with 200 employees."

"I need SaaS data: MRR from $50k in January, doubled by December, with a Q3 slump."

Claude calls Misata, writes CSVs to disk, and returns the file paths plus a preview of each table. See the MCP guide for Cursor/Windsurf/Zed setup and all five available tools.

Quick start

misata generate \
  --story "Brazilian fintech with R$ payments, CPF verification, and 3% fraud" \
  --rows 1000 \
  --output-dir ./demo_data

# Writes CSVs plus:
# ./demo_data/oracle_report.json

import misata

# One sentence → multi-table DataFrame dict
tables = misata.generate("A SaaS company with 5k users, monthly subscriptions, and 20% churn")

print(tables["users"].head())
print(tables["subscriptions"].head())

# Or from the CLI
misata generate --story "A SaaS company with 5k users and 20% churn" --rows 5000

Misata Oracle

The Oracle report is Misata's proof layer. It separates hard guarantees from advisory realism checks so generated data can be trusted in CI, demos, notebooks, and research comparisons.

Guaranteed checks:

• referential integrity across configured relationships
• requested row-count fulfillment
• schema validation and configured constraints
• deterministic reproducibility when a seed is set

Advisory checks:

• quality score and plausibility warnings
• privacy heuristics
• schema-vs-output fidelity score
• locale/domain fit for countries, cities, phone prefixes, and national IDs
• data-card metadata

import misata

schema = misata.parse("Brazilian fintech with CPF verification", rows=1000)
tables = misata.generate_from_schema(schema)
oracle = misata.build_oracle_report(tables, schema, seed=schema.seed)

print(oracle["passed"])
print(oracle["advisory"]["locale_domain_fit"]["locale"])

Six ways to generate data

1. Plain English — no config required

tables = misata.generate("A fintech startup with 10k customers, fraud rate 3%, and IBAN accounts")

Misata reads the story, infers domain (fintech), scale (10 000 rows), and column semantics (fraud flag, IBAN format) — no schema authoring needed.

2. YAML schema-as-code — commit it to git

misata init           # scaffolds misata.yaml in the current directory
misata generate       # reads misata.yaml automatically

# misata.yaml
name: my-app
seed: 42

tables:
  users:
    rows: 1000
    columns:
      user_id: { type: int, unique: true }
      email:   { type: text, text_type: email }
      plan:    { type: categorical, choices: [free, pro, enterprise] }

  orders:
    rows: 5000
    columns:
      order_id: { type: int, unique: true }
      user_id:  { type: foreign_key }
      amount:   { type: float, min: 5.0, max: 500.0 }

relationships:
  - "users.user_id → orders.user_id"

constraints:
  - name: amount_above_cost
    table: orders
    type: inequality
    column_a: amount
    operator: ">"
    column_b: cost

schema = misata.load_yaml_schema("misata.yaml")
tables = misata.generate_from_schema(schema)

3. Seed an existing database directly

from misata import schema_from_db, generate_from_schema, seed_database

# Introspect the live schema — no manual column definitions
schema = schema_from_db("postgresql://user:pass@localhost/myapp")
tables = generate_from_schema(schema)

# Seed it back — insert order respects FK dependencies automatically
report = seed_database(tables, "postgresql://user:pass@localhost/myapp_dev")
# SeedReport: seeded 6 tables, 47,300 rows in 1.2s

# One-command workflow
misata init --db postgresql://user:pass@localhost/myapp   # writes misata.yaml
misata generate --db-url postgresql://user:pass@localhost/myapp_dev --db-create

SQLAlchemy models are supported too:

from misata import seed_from_sqlalchemy_models
from myapp.models import Base

report = seed_from_sqlalchemy_models(Base, db_url="sqlite:///test.db", row_count=500, create_tables=True)

4. Python dict schema

schema = misata.from_dict_schema({
    "customers": {
        "id":    {"type": "integer", "primary_key": True},
        "email": {"type": "email"},
        "plan":  {"type": "string", "enum": ["free", "pro", "enterprise"]},
    },
    "orders": {
        "id":          {"type": "integer", "primary_key": True},
        "customer_id": {"type": "integer", "foreign_key": {"table": "customers", "column": "id"}},
        "amount":      {"type": "float", "min": 1.0, "max": 999.0},
    },
}, row_count=5_000)

tables = misata.generate_from_schema(schema)

5. LLM-assisted generation — richer semantics, optional

from misata import LLMSchemaGenerator

gen = LLMSchemaGenerator(provider="groq")          # free tier, fast
# gen = LLMSchemaGenerator(provider="anthropic")   # Claude
# gen = LLMSchemaGenerator(provider="ollama", model="llama3")  # fully local, no API key

schema = gen.generate_from_story(
    "A fraud detection dataset — 2% positive rate, FICO scores, transaction velocity features"
)
tables = misata.generate_from_schema(schema)

Requires pip install "misata[llm]" plus one of GROQ_API_KEY, OPENAI_API_KEY, ANTHROPIC_API_KEY, GOOGLE_API_KEY.

6. Incremental generation — grow a dataset without re-seeding

tables = misata.generate("A fintech company with 1000 customers", seed=1)

# Add 1 000 more rows — IDs auto-offset, FK integrity maintained across both batches
tables = misata.generate_more(tables, schema, n=1000, seed=2)
print(len(tables["customers"]))  # 2000

Localisation

Misata automatically detects the country context from your story and generates statistically accurate data for that locale — the right names, salary distributions, national ID formats, currencies, postcodes, and company naming conventions.

# Locale is detected automatically — no extra flag needed
tables = misata.generate("German SaaS company in Berlin with 2k enterprise customers")
# → names from de_DE Faker pool, salary ~ lognormal(μ=10.71, σ=0.5) ≈ €45k median,
#   postcodes are 5-digit, company names end in GmbH/AG/UG

tables = misata.generate("Brazilian fintech with R$ payments and CPF verification, 50k users")
# → pt_BR names, salary median ~BRL 33.6k, national IDs match CPF format ###.###.###-##

tables = misata.generate("Indian startup in Bangalore with ₹ salary bands and Aadhaar KYC")
# → hi_IN names, salary median ~₹350k/yr, national IDs match Aadhaar 12-digit format

Force or override a locale explicitly:

schema = misata.parse("An ecommerce store with 10k orders")
tables = misata.generate_from_schema(schema)  # defaults to en_US

# CLI
misata generate --story "Ecommerce store" --locale ja_JP

15 built-in locales

Each pack carries real salary distributions (median and lognormal priors), age distributions, top-ranked cities, phone-number prefixes, postcode patterns, company suffixes, and VAT rates — sourced from OECD, World Bank, ILO, and national statistics offices (2023–24 data).

# Inspect a locale pack directly
pack = misata.get_locale_pack("de_DE")
print(pack.salary_median)       # 45000
print(pack.currency_symbol)     # €
print(pack.top_cities[:3])      # ['Berlin', 'Hamburg', 'Munich']
print(pack.company_suffixes)    # ['GmbH', 'AG', 'UG', 'KG', 'e.K.']

# Auto-detect from a story
locale = misata.detect_locale("South Korean company in Seoul with KRW salaries")
# → "ko_KR"

Constraints

Enforce business rules that survive every row of generation:

from misata.constraints import (
    InequalityConstraint,   # price > cost on every row
    ColumnRangeConstraint,  # min_price <= price <= max_price
    RatioConstraint,        # 70% free / 30% pro
    UniqueConstraint,       # no duplicate (user_id, date) pairs
    SumConstraint,          # total_hours per employee per day <= 8
    NotNullConstraint,      # no nulls in required columns
)

c = InequalityConstraint("price", ">", "cost")
df = c.apply(df)

Constraints can also be declared in misata.yaml — they run at generation time, not as a post-processing step.

Export

misata.to_parquet(tables, "data/")
misata.to_duckdb(tables, "data/dataset.duckdb")
misata.to_jsonl(tables, "data/")

Document generation

Render one document per row from any table — useful for demo datasets that need to look real end-to-end:

# Built-in templates: invoice, patient_report, transaction_receipt, user_profile
paths = misata.generate_documents(
    tables, "invoice", table="orders", output_dir="/tmp/invoices", format="html"
)
# format="pdf" requires: pip install "misata[documents]"

# Custom Jinja2 template
tmpl = "<h1>Order #{{ order_id }}</h1><p>Amount: ${{ amount }}</p>"
paths = misata.generate_documents(tables, tmpl, table="orders", output_dir="/tmp/custom")

Quality and privacy analysis

bundle = misata.analyze_generation(tables, schema)

print(bundle.data_card.summary())        # row counts, null rates, type distribution
print(bundle.fidelity_report.score)      # 0–1 statistical fidelity score vs. schema intent
print(bundle.privacy_report.pii_risk)    # column-level PII exposure analysis

Supported domains

18 built-in domain schemas — each generates a fully relational, multi-table dataset with realistic distributions, FK integrity, and domain-appropriate column semantics.

No keyword match → generic single-table schema with smart column inference.

How it works

story / YAML / dict / DB introspection / MCP tool call
              ↓
        StoryParser  ·  locale detection  ·  load_yaml_schema  ·  schema_from_db
              ↓
        DetectionReport  (domain, confidence, near_misses, table_preview, warnings)
              ↓
        SchemaConfig  ←  validate_schema() catches issues before any rows are generated
              ↓
        DataSimulator
          ├─ topological sort (FK dependency order)
          ├─ domain priors  →  locale priors (salary, age, monetary)
          ├─ constraint engine (inequality, range, ratio, sum, unique)
          ├─ outcome curves (monthly targets from narrative control points)
          ├─ Iman-Conover correlation engine (Cholesky, preserves marginals)
          └─ RealisticTextGenerator (Faker locale + Kaggle vocabulary assets)
              ↓
        {table_name: DataFrame}
              ↓
        seed_database  ·  to_parquet  ·  to_duckdb  ·  generate_documents  ·  MCP CSV output

Domain priors — monetary columns get log-normal distributions. Categoricals use Zipf sampling. Blood types, country distributions, and salary bands reflect real-world statistics.

Locale priors — salary and age distributions are overridden with country-specific lognormal/normal parameters sourced from national statistics. "Brazilian fintech" in your story means salaries are sampled from the BRL distribution, not the USD one.

Outcome curves — natural-language narrative is parsed into exact monthly control points. Named events, quarters, and multipliers all work:

# All of these produce precise, shaped outcome curves:
misata.generate("SaaS mrr from $50k in Jan to $200k in Dec, with a Q3 slump")
misata.generate("Ecommerce orders, Black Friday spike, Christmas peak")
misata.generate("SaaS startup — MRR 10x growth over the year")
misata.generate("Fintech payments — strong Q4, dip in Q1")

Realism rules — cost is always less than price. delivered_at is always after shipped_at. hire_date is after date_of_birth + 18 years and never in the future. tenure_years is derived on the same row from hire_date. Email addresses derive from first and last name columns.

What makes Misata different

Faker generates individual fake values — not relational, no schema, no statistical accuracy. Synth excels at schema-as-code git workflows; limited distribution control. syda uses an LLM for every row — semantically rich but expensive, slow, and requires an API key. SDV learns from real data — a different problem (you need real data first). Misata generates from intent, offline by default, seeds databases directly, and now brings country-accurate statistics to every column automatically.

Performance

Measured on Apple M-series (single core, no GPU):

Contributing

git clone https://github.com/rasinmuhammed/misata
cd misata
pip install -e ".[dev]"
pytest tests/

Issues and PRs welcome — github.com/rasinmuhammed/misata/issues