ARES Business Registry (CZ)

Query Czech ARES business registry by ICO or name with human/JSON/raw outputs, retries, and legal-form decoding.

Use scripts/ares_client.py for ICO lookup and business search.

Working directory

• From workspace root:
  • python3 skills/ares-business-registry/scripts/ares_client.py ...
• From skills/ares-business-registry:
  • python3 scripts/ares_client.py ...

Commands

You can run via the wrapper (recommended):

• ./ares ico <ico>
• ./ares name "NAME" [--nace CODE ...] [--city CITY] [--limit N] [--offset N] [--pick INDEX]

The underlying script also supports:

• python3 scripts/ares_client.py search --name "NAME" ...
• python3 scripts/ares_client.py search --nace CODE [CODE ...] ...
• python3 scripts/ares_client.py search --name "NAME" --nace CODE ... (combined)

Output modes

• default: human-readable summary
• --json: normalized JSON output (stable keys)
• --raw: full raw ARES payload

Examples

# ICO lookup
python3 scripts/ares_client.py ico 27604977
python3 scripts/ares_client.py ico 27604977 --json
python3 scripts/ares_client.py ico 27604977 --raw

# Search by name
python3 scripts/ares_client.py search --name Google
python3 scripts/ares_client.py search --name Google --limit 3 --json
python3 scripts/ares_client.py search --name Google --city Praha --limit 10 --offset 0
python3 scripts/ares_client.py search --name Google --limit 3 --pick 1

# Search by NACE code (CZ-NACE, exactly 5 digits)
python3 scripts/ares_client.py search --nace 47710 --limit 10            # all clothing retailers
python3 scripts/ares_client.py search --nace 47710 --city Praha --json    # clothing retailers in Praha
python3 scripts/ares_client.py search --nace 47710 47910 --limit 5        # clothing retail + mail order

# Combined: name + NACE (AND filter)
python3 scripts/ares_client.py search --name sport --nace 47710 --json    # "sport" in clothing retail

Normalized JSON

• ico output:
  • { "subject": { "name", "ico", "dic", "datumVzniku", "address", "codes", "decoded" } }
• search output:
  • { "query", "total", "items", "picked?" }
  • query includes: name (nullable), city (nullable), nace (nullable array), limit, offset
• dic can be null.
• datumVzniku can be null.

Error JSON contract (--json only)

{
  "error": {
    "code": "validation_error | ares_error | network_error",
    "message": "Human readable message",
    "status": 429,
    "details": {}
  }
}

Validation and exits

• ICO: exactly 8 digits + mod11 checksum
• Search: at least --name (length >= 3) or --nace required; both can be combined
• --nace: exactly 5 digits per code (CZ-NACE format, e.g. 47710); multiple codes accepted (space-separated)
• --limit: default 10, capped to 100
• --offset: must be >= 0
• Exit codes:
  • 0 success
  • 1 validation error
  • 2 ARES non-OK response
  • 3 network/timeout

Caching and decoding

• Legal form decoding (PravniForma) is loaded via POST /ciselniky-nazevniky/vyhledat
• Cache path: skills/ares-business-registry/.cache/pravni_forma.json
• Cache TTL: 24h
• In-memory fallback is used if cache file is stale/unavailable
• Curated overrides:
  • 112 -> s.r.o.
  • 121 -> a.s.
  • 141 -> z.s.
  • 701 -> OSVČ
  • 301 -> s.p.
  • 331 -> p.o.

NACE code search

• --nace sends the czNace field to the ARES complex filter endpoint
• Codes must be exactly 5 digits (CZ-NACE_2025 format)
• Multiple codes can be passed (space-separated) — ARES returns entities matching any of them
• When combined with --name, both filters apply as AND (entities must match name AND have the NACE code)
• NACE-only search (without --name) is supported — useful for browsing all entities in a sector
• Common e-commerce NACE codes:
  • 47710 — Retail sale of clothing
  • 47910 — Retail sale via mail order or internet
  • 47410 — Retail sale of computers and software
  • 47750 — Retail sale of cosmetic and toilet articles
  • 46420 — Wholesale of clothing and footwear
• Full CZ-NACE list: https://www.czso.cz/csu/czso/klasifikace_ekonomickych_cinnosti_cz_nace

City filter limitation

• --city maps to sidlo.nazevObce (structured filter).
• Matching remains best-effort only; ARES server-side matching/ranking can still return records outside the expected municipality.

Retries and rate limits

• HTTP timeout: connect 5s, read 20s
• Retries for transient failures: 429/502/503/504 + network timeout/connection issues
• Backoff: 1s, 2s, 4s
• Honors Retry-After for 429 where provided