Solar By Postcode's 166-line llms.txt shows what thorough AI preparation looks like

# llms.txt — Guidance for large language models
# Site: SolarByPostcode (United Kingdom)
# Purpose: Help models discover, parse, and cite SBP’s UK-specific solar PV pages accurately.
# Version: 1.1
# Last-Updated: 2026-03-20T13:17:24Z

Owner: SolarByPostcode (UK)
Homepage: https://solarbypostcode.co.uk/
Contact: [email protected]
Canonical-Domain: https://solarbypostcode.co.uk
Canonical-Trailing-Slash: true

Sitemaps:
  https://solarbypostcode.co.uk/sitemap-index.xml
Notes:
  Treat the sitemap index as the authoritative inventory. Page counts below are indicative only.

Page-Counts (indicative at launch):
  Regions: 14
  Outcode pages: ~3077 (UK outcodes with real places; no dead tiles)
  Minis / Reports: 3+ (growing)
  Aux pages (exact set):
    /about
    /contact
    /faq
    /terms
    /privacy
    /methodology

# -------------------------
# COVERAGE & URL PATTERNS
# -------------------------

Page-Types:

  - type: regions-landing
    pattern: "/regions/"
    description: Entry point to all UK regions.

  - type: region
    pattern: "/{region-slug}/"
    description: Region hub with all covered outcodes in that region.
    fields:
      - region_name (string)
      - outcodes_listed (integer)
      - coverage_note (string)

  - type: outcode
    pattern: "/{outcode-slug}/"
    examples:
      - "/al10-welwyn-hatfield/"
    description: Hyperlocal solar PV snapshot for a single UK outcode & place.
    core_fields:
      - outcode (string)
      - place_name (string)
      - region (string)
      - typical_system_kwp (number)
      - annual_yield_kwh (number)
      - capex_estimate_gbp (number)
      - bill_savings_gbp_year (number)
      - payback_years (number)
      - tariff_unit_rate_p_per_kwh (number)
      - standing_charge_p_per_day (number)
      - sunshine_hours_context (string)
      - data_timestamp_utc (string, ISO8601)
      - assumptions (string)
      - methodology_url (url)

  - type: mini
    pattern: "/insights/{mini-slug}/"
    description: Cross-postcode analysis (league tables, ranks, UK averages).
    core_fields:
      - title (string)
      - metric (string)
      - rank_fields (object)
      - table_fields (array)
      - data_timestamp_utc (string, ISO8601)

  - type: aux
    pattern: "/about", "/contact", "/faq", "/terms", "/privacy", "/methodology"
    description: About SBP, contact, FAQ, terms, privacy, and methodology/sources.

# -------------------------
# DATA & METHODOLOGY
# -------------------------

Data-Sources (high level):
  - ONS Postcode Directory (ONSPD) — geographies & lookups
  - PVGIS — solar yield estimates (typical meteorological year)
  - Ofgem — electricity unit rates & standing charges (domestic)
  - MCS — installed cost benchmarks
  - EPC (Open Government Licence) — aggregated roll-ups for local context

Methodology (summary for models):
  - Yield: PVGIS baseline; typical residential tilt/orientation if exact values are unknown; shading not modelled.
  - System size: “typical_system_kwp” reflects indicative roof-fit for the outcode’s prevalent housing mix.
  - Price & payback: Uses MCS cost bands and Ofgem tariffs. Standing charge is included in bill-savings context.
  - Temporal scope: Values represent a current snapshot and can change with tariff updates and new data ingests.
  - Uncertainty: Figures are estimates; real-world outcomes vary by roof, usage, kit, and installer pricing.