Geofeed Tuner – Create Better IP Geolocation Feeds

This skill helps you create and improve IP geolocation feeds in CSV format by:

• Ensuring your CSV is well-formed and consistent
• Checking alignment with RFC 8805 (the industry standard)
• Applying opinionated best practices learned from real-world deployments
• Suggesting improvements for accuracy, completeness, and privacy

When to Use This Skill

• Use this skill when a user asks for help creating, improving, or publishing an IP geolocation feed file in CSV format.
• Use it to tune and troubleshoot CSV geolocation feeds — catching errors, suggesting improvements, and ensuring real-world usability beyond RFC compliance.
• Intended audience:
  • Network operators, administrators, and engineers responsible for publicly routable IP address space
  • Organizations such as ISPs, mobile carriers, cloud providers, hosting and colocation companies, Internet Exchange operators, and satellite internet providers
• Do not use this skill for private or internal IP address management; it applies only to publicly routable IP addresses.

Prerequisites

• Python 3 is required.

Directory Structure and File Management

This skill uses a clear separation between distribution files (read-only) and working files (generated at runtime).

Read-Only Directories (Do Not Modify)

The following directories contain static distribution assets. Do not create, modify, or delete files in these directories:

Working Directories (Generated Content)

All generated, temporary, and output files go in these directories:

File Management Rules

1. Never write to assets/, references/, or scripts/ — these are part of the skill distribution and must remain unchanged.
2. All downloaded input files (from remote URLs) must be saved to ./run/data/.
3. All generated HTML reports must be saved to ./run/report/.
4. All generated Python scripts must be saved to ./run/.
5. The run/ directory may be cleared between sessions; do not store permanent data there.
6. Working directory for execution: All generated scripts in ./run/ must be executed with the skill root directory (the directory containing SKILL.md) as the current working directory, so that relative paths like assets/iso3166-1.json and ./run/data/report-data.json resolve correctly. Do not cd into ./run/ before running scripts.

Processing Pipeline: Sequential Phase Execution

All phases must be executed in order, from Phase 1 through Phase 6. Each phase depends on the successful completion of the previous phase. For example, structure checks must complete before quality analysis can run.

The phases are summarized below. The agent must follow the detailed steps outlined further in each phase section.

Do not skip phases. Each phase provides critical checks or data transformations required by subsequent stages.

Execution Plan Rules

Before executing each phase, the agent MUST generate a visible TODO checklist.

The plan MUST:

• Appear at the very start of the phase
• List every step in order
• Use a checkbox format
• Be updated live as steps complete

Phase 1: Understand the Standard

The key requirements from RFC 8805 that this skill enforces are summarized below. Use this summary as your working reference. Only consult the full RFC 8805 text for edge cases, ambiguous situations, or when the user asks a standards question not covered here.

RFC 8805 Key Facts

Purpose: A self-published IP geolocation feed lets network operators publish authoritative location data for their IP address space in a simple CSV format, allowing geolocation providers to incorporate operator-supplied corrections.

CSV Column Order (Sections 2.1.1.1–2.1.1.5):

Structural rules:

• Files may contain comment lines beginning with # (including the header, if present).
• A header row is optional; if present, it is treated as a comment if it starts with #.
• Files must be encoded in UTF-8.
• Subnet host bits must not be set (i.e., 192.168.1.1/24 is invalid; use 192.168.1.0/24).
• Applies only to globally routable unicast addresses — not private, loopback, link-local, or multicast space.

Do-not-geolocate: An entry with an empty alpha2code or case-insensitive ZZ (irrespective of values of region/city) is an explicit signal that the operator does not want geolocation applied to that prefix.

Postal codes deprecated (Section 2.1.1.5): The fifth column must not contain postal or ZIP codes. They are too fine-grained for IP-range mapping and raise privacy concerns.

Phase 2: Gather Input

• If the user has not already provided a list of IP subnets or ranges (sometimes referred to as inetnum or inet6num), prompt them to supply it. Accepted input formats:

  • Text pasted into the chat
  • A local CSV file
  • A remote URL pointing to a CSV file

• If the input is a remote URL:

  • Attempt to download the CSV file to ./run/data/ before processing.
  • On HTTP error (4xx, 5xx, timeout, or redirect loop), stop immediately and report to the user: Feed URL is not reachable: HTTP {status_code}. Please verify the URL is publicly accessible.
  • Do not proceed to Phase 3 with an incomplete or empty download.

• If the input is a local file, process it directly without downloading.

• Encoding detection and normalization:

  1. Attempt to read the file as UTF-8 first.
  2. If a UnicodeDecodeError is raised, try utf-8-sig (UTF-8 with BOM), then latin-1.
  3. Once successfully decoded, re-encode and write the working copy as UTF-8.
  4. If no encoding succeeds, stop and report: Unable to decode input file. Please save it as UTF-8 and try again.

Phase 3: Checks & Suggestions

Execution Rules

• Generate a script for this phase.
• Do NOT combine this phase with others.
• Do NOT precompute future-phase data.
• Store the output as a JSON file at: ./run/data/report-data.json

Schema Definition

The JSON structure below is IMMUTABLE during Phase 3. Phase 4 will later add a TunedEntry object to each object in Entries — this is the only permitted schema extension and happens in a separate phase.

JSON keys map directly to template placeholders like {{.CountryCode}}, {{.HasError}}, etc.

{
  "InputFile": "",
  "Timestamp": 0,

  "TotalEntries": 0,
  "IpV4Entries": 0,
  "IpV6Entries": 0,
  "InvalidEntries": 0,

  "Errors": 0,
  "Warnings": 0,
  "OK": 0,
  "Suggestions": 0,

  "CityLevelAccuracy": 0,
  "RegionLevelAccuracy": 0,
  "CountryLevelAccuracy": 0,
  "DoNotGeolocate": 0,

  "Entries": [
    {
      "Line": 0,
      "IPPrefix": "",
      "CountryCode": "",
      "RegionCode": "",
      "City": "",

      "Status": "",
      "IPVersion": "",

      "Messages": [
        {
          "ID": "",
          "Type": "",
          "Text": "",
          "Checked": false
        }
      ],

      "HasError": false,
      "HasWarning": false,
      "HasSuggestion": false,
      "DoNotGeolocate": false,
      "GeocodingHint": "",
      "Tunable": false
    }
  ]
}

Field definitions:

Top-level metadata:

• InputFile: The original input source, either a local filename or a remote URL.
• Timestamp: Milliseconds since Unix epoch when the tuning was performed.
• TotalEntries: Total number of data rows processed (excluding comment and blank lines).
• IpV4Entries: Count of entries that are IPv4 subnets.
• IpV6Entries: Count of entries that are IPv6 subnets.
• InvalidEntries: Count of entries that failed IP prefix parsing and CSV parsing.
• Errors: Total entries whose Status is ERROR.
• Warnings: Total entries whose Status is WARNING.
• OK: Total entries whose Status is OK.
• Suggestions: Total entries whose Status is SUGGESTION.
• CityLevelAccuracy: Count of valid entries where City is non-empty.
• RegionLevelAccuracy: Count of valid entries where RegionCode is non-empty and City is empty.
• CountryLevelAccuracy: Count of valid entries where CountryCode is non-empty, RegionCode is empty, and City is empty.
• DoNotGeolocate (metadata): Count of valid entries where CountryCode, RegionCode, and City are all empty.

Entry fields:

• Entries: Array of objects, one per data row, with the following per-entry fields:
  • Line: 1-based line number in the original CSV (counting all lines including comments and blanks).
  • IPPrefix: The normalized IP prefix in CIDR slash notation.
  • CountryCode: The ISO 3166-1 alpha-2 country code, or empty string.
  • RegionCode: The ISO 3166-2 region code (e.g., US-CA), or empty string.
  • City: The city name, or empty string.
  • Status: Highest severity assigned: ERROR > WARNING > SUGGESTION > OK.
  • IPVersion: "IPv4" or "IPv6" based on the parsed IP prefix.
  • Messages: Array of message objects, each with:
    • ID: String identifier from the Validation Rules Reference table below (e.g., "1101", "3301").
    • Type: The severity type: "ERROR", "WARNING", or "SUGGESTION".
    • Text: The human-readable validation message string.
    • Checked: true if the validation rule is auto-tunable (Tunable: true in the reference table), false otherwise. Controls whether the checkbox in the report is checked or disabled.
  • HasError: true if any message has Type "ERROR".
  • HasWarning: true if any message has Type "WARNING".
  • HasSuggestion: true if any message has Type "SUGGESTION".
  • DoNotGeolocate (entry): true if CountryCode is empty or "ZZ" — the entry is an explicit do-not-geolocate signal.
  • GeocodingHint: Always empty string "" in Phase 3. Reserved for future use.
  • Tunable: true if any message in the entry has Checked: true. Computed as logical OR across all messages' Checked values. This flag drives the "Tune" button visibility in the report.

Validation Rules Reference

When adding messages to an entry, use the ID, Type, Text, and Checked values from this table.