crs-discipline

crs-discipline is a skill for Claude Code, Codex from buildmoonshot/skillpacks. It costs 66 tokens per session (610 once invoked), scanned A, original, MIT.

A procedure for checking coordinate reference systems, which define how geographic coordinates map to positions on Earth, before combining spatial data.

In plain words
What is it for?
It helps inspect each dataset's CRS, stop when one is undefined, infer it only for confirmation, and reproject data to a suitable common CRS.
Why use it?
It prevents silent errors in map overlays, joins, distances, and areas caused by mismatched or missing coordinate systems.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It helps inspect each dataset's CRS, stop when one is undefined, infer…

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Install with agentmods
npx agentmods add skills/buildmoonshot/skillpacks/crs-discipline
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add buildmoonshot/skillpacks --skill crs-discipline
Clone the repo
git clone --depth 1 https://github.com/buildmoonshot/skillpacks

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for crs-discipline

README.md
[![agentmods](https://agentmods.dev/badge/skills/buildmoonshot/skillpacks/crs-discipline.svg)](https://agentmods.dev/skills/buildmoonshot/skillpacks/crs-discipline)
Your own site
<a href="https://agentmods.dev/skills/buildmoonshot/skillpacks/crs-discipline"><img src="https://agentmods.dev/badge/skills/buildmoonshot/skillpacks/crs-discipline.svg" alt="Measured on agentmods" height="20"></a>
Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 610 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00066 $0.00610
Opus 5 $0.00033 $0.00305
Sonnet 5 $0.00013 $0.00122
Haiku 4.5 $0.00007 $0.00061

Measured 6d ago against content hash b6bce4d5b451, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

crs-discipline scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/gis/beginner/crs-discipline/SKILL.md · 25 lines

How it starts

The opening of the file, as written. The whole thing — 25 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CRS Discipline

Coordinate reference systems are the #1 source of silent, serious GIS errors. Before any spatial operation, know the CRS of every dataset, and make them match.

Rules

  1. Determine the CRS of every input before using it. Check it explicitly — the .prj for a shapefile, the SRID in PostGIS, the spatial reference of a feature class, gdf.crs in GeoPandas. Never start a spatial operation on data whose CRS you haven't confirmed.

  2. Treat an undefined CRS as a stop sign, not a default. Data with no embedded CRS — a shapefile missing its .prj, an SRID of 0 or "unknown" — is the classic trap: it lines up perfectly on the author's machine but is meaningless anywhere else. Do not assume it's WGS84. Infer the likely CRS from the coordinate ranges (values in −180..180 → geographic degrees; large numbers in meters or feet → projected) and confirm with the source before proceeding.

  3. Reproject to a common CRS before combining data. Spatial joins, overlays, clips, and distance/area math require all inputs in the same CRS. Align them first — don't let a library silently compare coordinates in two different systems.

  4. Match the CRS to the operation. Use a geographic CRS (e.g., EPSG:4326) for storage and web display; use an appropriate projected CRS (the right UTM zone, State Plane, or an equal-area projection) for distance, area, and buffer calculations. Measuring length or area in degrees is a bug.

  5. Never confuse "define" with "project." Defining a CRS labels data whose coordinates are already correct but unlabeled. Projecting transforms the coordinates. Mixing them up corrupts data: defining a new CRS onto already-correct data teleports it to the wrong place. This is Define Projection vs Project in ArcPy, ST_SetSRID vs ST_Transform in PostGIS, .set_crs() vs .to_crs() in GeoPandas. Know which one the situation calls for.

Why this matters

A CRS mismatch rarely throws an error — it returns confident, wrong answers: features that don't intersect when they should, distances off by orders of magnitude, layers stacked in the wrong hemisphere. These bugs look like valid output, so they pass review and reach the map, where someone in the field catches them. Thirty seconds of CRS checking prevents an entire class of them.

Read the full file on GitHub · 25 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 25 lines · 66 tokens per session scan A b6bce4d5b451

Subscribe to this mod's changes

crs-discipline is a skill published in the GitHub repository buildmoonshot/skillpacks (2 stars, last pushed 2mo ago), licensed MIT. It adds 66 tokens to every session and 610 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.