principle-boundary-discipline SKILL.md skillA

This file is byte-identical to the first copy the registry indexed, one of 6 indexed copies. Same content hash, so the same checks give both the same grade.

principle-boundary-discipline from backnotprop/pstack is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

mdr add backnotprop/pstack/principle-boundary-discipline@git:20260914.55bfdc2

Pins git:20260914.55bfdc2 in mdr.lock. Pin the fingerprint instead.

Audit grade

A, 17 of 17 checks passed

Kind

SKILL.md skill

Repository

backnotprop/pstack

Path

skills/principle-boundary-discipline/SKILL.md

Versions recorded

3

Latest version

git:20260914.55bfdc2, committed Sep 14, 2026

First version recorded

May 27, 2026

Size

1,883 bytes

Repository stars

3,337

License

MIT

Apply when wiring validation, error handling, or framework adapters. Concentrate guards at system boundaries (CLI, config, network, external APIs); trust internal types and keep business logic in pure functions.

Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.

What the file says

# Boundary Discipline

Place validation, type narrowing, and error handling at system boundaries. Trust internal code unconditionally. Business logic lives in pure functions. The shell is thin and mechanical.

**Why:** Scattered validation is noisy, redundant, and gives a false sense of safety. Keep logic out of framework wiring so it can be tested without the framework.

**The pattern:**
- **At boundaries** (CLI args, config files, external APIs, network protocols): validate, return errors, handle defensively.
- **Inside the system:** typed data, error propagation, no re-validation. Trust the types.
- **Across the boundary.** Expose domain concepts, not the boundary's private representation. Keep general-purpose mechanism inside and special-purpose policy at the edge.

**Applications:**

Validation and error handling:
- Validate config at parse time (the boundary), not inside business logic
- Parse raw data into domain types at the boundary
- Do not re-export transport, storage, framework, or wire types through the public surface
- No redundant nil checks deep in call chains if the boundary already validated

Code organization:
…

Read the whole file at its exact version.

How to install

mdr add backnotprop/pstack/principle-boundary-discipline@sha256:62ac2862c2caa22d

[![mdr](https://markdownregistry.com/badge/art_kelzfi3n2ugmbx4p.svg)](https://markdownregistry.com/a/art_kelzfi3n2ugmbx4p)

Versions

The registry has recorded 3 versions of this file, between May 27, 2026 and Sep 14, 2026, about one every 55 days.

Audit of the latest version

Source

API

GET https://markdownregistry.com/api/v1/artifacts/art_kelzfi3n2ugmbx4p
GET https://markdownregistry.com/api/v1/resolve?ref=backnotprop/pstack/principle-boundary-discipline
GET https://markdownregistry.com/api/v1/blob/62ac2862c2caa22dd14531f51c9c6bb445ceb198ca98a687e25b4d47c1f10a28

Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.

Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.

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