why SKILL.md skillA
why 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/why@git:20261020.e44668cPins git:20261020.e44668c in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- backnotprop/pstack
- Path
skills/why/SKILL.md- Versions recorded
- 13
- Latest version
- git:20261020.e44668c, committed Oct 20, 2026
- First version recorded
- May 27, 2026
- Size
- 9,678 bytes
- Repository stars
- 3,337
- License
- MIT
Use for 'why does X work this way', 'why we picked Y', design rationale, regressions, postmortems, or data-backed thresholds. Discovers available MCPs and queries each evidence category (source control, issue tracker, long-form docs, real-time chat, infrastructure observability, error tracking, product analytics warehouse) in parallel, then returns a cited read on decisions and tradeoffs. Use how for runtime behavior.
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
# Why Investigate the motivation and intent behind code. The companion `how` skill answers what the code does and how it works. `why` answers what forces led to its shape. Each spawn below names a role line in the pstack settings file (`~/.cursor/rules/pstack-models.mdc` in Cursor, `~/.claude/rules/pstack-models.md` in Claude Code, `~/.agents/pstack-models.md` in other harnesses) and a default. Set `model` to that line's value, or to the default if the file or the line is missing. Leave `model` unset when the value is `auto` or `inherit-parent`. If your subagent tool rejects a slug, use the default and say so. If it rejects the default, use the closest valid slug of the same family from its error message or your harness's model list. Pick each subagent's reasoning level and fast or standard speed for the job, per the Subagents section of the **poteto-mode** skill. Every spawn is `generalPurpose` with `readonly: false` (agent mode). **Do not use readonly/Ask mode.** It strips MCP access, which disables the MCP-backed investigators and the synthesizer's citation spot-checks. Investigators still shouldn't write anything. ## Operating Posture …
Read the whole file at its exact version.
How to install
mdr add backnotprop/pstack/why@sha256:b12ea2757ff1d1d1The line at the top of this page pins the label git:20261020.e44668c, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_phmt3cyo7rqwiy27)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 13 versions of this file, between May 27, 2026 and Oct 20, 2026, about one every 12 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261020.e44668c latest | 2026-10-20 | e44668c | 9,678 B | A | view · diff |
| git:20261015.6f131f1 | 2026-10-15 | 6f131f1 | 9,627 B | A | view · diff |
| git:20261015.df856f4 | 2026-10-15 | df856f4 | 8,903 B | A | view · diff |
| git:20261012.fce11a3 | 2026-10-12 | fce11a3 | 9,494 B | A | view · diff |
| git:20261012.f3afb70 | 2026-10-12 | f3afb70 | 8,770 B | A | view · diff |
| git:20261008.1edf0a5 | 2026-10-08 | 1edf0a5 | 11,086 B | A | view · diff |
| git:20261008.4aed5af | 2026-10-08 | 4aed5af | 10,362 B | A | view · diff |
| git:20261004.124f622 | 2026-10-04 | 124f622 | 11,084 B | A | view · diff |
| git:20261004.c0c3f13 | 2026-10-04 | c0c3f13 | 10,360 B | A | view · diff |
| git:20260914.aa2db46 | 2026-09-14 | aa2db46 | 10,809 B | A | view · diff |
| git:20260914.55bfdc2 | 2026-09-14 | 55bfdc2 | 9,999 B | A | view · diff |
| git:20260819.4b32d9d | 2026-08-19 | 4b32d9d | 21,343 B | A | view · diff |
| git:20260527.b3eabf1 | 2026-05-27 | b3eabf1 | 23,181 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (9678 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
backnotprop/pstack · 3,337 stars · license MIT · pushed 2026-10-28 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_phmt3cyo7rqwiy27 GET https://markdownregistry.com/api/v1/resolve?ref=backnotprop/pstack/why GET https://markdownregistry.com/api/v1/blob/b12ea2757ff1d1d111c7b4e74e3e764d337c6a08458b8d6240d3f01c4be490ec
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.
More from backnotprop/pstack
Every file in backnotprop/pstack