why

Investigate design rationale behind code by querying seven evidence sources in parallel.

Updated Sep 2, 2026
One-click install
npx skills add https://github.com/jnyross/pstack-muse --skill why-jnyross
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: why
Source: https://github.com/jnyross/pstack-muse/tree/main/skills/why
Command: npx skills add https://github.com/jnyross/pstack-muse --skill why-jnyross

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve? Code tells you what it does but rarely why it exists. This Skill reconstructs the historical motivation behind code—design decisions, tradeoffs, rejected alternatives, and business constraints—by searching fragmented evidence across source control, tickets, docs, chat, observability, error tracking, and analytics systems. ## Core Features & Use Cases - Parallel Multi-Source Investigation: Discovers available MCPs, maps them to seven evidence categories, and spawns one investigator subagent per category to search concurrently. - Confidence-Calibrated Synthesis: A synthesizer subagent merges findings into a cited narrative that strictly separates direct evidence, inference, competing hypotheses, and explicit gaps. - Epistemic Discipline: Enforces a five-tier confidence framework with hedged phrasing rules, contradiction surfacing, and null-result reporting so thin evidence never becomes confident storytelling. - Use Case: Ask why a retry limit is set to 3 in a payment module; the Skill traces the PR, linked Linear ticket, Slack incident thread, Datadog monitor, and Sentry issue to show the threshold came from a specific outage postmortem. ## Quick Start Ask the AI to use the why skill to investigate why a specific function or threshold in your codebase was designed the way it was.

Frequently Asked Questions about why

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I find out why code was written a certain way?

Anchor the investigation with git blame and git log on the target lines, then search PR discussions, tickets, docs, chat threads, and telemetry in parallel. This Skill automates that workflow and returns a cited, confidence-calibrated answer.

What is the difference between the why and how skills?

The how skill explains what code does and how it works at runtime. The why skill explains the forces that shaped it: design rationale, business constraints, rejected alternatives, and incident history.

Which MCP servers does the why skill need?

Only git and gh are guaranteed; the other six categories (Linear, Notion, Slack, Datadog, Sentry, Databricks or equivalents) are discovered at runtime. Missing MCPs are reported as explicit coverage gaps rather than silently skipped.

Can the why skill work without access to Slack or Notion?

Yes, it proceeds with whatever sources are available and documents unsearched categories in the Sources Consulted section. Null results and unavailable sources are treated as first-class evidence about how the decision was recorded.

Why does the why skill avoid confident answers?

Historical evidence is fragmentary and sometimes contradictory, so every claim is tiered as Direct, Supported, Inferred, Speculative, or Unknown. Hedged phrasing is enforced so users can distinguish cited facts from interpretation.