pstack-why

pstack-why is a skill for Claude Code from dmae97/omk. It costs 92 tokens per session (2,177 once invoked), scanned A, original, MIT.

A research workflow for finding why code or product decisions were made. It can consult sources such as version control, issue trackers, documents, chat, monitoring, error tracking, and product analytics through available MCP connections.

In plain words
What is it for?
It helps answer questions about design choices, historical changes, incidents, and thresholds by collecting evidence from project records.
Why use it?
Code often shows what a system does but not the reasons behind it. This workflow helps investigate intent, regressions, postmortems, and data-backed limits.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: reads .claude/ paths; mentions subagents; mentions Claude Code.

Good fit It helps answer questions about design choices, historical changes, incidents, and thresholds by collecting evidence from project records.

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Install with agentmods
npx agentmods add skills/dmae97/omk/why
View source ↗ dmae97/omk
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 dmae97/omk --skill why
Clone the repo
git clone --depth 1 https://github.com/dmae97/omk

Made for: Claude Code.

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 pstack-why

README.md
[![agentmods](https://agentmods.dev/badge/skills/dmae97/omk/why/github.svg)](https://agentmods.dev/skills/dmae97/omk/why)
Your own site
<a href="https://agentmods.dev/skills/dmae97/omk/why"><img src="https://agentmods.dev/badge/skills/dmae97/omk/why/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for pstack-why

Your own site · 80×15
<a href="https://agentmods.dev/skills/dmae97/omk/why"><img src="https://agentmods.dev/badge/skills/dmae97/omk/why.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 92 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,177 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 unknown 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 $0.00092 $0.02177
Opus 5.5 $0.00037 $0.00871
Sonnet 5.5 $0.00018 $0.00435
Haiku 4.5 $0.00009 $0.00218

Measured today against content hash c9520f5237c9, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

pstack-why 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 today.

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.

packages/coding-agent/resources/pstack/skills/why/SKILL.md · 101 lines

How it starts

The opening of the file, as written. The whole thing — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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

Operate as a careful, cautious, and precise investigator. Be honest about what you know vs what you're inferring. Read references/epistemics.md for the full confidence framework and phrasing guide. The synthesizer must follow it.

Step 1. Understand the Target and the Question

The target is usually a chunk of code, a pattern, a feature, or a named design decision. The question is usually a design rationale, a tradeoff, a motivating edge case, an external constraint, dead code, or a broad history sweep.

If the target is vague ("why do we do it this way?" with no clear referent), make your best guess from conversation context (open files, recent edits, cursor location, what was just discussed). State your interpretation briefly so the user can redirect if you're off, then proceed.

Step 2. Establish the Code Anchor

Read the full file on GitHub · 101 lines

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. today First seen · 101 lines · 92 tokens per session scan A c9520f5237c9

Subscribe to this mod's changes

pstack-why is a skill published in the GitHub repository dmae97/omk (149 stars, last pushed today), licensed MIT. It adds 92 tokens to every session and 2,177 once invoked, about $0.0004 per session on Opus 5.5. 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 2026-10-27.