memstack-development-mentor

A teaching mode for coding work that explains decisions, trade-offs, and reasoning in plain language while a task is being completed.

In plain words
What is it for?
Use it when learning a codebase, understanding why an approach was chosen, or following along while building a feature.
Why use it?
It helps someone learn from the implementation instead of receiving only the finished code or result.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/cwinvestments/memstack/mentor
Any agent
npx skills add cwinvestments/memstack --skill mentor
Clone the repo
git clone --depth 1 https://github.com/cwinvestments/memstack

Made for: Claude Code, Codex.

Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,400 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00069 $0.01400
Opus 5 $0.00034 $0.00700
Sonnet 5 $0.00014 $0.00280
Haiku 4.5 $0.00007 $0.00140

Measured 2d ago against content hash 247114834e45, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

memstack-development-mentor 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 2d 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/development/mentor/SKILL.md · 166 lines

How it starts

The opening of the file, as written. The whole thing — 166 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Mentor — Activating mentor mode...

Narrates decisions, tradeoffs, and reasoning in plain language as you build, so the user learns by working alongside you.

Activation

Trigger Status
User says "teach me" or "mentor mode" ACTIVE
User says "explain as you go" or "walk me through" ACTIVE
User says "help me learn" or "learning mode" ACTIVE
User wants a code review after the fact NOT this skill — use Code Reviewer
User wants debugging help NOT this skill — debug directly

Context Guard

  • Do NOT use for post-hoc code review (that's code-reviewer)
  • Do NOT use for debugging existing bugs (debug directly)
  • Do NOT use for documentation writing
  • This skill changes HOW you work — narrating as you go — not WHAT you build

How Mentor Mode Works

Mentor mode is a behavioral overlay, not a standalone task. When active, it modifies how you approach ANY other task. You still build what the user asked for, but you narrate your thinking at each decision point.

The rule: Before every non-trivial action, explain WHY in 1-3 sentences. After every non-trivial action, explain WHAT just happened and what you'd consider differently.

Narration Framework

Before each decision, state:

Why I'm choosing this approach:
[1-2 sentences explaining the reasoning]

What I considered and rejected:
[1-2 alternatives and why they're worse here]

After each action, state:

What just happened:
[1 sentence summarizing the change]

What to watch for:
[1 sentence about potential issues or next considerations]

Narration density

Adjust based on the user's apparent experience level:

Signal Level Narration Style
User asks "what is a..." questions Beginner Explain concepts, define terms, narrate every step
User asks "why this over..." questions Intermediate Focus on tradeoffs and alternatives, skip basics
User asks "teach me the advanced..." Advanced Focus on edge cases, performance, architecture patterns

Read the full file on GitHub · 166 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. 2d ago First seen · 166 lines · 69 tokens per session scan A 247114834e45

Subscribe to this mod's changes

memstack-development-mentor is a skill published in the GitHub repository cwinvestments/memstack (417 stars, last pushed 5d ago), licensed MIT. It adds 69 tokens to every session and 1,400 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 2026-08-30.

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