matcha:why

matcha:why is a command for Codex from plumpslabs/matcha. It costs 20 tokens per session (692 once invoked), scanned A, original, MIT.

A planning command that clarifies the problem, goals, success criteria, and the What, Why, and How before code is changed.

In plain words
What is it for?
It is for defining the scope, expected outcome, evidence, assumptions, unknowns, and simplest implementation plan for a software task.
Why use it?
It reduces the risk of solving the wrong problem or starting work without enough evidence to know what success means.

Command for Codex

Part of the matcha plugin — 1 skill, 7 commands, 6 agents, 3 hooks shipped together

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 commands/plumpslabs/matcha/matcha-why
Clone the repo
git clone --depth 1 https://github.com/plumpslabs/matcha

Made for: Codex.

Or install matcha, the plugin that ships this one along with the rest of its 1 skill, 7 commands, 6 agents, 3 hooks.

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 matcha:why

README.md
[![agentmods](https://agentmods.dev/badge/commands/plumpslabs/matcha/matcha-why.svg)](https://agentmods.dev/commands/plumpslabs/matcha/matcha-why)
Your own site
<a href="https://agentmods.dev/commands/plumpslabs/matcha/matcha-why"><img src="https://agentmods.dev/badge/commands/plumpslabs/matcha/matcha-why.svg" alt="Measured on agentmods" height="20"></a>
Per session 20 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 692 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 $0.00020 $0.00692
Opus 5 $0.00010 $0.00346
Sonnet 5 $0.00004 $0.00138
Haiku 4.5 $0.00002 $0.00069

Measured 3d ago against content hash 6ce595c232f0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

matcha: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 3d 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.

.agents/commands/matcha:why.md · 63 lines

How it starts

The opening of the file, as written. The whole thing — 63 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/matcha:why

Intent Discovery. Before planning or touching code, discover the intent: what problem is being solved, what success looks like, and the What → Why → How with evidence. Can't answer Why or How? → STOP unless trivial (≤5 LOC, 1 file, no logic change) — for trivia, proceed on a stated assumption and flag it. Never stop the user for a typo.

Process

Field What to answer Minimum evidence
Problem Exact problem or request being addressed Specific error, user request, or requirement
Goals What success looks like Desired outcome, acceptance behavior
Success Criteria How we know it's done Measurable, testable condition
What Scope of the change Specific files/areas affected
Why What breaks without this Impact, user pain, business cost
How Simplest full solution Step-by-step, file-by-file plan
Assumptions What we take as given Constraints, existing patterns
Unknowns What still needs discovery Open questions → resolve in context/reuse stages

What/Why/How is one technique inside Intent Discovery — the container also captures problem, goals, success criteria, assumptions, and unknowns.

Decision Matrix

Confidence Action
HIGH on Problem/Why/How ✅ Proceed to planning
MEDIUM on Why or How ⚠️ Ask user to clarify (skip for trivial tasks — proceed on assumption)
LOW on any 🛑 STOP for nontrivial. For trivial (≤5 LOC, 1 file): proceed on a recorded assumption and flag it. Don't block a typo on missing "Why evidence".

Report Format

🍵 matcha: Intent Discovery

Task: [what was requested]

Problem:       [exact problem]
Goals:         [desired outcome]
Success:       [measurable done condition]
What:          [scope — be specific]
Why:           [impact without this — with evidence]
How:           [simplest solution — numbered steps]
Assumptions:   [what's taken as given]
Unknowns:      [what needs discovery]

Confidence: HIGH / MEDIUM / LOW

[If MEDIUM/LOW: what's unclear → ask user]

Read the full file on GitHub · 63 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. 3d ago First seen · 63 lines · 20 tokens per session scan A 6ce595c232f0

Subscribe to this mod's changes

matcha:why is a command published in the GitHub repository plumpslabs/matcha (1 stars, last pushed 23d ago), licensed MIT. It adds 20 tokens to every session and 692 once invoked, about $0.0001 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 2026-08-31.