prebuild

prebuild is a skill for Claude Code, Codex from jneaimi/evaluate-before-you-build. It costs 99 tokens per session (2,437 once invoked), scanned A, original, MIT.

A pre-build checkpoint for coding tasks that asks six evaluative questions before code generation. It helps turn an idea for a feature into a confirmed build specification.

In plain words
What is it for?
Use it before building a feature, creating something, or implementing a coding task. It is focused on code generation rather than general project planning or architecture work.
Why use it?
It exposes unclear requirements and decisions before implementation begins, reducing the chance of coding against incorrect assumptions. It requires human confirmation before generating code.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: names the AskUserQuestion tool.

Good fit Use it before building a feature, creating something, or implementing a coding task. It is focused on code generation rather than general project planning or architecture work.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/jneaimi/evaluate-before-you-build/prebuild
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 jneaimi/evaluate-before-you-build --skill prebuild
Clone the repo
git clone --depth 1 https://github.com/jneaimi/evaluate-before-you-build

Made for: Claude Code, Codex.

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 prebuild

README.md
[![agentmods](https://agentmods.dev/badge/skills/jneaimi/evaluate-before-you-build/prebuild/github.svg)](https://agentmods.dev/skills/jneaimi/evaluate-before-you-build/prebuild)
Your own site
<a href="https://agentmods.dev/skills/jneaimi/evaluate-before-you-build/prebuild"><img src="https://agentmods.dev/badge/skills/jneaimi/evaluate-before-you-build/prebuild/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 prebuild

Your own site · 80×15
<a href="https://agentmods.dev/skills/jneaimi/evaluate-before-you-build/prebuild"><img src="https://agentmods.dev/badge/skills/jneaimi/evaluate-before-you-build/prebuild.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 99 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,437 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 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 5.1 $0.00099 $0.02437
Opus 5 $0.00049 $0.01218
Sonnet 5 $0.00020 $0.00487
Haiku 4.5 $0.00010 $0.00244

Measured 9d ago against content hash b4e94639dfa5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

prebuild 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 9d 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/prebuild/SKILL.md · 278 lines

How it starts

The opening of the file, as written. The whole thing — 278 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Pre-Build Checkpoint (/prebuild)

A fast, focused checkpoint that ensures you evaluate before you build. This is the discipline layer for vibe coding — 6 questions via interactive prompts, ~10 minutes, then you code with clarity instead of guessing.

Core principle: Never generate implementation code until the human has confirmed the checkpoint. Use the AskUserQuestion tool to make confirmation fast and interactive — not a wall of text.

How It Differs from /think

/prebuild /think
Focus Code generation only Any domain
Duration ~10 minutes 30-60+ minutes
Interaction AskUserQuestion with selectable options Free-form Q&A
AI role Proposes answers, human picks/adjusts Asks questions, waits
Output Build spec → code generation Full Bloom level progression
Saves to vault No (unless asked) Yes (Level 1)

Use /prebuild for features and implementation tasks. Use /think for architecture decisions, new projects, or non-code problems.


The Flow

┌──────────────────────────────────────────────────────────┐
│  1. DETECT — What is being built? (silent)               │
│  2. SCAN — Read codebase for patterns (silent)           │
│  3. ROUND 1 — AskUserQuestion: Purpose, Reuse, Risks,   │
│               Alternatives (4 interactive questions)     │
│  4. ROUND 2 — AskUserQuestion: Success Criteria,        │
│               Documentation (2 interactive questions)    │
│  5. SPEC — Compile confirmed answers (internal)          │
│  6. BUILD — Generate code from spec                      │
└──────────────────────────────────────────────────────────┘

Step 1: Detect (Silent)

Parse what the user wants to build. Identify:

  • Feature type: API endpoint, UI component, background job, integration, refactor, migration
  • Scope signal: New feature, extension, or fix?
  • Complexity signal: Single file or multi-file?

Output one line before starting the scan:

Read the full file on GitHub · 278 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. 9d ago First seen · 278 lines · 99 tokens per session scan A b4e94639dfa5

Subscribe to this mod's changes

prebuild is a skill published in the GitHub repository jneaimi/evaluate-before-you-build (2 stars, last pushed 4mo ago), licensed MIT. It adds 99 tokens to every session and 2,437 once invoked, about $0.0005 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.

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