An interview-driven tool for writing detailed prompts for coding or agent tasks, aimed at Claude Opus 4.7 or GPT-5.5 Codex CLI. It can also produce an optional SPEC.md handoff file.

Use it to scope coding tasks, design agent instructions, write implementation prompts, and prepare a specification for another coding session.

A vague coding request can leave important decisions unstated and make another agent work from guesswork. The tool asks structured questions before producing a precise prompt.

forge — Skill for Claude Code and Codex by yz5e/agent-skills

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 yz5e/agent-skills --skill forge

Clone the repo

git clone --depth 1 https://github.com/yz5e/agent-skills

Made for: Claude Code, Codex.

Its marketplace also offers this one on its own, as the plugin forge — /plugin install forge after adding the marketplace above.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/yz5e/agent-skills/forge/github.svg)](https://agentmods.dev/skills/yz5e/agent-skills/forge)

Your own site

<a href="https://agentmods.dev/skills/yz5e/agent-skills/forge"><img src="https://agentmods.dev/badge/skills/yz5e/agent-skills/forge/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/yz5e/agent-skills/forge"><img src="https://agentmods.dev/badge/skills/yz5e/agent-skills/forge.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 5,354 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.

Model	Per session	Once invoked
Fable 5.1	$0.00000	$0.05354
Opus 5.5	$0.00000	$0.02142
Sonnet 5.5	$0.00000	$0.01071
Haiku 4.5	$0.00000	$0.00535

Measured 2mo ago against content hash 336012bd1bc9, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

forge 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 2mo 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/forge/SKILL.md · 406 lines

How it starts

The opening of the file, as written. The whole thing — 406 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/forge

Interview the user with structured multiple-choice questions, then forge a prompt that another agent session can execute with minimal ambiguity. Targets Claude Opus 4.7 or GPT-5.5 (Codex CLI). Use this skill for coding and agentic prompt design, anywhere from a single bug-fix prompt to a long-horizon repo migration.

The skill has three phases: interview, draft, deliver.

Read references/anthropic-claude-prompting.md when targeting Opus 4.7 and the task is long-horizon, tool-heavy, or expensive enough that prompt quality materially matters. Read references/openai-gpt-5-5-prompting.md when targeting GPT-5.5 or Codex.

Activation

Two ways to invoke:

Bare: /forge. Open with "What do you need a prompt for?" and treat the user's reply as the seed.
Seeded: /forge <topic>. Use the topic as the interview seed, skip the opening question, and dive into clarifications.

The skill also activates conversationally when the user says things like "help me write a prompt", "I need an Opus 4.7 prompt", "scope this for me", or asks for prompt design. When activated conversationally, treat the user's most recent message as the seed.

Run /forge in the main session, never in a forked subagent. Subagents cannot relay user replies in either Claude Code or Codex, so the interview will hang.

Phase 1: Interview

Run an adaptive interview. Pick the transport based on the harness, then start with up to 5 base questions. Add deeper questions only when answers flag complexity (long-horizon, tool-heavy, subagent-orchestrated, validation-heavy, multi-system).

Interview transport

The skill ships in two harnesses with different interaction primitives. Detect which is available and pick the matching transport. Never invent a tool that is not in your toolset.

Claude Code (any mode, including outside plan mode): use the AskUserQuestion tool. Up to 4 questions per call, 2 to 4 options each, header max 12 chars. An "Other" free-text choice is available by setting the per-question option that displays an additional free-text choice after the listed options.
Codex CLI / Codex app, and any harness without AskUserQuestion: use the text fallback below. Codex does not expose a multi-choice modal to skills or custom prompts. The selection modals you see in the Codex Mac app are wired to built-in slash commands (/plan, /model, /agent etc.), not to user code, so the skill cannot trigger them. It renders questions as plain text and waits for the user's reply.

Read the full file on GitHub · 406 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

2mo ago First seen · 406 lines · 0 tokens per session scan A 336012bd1bc9

Subscribe to this mod's changes

forge is a skill published in the GitHub repository yz5e/agent-skills (17 stars, last pushed 6mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 5,354 tokens. 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.

Building agents Data and AI Prompting

forge next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
forgeyz5e/agent-skills	Skill	17	6mo ago	MIT	A	0	Claude Code, Codex
llm-app-patternsdavila7/claude-code-templates	Skill	33k	yesterday	MIT	A	54	Claude Code, Codex
prompt-engineerJeffallan/claude-skills	Skill	12k	7d ago	MIT	A	93	Claude Code
prompt-optimizationlangwatch/langwatch	Skill	5.0k	yesterday	Apache-2.0	A	105	Claude Code, Codex
omh-model-optimizationrlaope/oh-my-hermes	Skill	5.2k	yesterday	MIT	A	84	Claude Code, Codex
ideogram4digitalsamba/claude-code-video-toolkit	Skill	2.5k	yesterday	MIT	A	99	Claude Code
prompt-library-for-startupsaws/agent-toolkit-for-aws	Skill	3.4k	yesterday	Apache-2.0	A	228	Claude Code