forge-modular

forge-modular is a skill for Claude Code, Codex from Generous-Corp/pulp. It costs 28 tokens per session (29,034 once invoked), scanned A, original, MIT.

A guide to generating and checking VCV Rack modules and patches, including code built inside a Forge worktree. VCV Rack is software for assembling virtual modular-synthesizer components.

In plain words
What is it for?
Use it when generating modules or patches, interpreting generator results, handling partial results, and checking the boundary between the main project and its Forge worktree.
Why use it?
It warns that a passing check may not prove the intended work happened and explains how to preserve useful output when generation falls short.

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/generous-corp/pulp/forge-modular
Any agent
npx skills add Generous-Corp/pulp --skill forge-modular
Clone the repo
git clone --depth 1 https://github.com/Generous-Corp/pulp

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 forge-modular

README.md
[![agentmods](https://agentmods.dev/badge/skills/generous-corp/pulp/forge-modular.svg)](https://agentmods.dev/skills/generous-corp/pulp/forge-modular)
Your own site
<a href="https://agentmods.dev/skills/generous-corp/pulp/forge-modular"><img src="https://agentmods.dev/badge/skills/generous-corp/pulp/forge-modular.svg" alt="Measured on agentmods" height="20"></a>
Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 29,034 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 $0.00028 $0.29034
Opus 5 $0.00014 $0.14517
Sonnet 5 $0.00006 $0.05807
Haiku 4.5 $0.00003 $0.02903

Measured today against content hash 9967ad08e059, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

forge-modular 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.

.agents/skills/forge-modular/SKILL.md · 2,123 lines

How it starts

The opening of the file, as written. The whole thing — 2,123 lines — stays where its author put it; the contents beside it link to each section on GitHub.

forge-modular — generating VCV Rack modules and patches, and proving it

Covers tools/rack/ (the generator, the patch idiom library, the gates), examples/forge-modular/ (the module pack), and forge-seam/ (the app's sources, which live here and are built inside a Forge worktree).

Read this before trusting any green result in this area. Everything below cost a session at least once, and most of it was a test or a tool reporting success for work it had not done.

A run that fails still has to hand something over

generate() returns (patch, why, shortfall). shortfall is None on a pass and a Shortfall when the loop ran out of attempts and is handing over the best thing it built. It only raises SystemExit when there is genuinely nothing to hand over — no attempt ever got past the lint.

The rule this encodes: an advisory verdict is not fatal, and out of attempts is not the same as nothing to show. The loop used to raise SystemExit("gave up after 5 attempts") after generating five patches its own transcript had called "structurally sound" and "keeping the patch anyway", and the user got nothing — not the patches, not a copyable reason. "Not a sequenced-voice patch yet" is a wording that means the loop should keep going, not that the patch is worthless.

Consequences to keep in step when touching this:

  • The build writes the handover as <slug>-unfinished.vcv, prints the "built N modules, M cables → path" line the app parses for an artifact, then the handover_report() block, and exits 1. Dropping either the exit code or the gave up after phrase breaks a different reader: the shell decides a run ended by classifying that phrase, so without it the app watches a dead build forever.
  • A patch that failed the lint never becomes a Shortfall. It names modules Rack cannot create, so handing it over offers a file that will not open.
  • Shortfall.rank is (severity, misses, -attempt), lowest wins: a patch that plays beats one measured silent, fewer missed requirements beats more, and only a tie goes to the later attempt. Rank on requirements missed, never on the number of LINES it takes to say so — naming installed jacks adds lines, and ranking on those would rate a patch worse for every jack we managed to name.
  • keep_attempt is not gated on FORGE_ATTEMPT_DIR any more. It was, and nothing but prove_idioms.sh ever set it, so every app build kept nothing while the log claimed otherwise. The default is a stamped per-pid directory under ~/Library/Application Support/Forge Modular/attempts/.

Read the full file on GitHub · 2,123 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 · 2,123 lines · 28 tokens per session scan A 9967ad08e059

Subscribe to this mod's changes

forge-modular is a skill published in the GitHub repository Generous-Corp/pulp (16 stars, last pushed today), licensed MIT. It adds 28 tokens to every session and 29,034 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 2026-09-04.

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