lean-crew-builder

lean-crew-builder is an agent for coding agents from utk2103/Prompt-Studio. It costs 75 tokens per session (387 once invoked), scanned A, a copy of cavecrew-builder, Apache-2.0.

A narrowly scoped editing agent for making small changes in one or two existing files. It handles tasks such as typo fixes, single-function rewrites, mechanical renames, and formatting-preserving edits.

In plain words
What is it for?
Use it for bounded corrections when the target files and changes are already clear.
Why use it?
It keeps simple edits limited in scope and provides a concise record of exactly what changed. It refuses work that would require a larger refactor or new feature.

Agent

Part of the prompt-studio plugin — 9 skills, 3 agents 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 agents/utk2103/prompt-studio/lean-crew-builder
Clone the repo
git clone --depth 1 https://github.com/utk2103/Prompt-Studio

Or install prompt-studio, the plugin that ships this one along with the rest of its 9 skills, 3 agents.

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 lean-crew-builder

README.md
[![agentmods](https://agentmods.dev/badge/agents/utk2103/prompt-studio/lean-crew-builder.svg)](https://agentmods.dev/agents/utk2103/prompt-studio/lean-crew-builder)
Your own site
<a href="https://agentmods.dev/agents/utk2103/prompt-studio/lean-crew-builder"><img src="https://agentmods.dev/badge/agents/utk2103/prompt-studio/lean-crew-builder.svg" alt="Measured on agentmods" height="20"></a>
Per session 75 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 387 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 91% copy Near-identical to another mod 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 $0.00075 $0.00387
Opus 5 $0.00037 $0.00193
Sonnet 5 $0.00015 $0.00077
Haiku 4.5 $0.00007 $0.00039

Measured 4d ago against content hash 87ea771e9ae3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

lean-crew-builder 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 4d 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.

Origin

This is a copy

91% identical to cavecrew-builder — 8 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

agents/lean-crew-builder.md · 48 lines

What it actually says

Lean-ultra prose. Drop articles/filler. Code/paths exact, backticked. No narration.

Scope

1 file ideal. 2 OK. 3+ → refuse. Edit existing only (new file iff user asked). No new abstractions. No drive-by refactors. No comment additions. No Bash available — cannot shell out, cannot push, cannot delete.

Workflow

  1. Read target(s). Never edit blind.
  2. Edit smallest diff that work.
  3. Re-Read to verify.
  4. Return receipt.

Output (receipt)

<path:line-range> — <change ≤10 words>.
<path:line-range> — <change ≤10 words>.
verified: <re-read OK | mismatch @ path:line>.

Diff is the artifact. Receipt is the proof. No exploration story.

Refusals (terminal lines)

3+ files → too-big. split: <n one-line tasks>. Destructive needed → needs-confirm. op: <command>. Spec ambiguous → ambiguous. ask: <one question>. Tests fail post-edit, can't fix in scope → regressed. revert path:line. cause: <fragment>.

Auto-clarity

Security or destructive paths → write normal English warning, then resume Lean-ultra.

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. 4d ago First seen · 48 lines · 75 tokens per session scan A 87ea771e9ae3

Subscribe to this mod's changes

lean-crew-builder is an agent published in the GitHub repository utk2103/Prompt-Studio (7 stars, last pushed 4d ago), licensed Apache-2.0. It adds 75 tokens to every session and 387 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 91% identical to cavecrew-builder, differing in 8 lines, and is treated as a copy.