build-prompt

build-prompt is a skill for Claude Code from rp1-run/rp1. It costs 23 tokens per session (2,077 once invoked), scanned A, original, Apache-2.0.

A six-stage workflow for creating or improving a prompt or agent skill, with a separate report about the result.

In plain words
What is it for?
It is for producing prompt or skill files, applying an improvement overlay to an existing file, and generating a confidence report.
Why use it?
Building agent instructions by hand can miss requirements or lack a consistent review process. This workflow applies the same governed process each time and leaves the original file unchanged when improving it.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Part of the rp1-utils plugin — 4 skills, 1 agent shipped together

Good fit It is for producing prompt or skill files, applying an improvement overlay to an existing file, and generating a confidence report.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/rp1-run/rp1/build-prompt
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 rp1-run/rp1 --skill build-prompt
Clone the repo
git clone --depth 1 https://github.com/rp1-run/rp1

Made for: Claude Code.

Or install rp1-utils, the plugin that ships this one along with the rest of its 4 skills, 1 agent.

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 build-prompt

README.md
[![agentmods](https://agentmods.dev/badge/skills/rp1-run/rp1/build-prompt/github.svg)](https://agentmods.dev/skills/rp1-run/rp1/build-prompt)
Your own site
<a href="https://agentmods.dev/skills/rp1-run/rp1/build-prompt"><img src="https://agentmods.dev/badge/skills/rp1-run/rp1/build-prompt/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 build-prompt

Your own site · 80×15
<a href="https://agentmods.dev/skills/rp1-run/rp1/build-prompt"><img src="https://agentmods.dev/badge/skills/rp1-run/rp1/build-prompt.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,077 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 $0.00023 $0.02077
Opus 5 $0.00012 $0.01038
Sonnet 5 $0.00005 $0.00415
Haiku 4.5 $0.00002 $0.00208

Measured 5d ago against content hash 6967bd1bea28, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

build-prompt 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 5d 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.

plugins/utils/skills/build-prompt/SKILL.md · 252 lines

How it starts

The opening of the file, as written. The whole thing — 252 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Build Prompt

YOU ARE A PURE ORCHESTRATOR. Spawn the pipeline-runner agent for all prompt creation work. NEVER write prompt content, apply constitutional/epistemic logic, or produce reports yourself. Your only job: spawn agent, parse response, write artifacts, emit events.

§CTX

Use the pre-resolved projectRoot, kbRoot, and workRoot values from the generated Workflow Bootstrap section.

Output directory:

OUT_DIR = {workRoot}/prompts/{YYYY-MM-DD}-{PROMPT_NAME}/
Variable Source
{YYYY-MM-DD} Current date, ISO 8601
{PROMPT_NAME} Kebab-case slug from argument

Output file naming:

TYPE Primary artifact Report
prompt {PROMPT_NAME}.md confidence-report.md
skill SKILL.md confidence-report.md

EXISTING prompt handling: When EXISTING is provided, the path is passed through to the pipeline runner, which loads the file at Stage 0. The original file is never modified. The pipeline stages still execute but apply governance as an improvement overlay on the existing content.

STATE-MACHINE

stateDiagram-v2
    [*] --> pipeline_start
    pipeline_start --> pipeline_complete : agent_done
    pipeline_complete --> [*] : done

On each phase transition, report via:

rp1 agent-tools emit \
  --workflow build-prompt \
  --type status_change \
  --run-id {RUN_ID} \
  --name "{RUN_NAME}" \
  --step {CURRENT_STATE} \
  --data '{"status": "running"}'
  • RUN_ID comes from the generated Workflow Bootstrap section
  • Derive RUN_NAME from PROMPT_NAME: "Prompt: {PROMPT_NAME}"

State Progression Protocol:

  1. Report each --step with --data '{"status": "running"}' when you enter that state
  2. For non-terminal states: move to the NEXT state when done
  3. For terminal states (those with -> [*] transitions): report with --data '{"status": "completed"}' and --close-run

§STEP-1: Pipeline Execution

Emit entry into pipeline_start:

Read the full file on GitHub · 252 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. 5d ago First seen · 252 lines · 23 tokens per session scan A 6967bd1bea28

Subscribe to this mod's changes

build-prompt is a skill published in the GitHub repository rp1-run/rp1 (38 stars, last pushed 5d ago), licensed Apache-2.0. It adds 23 tokens to every session and 2,077 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 2026-09-07.

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