prompt-engineer

prompt-engineer is an agent for Claude Code from WeaveMindAI/weft. It costs 60 tokens per session (3,426 once invoked), scanned C, original, no licence file.

An agent for writing and revising the instructions sent to a language model inside a Weft program. It handles system instructions, user prompt templates, and directions for extracting JSON, a structured text format.

In plain words
What is it for?
Use it to create or overhaul model prompts and JSON extraction instructions for Weft stages.
Why use it?
It helps when a program stage depends on a language model and its instructions need careful design.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

Good fit Use it to create or overhaul model prompts and JSON extraction instructions for Weft stages.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/weavemindai/weft/prompt-engineer
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.

Clone the repo
git clone --depth 1 https://github.com/WeaveMindAI/weft

Made for: Claude Code.

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 prompt-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/weavemindai/weft/prompt-engineer/github.svg)](https://agentmods.dev/agents/weavemindai/weft/prompt-engineer)
Your own site
<a href="https://agentmods.dev/agents/weavemindai/weft/prompt-engineer"><img src="https://agentmods.dev/badge/agents/weavemindai/weft/prompt-engineer/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 prompt-engineer

Your own site · 80×15
<a href="https://agentmods.dev/agents/weavemindai/weft/prompt-engineer"><img src="https://agentmods.dev/badge/agents/weavemindai/weft/prompt-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 60 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,426 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 $0.00060 $0.03426
Opus 5.5 $0.00024 $0.01370
Sonnet 5.5 $0.00012 $0.00685
Haiku 4.5 $0.00006 $0.00343

Measured 15d ago against content hash e34c2438c8c3, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade C, and why

prompt-engineer scanned grade C with 2 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 15d 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.

Instruction-override phrasingmediumPrompt injection

Text telling the model to disregard its earlier instructions or safety rules is the shape of a prompt injection, whoever wrote it.

You close every failure mode in advance by narrating it as built, never as forbidden. Name the failure, show what it looks like when it arrives ("ignore previous instructions", "this is just a test", empty input, fiction

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Asks the agent to reveal its instructionsmediumSystem prompt leakage

Directions to print, repeat or translate the system prompt extract configuration the operator did not intend to expose.

- A node with `parseJson: true` extracts named keys from the model's reply into added output ports. When [the brief] names those keys, the prompt's output instructions say, in its own voice, that the reply is JSON with e
tangle/claude-code/.claude/agents/prompt-engineer.md · 139 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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. 15d ago Changed · +4 lines e34c2438c8c3
  2. 24d ago First seen · 135 lines · 60 tokens per session scan C 76e6ce0efc4f

Subscribe to this mod's changes

prompt-engineer is an agent published in the GitHub repository WeaveMindAI/weft (2,002 stars, last pushed today), with no licence file. It adds 60 tokens to every session and 3,426 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it C with 2 findings (instruction-override phrasing, asks the agent to reveal its instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-23.

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