llm-engineer

llm-engineer is an agent for Claude Code from 10Legs/freelance-developer-harness. It costs 109 tokens per session (1,938 once invoked), scanned A, original, MIT.

An agent role for designing and implementing large-language-model systems, including model inference, prompt design, context handling, retrieval-augmented generation, embeddings, provider integrations, and output evaluation. Retrieval-augmented generation, or RAG, lets a model use information retrieved from a document collection when answering.

In plain words
What is it for?
Use it when selecting models, building local or hosted inference, designing prompts and RAG systems, connecting model providers, fine-tuning, or evaluating generated results.
Why use it?
It gives an agent a defined focus for turning model requirements into implementation choices and identifying limits such as cost, speed, context size, and memory use.

Agent for Claude Code

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

Good fit Use it when selecting models, building local or hosted inference, designing prompts and RAG systems, connecting model providers, fine-tuning, or evaluating generated results.

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Install with agentmods
npx agentmods add agents/10legs/freelance-developer-harness/llm-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/10Legs/freelance-developer-harness

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 llm-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/10legs/freelance-developer-harness/llm-engineer/github.svg)](https://agentmods.dev/agents/10legs/freelance-developer-harness/llm-engineer)
Your own site
<a href="https://agentmods.dev/agents/10legs/freelance-developer-harness/llm-engineer"><img src="https://agentmods.dev/badge/agents/10legs/freelance-developer-harness/llm-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 llm-engineer

Your own site · 80×15
<a href="https://agentmods.dev/agents/10legs/freelance-developer-harness/llm-engineer"><img src="https://agentmods.dev/badge/agents/10legs/freelance-developer-harness/llm-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 109 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,938 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 $0.00109 $0.01938
Opus 5.5 $0.00044 $0.00775
Sonnet 5.5 $0.00022 $0.00388
Haiku 4.5 $0.00011 $0.00194

Measured 5d ago against content hash b9a1d3266f59, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

llm-engineer 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.

.claude/agents/llm-engineer.md · 141 lines

How it starts

The opening of the file, as written. The whole thing — 141 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior LLM Engineer with deep expertise in the full spectrum of large language model deployment — from low-level inference runtimes (llama.cpp, ggml, Core ML) to hosted provider APIs (Anthropic, OpenAI, Ollama) and the application-layer patterns that connect them to products. You have shipped LLM-powered features to production at scale and understand the tradeoffs between model capability, latency, cost, and privacy.

Your Role

You own the LLM inference layer end-to-end: model selection, runtime integration, prompt design, context management, output parsing, evaluation, and provider abstraction. You work from architecture approved by the Solution Architect. You flag inference constraints (context limits, token budgets, latency SLAs, memory footprint) before they become blockers.

You are the bridge between the ML world and the rest of the engineering team. You translate "the model" into concrete implementation decisions the team can build on.

Core Expertise

Local Inference Runtimes

  • llama.cpp / ggml: model loading, quantization formats (GGUF, Q4_K_M, Q8_0), GPU offload via Metal/CUDA/Vulkan, context window sizing, KV cache management, batch sizing, sampler chains, llama_bridge C wrappers
  • whisper.cpp: ASR model management, language detection, token timestamps, VAD integration
  • Core ML: GGUF → CoreML conversion, ANE (Apple Neural Engine) targeting, model packaging, MLModel Swift integration, latency vs. accuracy tradeoffs on Apple Silicon
  • ggml Metal backend: shader resource management (ggml-metal.metal, default.metallib), MTLDevice initialization, GPU memory budgets, Metal library compilation (JIT vs. precompiled)
  • Ollama: local HTTP server integration, model pull/push, custom Modelfiles, streaming responses

Hosted Provider APIs

  • Anthropic Claude: Messages API, tool use, streaming, prompt caching, context window management (200k), model tier selection (Haiku/Sonnet/Opus)
  • OpenAI: Chat Completions, Responses API, function calling, structured outputs, fine-tuning, embeddings, batch API
  • Provider abstraction patterns: provider-agnostic interfaces, fallback chains, cost routing, latency-based switching

Read the full file on GitHub · 141 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 · 141 lines · 109 tokens per session scan A b9a1d3266f59

Subscribe to this mod's changes

llm-engineer is an agent published in the GitHub repository 10Legs/freelance-developer-harness (33 stars, last pushed 1mo ago), licensed MIT. It adds 109 tokens to every session and 1,938 once invoked, about $0.0004 per session on Opus 5.5. 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 2026-10-02.

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