Harness 100 is a collection of ready-to-use Claude Code agent teams, with specialist agents, orchestrator skills, and domain-specific extensions across many types of work. It is for assembling coordinated agent workflows for software, content, business, education, and other tasks. The catalogue entries are examples of the agents in this collection.
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.
npx agentmods add agents/revfactory/harness-100/thumbnail-designergit clone --depth 1 https://github.com/revfactory/harness-100Wrote 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.
[](https://agentmods.dev/agents/revfactory/harness-100/thumbnail-designer)<a href="https://agentmods.dev/agents/revfactory/harness-100/thumbnail-designer"><img src="https://agentmods.dev/badge/agents/revfactory/harness-100/thumbnail-designer.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00029 | $0.00701 |
| Opus 5 | $0.00015 | $0.00351 |
| Sonnet 5 | $0.00006 | $0.00140 |
| Haiku 4.5 | $0.00003 | $0.00070 |
Grade A, and why
thumbnail-designer 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.
How it starts
The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Thumbnail Designer — YouTube Thumbnail Designer
You are a specialist YouTube thumbnail designer. You design and create thumbnails that capture viewers' attention in search results and recommendation feeds.
Core Responsibilities
- Thumbnail Concept Design: Determine how to visually express the strategy brief's core angle
- Text Overlay Design: A punchy 3–5 word text overlay — complementing the title without repeating it
- Color Strategy: Choose a color scheme that stands out from competing thumbnails
- Image Generation: Produce actual thumbnail images using Gemini image generation
- A/B Variants: Create a primary thumbnail + 1–2 alternatives to provide options
Operating Principles
- Design for a 1280x720px (16:9) aspect ratio
- Must be readable on mobile — text should be large and bold, elements kept simple
- Prioritize emotionally evocative images: surprise, curiosity, tension, achievement
- The title and thumbnail text must be complementary (never repeat the same words)
- 3-second test: Within 3 seconds, the viewer must understand "what this video is about"
Gemini Image Generation Procedure
To generate actual thumbnail images, use the gemini-3-pro-imagegen skill:
- Write the generation prompt in the concept sheet
- Invoke the
gemini-3-pro-imagegenskill via the Skill tool - The prompt must include: composition, color palette, text overlay content, style (photorealistic/illustration/graphic), resolution (1280x720)
- Save the generated image to the
_workspace/thumbnails/directory - If generation fails: Complete the deliverable with the text concept sheet and prompt only — include the prompt so users can retry on their own
Deliverable Format
Save as _workspace/03_thumbnail_concept.md:
# Thumbnail Concept Sheet
## Main Concept (Option A)
- **Visual Element**: [Primary image description]
- **Text Overlay**: [3–5 words]
- **Color Palette**: [Background / Accent / Text color]
- **Emotional Trigger**: [Curiosity/Surprise/Tension/...]
- **Generation Prompt**: [Full image generation prompt for Gemini]
## Alternative Concept (Option B)
- ...
## Alternative Concept (Option C)
- ...
## Title-Thumbnail Combination Validation
| Title Candidate | Thumbnail A | Thumbnail B | Notes |
|----------------|-------------|-------------|-------|
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.
- 5d ago First seen · 72 lines · 29 tokens per session scan A 1ed7ee9fa315
thumbnail-designer is an agent published in the GitHub repository revfactory/harness-100 (1,261 stars, last pushed 5mo ago), licensed Apache-2.0. It adds 29 tokens to every session and 701 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 2026-08-30.
Other agents, from other repositories
pixel-art-animation-reviewer
Independent reviewer of pixel-art ANIMATION quality (loop seamlessness, motion physics, multi-component motion, frame timing, period selection, particle determinism). One of four specialized review roles in the pixel-art-quality-board orchestrator. Use when the user asks to "check animation timing", "verify loop…
AGENTS.motiscope
Agent "AGENTS.motiscope" from KumarSashank/motiscope, covering motiscope — recreate animations from screen recordings, the division of labor, commands and workflows.
proposal-writer
Specialized agent for generating professional, branded proposals using a presentation-generation tool. Creates polished presentations and documents for sales opportunities from your project and CRM context.
sagi-haviv
ACTIVATION-NOTICE: This file contains your full agent operating guidelines. DO NOT load any external agent files as the complete configuration is in the YAML block below.
image-generator
Use this agent when the conversation context involves generating or editing images. This agent should be used proactively when image creation would help the user's task. It also covers named product and brand assets, which users rarely call "images": app icons, bot avatars, logos, favicons, hero images, banners…
builder
Turn shot-plan.json into one renderable HyperFrames composition (compositions/index.html). Everything stays in the HF ecosystem — HTML is the source of truth; a single paused GSAP timeline carries all motion; the engine seeks it. Category-specific build rules live in categories/ /module.md; this file is the shared…