PenguinHarness is a local-first platform in which multiple AI agents create, evaluate, optimize, and deploy agent applications. It is for people building AI software who want agents to generate applications and improve their own behavior through skills.
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 skills add Prism-Shadow/penguin-harness --skill software-engineeringgit clone --depth 1 https://github.com/Prism-Shadow/penguin-harnessWrote 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/skills/prism-shadow/penguin-harness/software-engineering)<a href="https://agentmods.dev/skills/prism-shadow/penguin-harness/software-engineering"><img src="https://agentmods.dev/badge/skills/prism-shadow/penguin-harness/software-engineering/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.
<a href="https://agentmods.dev/skills/prism-shadow/penguin-harness/software-engineering"><img src="https://agentmods.dev/badge/skills/prism-shadow/penguin-harness/software-engineering.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 5.1 | $0.00035 | $0.00567 |
| Opus 5.5 | $0.00014 | $0.00227 |
| Sonnet 5.5 | $0.00007 | $0.00113 |
| Haiku 4.5 | $0.00003 | $0.00057 |
Grade A, and why
software-engineering 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 9d 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 — 32 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Software Engineering
This skill guides PenguinHarness through general software-engineering work, including code investigation, reviews, bug fixes, features, refactors, and verified handoff.
Before you start
If the user's message only invokes this skill without a concrete software-engineering task, ask what they want investigated, reviewed, fixed, or implemented. Do not start until the task is clear.
Workflow
- Match the work to the user's intent. For explanation, review, or planning requests, inspect and report without editing unless a change is also requested. For implementation tasks, carry the requested change through verification and handoff.
- Use the current working directory as the target project and work in place unless the user directs otherwise.
- Preserve worktree changes you did not make. Never revert unrelated user or collaborator work, and do not use destructive Git commands unless explicitly requested.
- Act autonomously and use tools to understand the real code. Resolve minor ambiguity from existing behavior, tests, and repository conventions; ask only when different choices would materially change the requested behavior or scope.
- Before making changes, read the applicable repository instructions (such as
AGENTS.mdorCLAUDE.md) and identify the repository-provided build, test, lint, and formatting commands. - Inspect the relevant implementation, callers, tests, and interfaces before making changes.
- For bug reports, try to reproduce the issue or identify a failing test before editing when feasible. Use the reproduced behavior or failing test to verify the fix afterward.
- Make the smallest coherent change that fully satisfies the request. Follow existing patterns and dependencies, preserve unrelated behavior, and update coupled tests, schemas, configuration, or generated artifacts only when the repository requires it. Never weaken a test to justify the implementation.
- For implementation tasks, do not stop after analysis. Inspect failures, revise the approach, and continue until the change is verified or a concrete blocker remains. Do not repeat a failed action without changing the approach.
- Validate code changes proportionally with repository-provided commands: run the most focused relevant check first and broaden only when useful. Preserve exit status, inspect relevant failure output, and never claim that an unobserved check passed.
- Before finishing a code change, review
git diffand repository status, remove temporary artifacts, and keep the change limited to the task. Do not commit unless the user or applicable repository instructions require it.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 9d ago Changed · +1 lines a0ce71bba7bd
- 1mo ago Changed · -4 lines 86b50545dad6
- 1mo ago First seen · 35 lines · 35 tokens per session scan A 279571dd8e0f
software-engineering is a skill published in the GitHub repository Prism-Shadow/penguin-harness (2,862 stars, last pushed today), licensed Apache-2.0. It adds 35 tokens to every session and 567 once invoked, about $0.0001 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 2026-08-30.
Other skills, from other repositories
agentscope-java
Expert Java developer skill for AgentScope Java framework - a reactive, message-driven multi-agent system built on Project Reactor. Use when working with reactive programming, LLM integration, agent orchestration, multi-agent systems, or when the user mentions AgentScope, ReActAgent, Mono/Flux, Project Reactor, or…
apply-patch
Apply multi-file or tricky edits atomically with git apply instead of many fragile editfile calls. Use when changing several files at once or when editfile fails to match.
git-checkpoint
Use git as a safety net - create a checkpoint commit before risky or large changes and roll back cleanly if a change makes things worse. Use before multi-file refactors.
pptagent
Create and revise editable PowerPoint presentations from a brief using HTML slide sources, rendering, and visual review. Use when the requested deliverable is a PPTX deck. The host authors the slides; text-only hosts can use an external visual reviewer.
agentfield-use
Whenever you have a discrete task to perform — one the user delegated, or one that arose inside your own work — check FIRST whether an installed AgentField agent covers it, and offload to it by default when one does. Coverage, not task size, is the test: even a small job goes to a covering agent. The check is cheap …
browser-workflow-skill-builder
Create robust browser automation skills for sites like LinkedIn, X/Twitter, YouTube, Stripe, or other logged-in web apps by saving page context, analyzing HTML/CSS, writing skill-local JS extract/verify scripts, and using CSS selector actions with screenshot verification.