Deploy and serve LLMs with vLLM behind an OpenAI-compatible endpoint, with tool calling enabled for agent workloads.

Apache-2.0Auto-check passedAI & LLM Engineering

Install Vllm

skills CLI
$ npx skills add Prism-Shadow/penguin-harness --skill vllm -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install Prism-Shadow/penguin-harness vllm --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/Prism-Shadow/penguin-harness.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/model-development/skills/vllm .claude/skills/vllm && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
vllm
GitHub stars
2.5k
Token cost
~1k tokens
SKILL.md length
461 words
Files
1
Skills in repo
31
Repo updated
First seen
Licence
Apache-2.0

At a glance

Deploy and serve LLMs with vLLM behind an OpenAI-compatible endpoint, with tool calling enabled for agent workloads.

  • Works in 6 steps: Ask the user which model to serve; with… → Pick the engine the user prefers: vLLM… → Serve on a free port, with the… → …
  • Tasks that involve LLM inference and serving
  • SKILL.md covers Before you start, Suggested workflow, Install and Serve, plus 4 more sections
  • Calls python3, curl and pip

What it does

Vllm is an agent skill from Prism-Shadow/penguin-harness. Deploy and serve LLMs with vLLM behind an OpenAI-compatible endpoint, with tool calling enabled for agent workloads.

Its SKILL.md is about 1k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in AI & LLM Engineering, covering LLM inference and serving and Structured output and tool calling. It works with vLLM, OpenAI, Qwen and Ollama. The repository describes itself as: 🐧 Unified and Stable RSI Platform. The licence is Apache-2.0.

When your agent uses it

  • Tasks that involve LLM inference and serving
  • Tasks that involve Structured output and tool calling

Example prompts

  • “/vllm”

Requirements

  • Python 3

Workflow steps

6 steps, taken from the first numbered list in SKILL.md.

  1. Ask the user which model to serve; with no preference, recommend Qwen/Qwen3.5-0.8B.
  2. Pick the engine the user prefers: vLLM for high-throughput GPU serving; Ollama is the simple default and the choice on macOS or CPU-only…
  3. Serve on a free port, with the tool-calling flags whenever agents will call it (see below).
  4. Verify with curl http://localhost:8000/v1/models.
  5. Register the endpoint: penguin config model add ... --client-type openai-chat --base-url http://localhost:8000/v1 — a served model is not…
  6. Confirm the new entry with penguin config model list.

What it can do on your machine

Read from SKILL.md and the folder at commit d56d9ce. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • python3
    • curl
    • pip

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    Links to these hosts (documentation or services it may open):

    • huggingface.co

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Vllm loads about 1k tokens when it runs. Until then it costs about 30 tokens; SKILL.md has 461 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~30
When it runs · the whole SKILL.md, loaded when a task matches
~1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from Prism-Shadow/penguin-harness at commit d56d9ce, republished under its Apache-2.0 licence (© Prism-Shadow). 461 words, ~1,026 tokens.

Download SKILL.mdSave it as .claude/skills/vllm/SKILL.md (or your agent's skills folder).
name
vllm
description
Deploy and serve LLMs with vLLM behind an OpenAI-compatible endpoint, with tool calling enabled for agent workloads.

vLLM Serving

vLLM serves open-weight LLMs on local GPUs with high-throughput inference behind an OpenAI-compatible API, ready for chat and agent workloads.

Before you start

If the user's message only invokes this skill (e.g. "use vllm skill") without a concrete request, ask the user what they want. Do not run any command until the goal is clear.

Ask the user which model to serve; if they have no preference, recommend the small default Qwen/Qwen3.5-0.8B. Also ask what context length the workload needs.

vLLM needs an NVIDIA or AMD GPU. Engine choice follows the user's preference: Ollama also runs on GPUs and is the simpler default — pick vLLM for high-throughput serving, and Ollama on macOS or CPU-only machines, which vLLM does not serve. Confirm the hardware first:

bash
nvidia-smi          # NVIDIA: GPU model and free VRAM (AMD ROCm: rocm-smi)
python3 --version   # a recent Python is required

The model must fit the available VRAM — model size and context length drive the serve flags below.

Suggested workflow

  1. Ask the user which model to serve; with no preference, recommend Qwen/Qwen3.5-0.8B.
  2. Pick the engine the user prefers: vLLM for high-throughput GPU serving; Ollama is the simple default and the choice on macOS or CPU-only machines.
  3. Serve on a free port, with the tool-calling flags whenever agents will call it (see below).
  4. Verify with curl http://localhost:8000/v1/models.
  5. Register the endpoint: penguin config model add ... --client-type openai-chat --base-url http://localhost:8000/v1 — a served model is not visible to Penguin until added.
  6. Confirm the new entry with penguin config model list.

Install

Use a fresh virtual environment (or uv):

bash
python3 -m venv .venv && source .venv/bin/activate
pip install vllm
Show full SKILL.md (216 more words)Show less

Serve

bash
vllm serve Qwen/Qwen3.5-0.8B --port 8000

This exposes an OpenAI-compatible API at http://localhost:8000/v1. Key flags:

  • --served-model-name <name> — the model id clients request (defaults to the model path).
  • --api-key <key> — require this bearer token on every request.
  • --max-model-len <n> — context window; agent sessions need a large one.
  • --gpu-memory-utilization <0..1> — fraction of VRAM to claim (default 0.9).
  • --tensor-parallel-size <n> — shard across n GPUs.
  • --dtype <auto|bfloat16|float16> and --quantization <awq|gptq|fp8> — precision and quantized weights.

If the port is taken, pick a free one — never kill a process already listening on it.

Tool calling — required for agents

Agent harnesses (PenguinHarness included) send tools with their requests. vLLM must opt in at startup:

bash
vllm serve Qwen/Qwen3.5-0.8B --enable-auto-tool-choice --tool-call-parser hermes

Choose the parser for the model family — e.g. hermes for Qwen models, llama3_json for Llama models. Without these flags, requests that set tool_choice fail with 400 "auto" tool choice requires --enable-auto-tool-choice and --tool-call-parser to be set.

Verify

bash
curl http://localhost:8000/v1/models

Register with PenguinHarness

Model configuration is the penguin CLI's job — penguin config model add registers an endpoint and penguin config model list shows what has been registered. A served model is not visible to Penguin until you add it:

bash
penguin config model add --provider custom --client-type openai-chat \
  --base-url http://localhost:8000/v1 --model-id <served-model-name> --api-key <key>
penguin config model list   # the new entry should now be listed

Troubleshooting

  • Out of memory at startup: lower --gpu-memory-utilization or --max-model-len, or serve a quantized model.
  • Long prompts truncated or context-length errors: raise --max-model-len (bounded by VRAM).
  • 400 on tool calls: restart the server with the tool-calling flags above.

© Prism-Shadow, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in plugins/model-development/skills/vllm of Prism-Shadow/penguin-harness.

Open the folder on GitHubat commit d56d9ce

Compare with similar skills

Vllm next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Vllm compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Vllm this skillPrism-Shadow/penguin-harness2.5k—~1kAutomated safety check: PassApache-2.0
Aider DelegateamElnagdy/delegate-skills2.3k3 repos~3kAutomated safety check: PassMIT
Perfupraullenchai/Rapid-MLX3.9k—~1.6kAutomated safety check: NotesCustom licence
Resolvealexziskind1/model-shelf130—~792Automated safety check: PassMIT
Tanstack AIsecondsky/claude-skills2271 repos~3.6kAutomated safety check: NotesMIT
Vllm Ascendascend-ai-coding/awesome-ascend-skills174—~2.7kAutomated safety check: PassNone

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Questions about Vllm

What does Vllm do?

Deploy and serve LLMs with vLLM behind an OpenAI-compatible endpoint, with tool calling enabled for agent workloads. Vllm is an agent skill from Prism-Shadow/penguin-harness. Deploy and serve LLMs with vLLM behind an OpenAI-compatible endpoint, with tool calling enabled for agent workloads.

When should I use Vllm?

Vllm fits situations like: tasks that involve LLM inference and serving; tasks that involve Structured output and tool calling.

How do I install Vllm in Claude Code?

Run `npx skills add Prism-Shadow/penguin-harness --skill vllm -a claude-code`. Or copy the skill folder (plugins/model-development/skills/vllm in Prism-Shadow/penguin-harness) into .claude/skills/vllm in your project. Claude Code loads it when a task matches its description.

How do I install Vllm in Codex?

Run `npx skills add Prism-Shadow/penguin-harness --skill vllm -a codex`. Or copy the skill folder (plugins/model-development/skills/vllm in Prism-Shadow/penguin-harness) into .agents/skills/vllm in your project. Codex loads it when a task matches its description.

Can I use Vllm in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add Prism-Shadow/penguin-harness --skill vllm -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/vllm, .gemini/skills/vllm, .github/skills/vllm and .opencode/skills/vllm in your project.

What does Vllm need to run?

Going by SKILL.md and its folder, Vllm needs the command-line tools its instructions call (python3, curl and pip). Our summary lists: Python 3.

Does Vllm access the network?

SKILL.md names 1 domain. As links in the text: huggingface.co. This is read from the text; nothing was executed.

Is Vllm safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Vllm use?

Vllm is published under the Apache-2.0 licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Vllm use?

About 1k tokens (SKILL.md is roughly 4.1k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Vllm?

Skills that share tags, products or a category with Vllm: Aider Delegate (amElnagdy/delegate-skills, 2.3k stars), Perfup (raullenchai/Rapid-MLX, 3.9k stars), Resolve (alexziskind1/model-shelf, 130 stars) and Tanstack AI (secondsky/claude-skills, 227 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Vllm?

Prism-Shadow (a GitHub organization) maintains it in Prism-Shadow/penguin-harness, which has 2,455 GitHub stars. The repository holds 31 skills in this directory. The repository was last updated on October 7, 2026.

Source: Prism-Shadow/penguin-harness on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.