Agent Playground
FreeNot checkedLLM Harness for developing, debugging, and evaluating custom agents, tools, MCP servers, prompts, and memory constructs using Anthropic, OpenAI, or a local mode
About
LLM Harness for developing, debugging, and evaluating custom agents, tools, MCP servers, prompts, and memory constructs using Anthropic, OpenAI, or a local model.
README
Branded multi-provider agent harness — chat, tools, MCP servers, and auto-saved transcripts — for experimenting with agentic systems against Anthropic, OpenAI, and locally-hosted models (vLLM, LM Studio, llama.cpp, anything OpenAI-compatible).
Setup
# 1. Activate the project venv (Python 3.14)
source .agent-playground/bin/activate
# 2. Install
pip install -e ".[dev]"
# 3. Configure
cp .env.example .env
$EDITOR .env # set ANTHROPIC_API_KEY / OPENAI_API_KEY / LOCAL_BASE_URL
Run
streamlit run app.py
Opens a browser on http://localhost:8501. Click Basic Chat in the sidebar.
Smoke-test without the GUI
python -m playground.smoke --provider anthropic --prompt "Say hi"
Run the test suite
pytest
Add a local tool
Create a Python file under playground/tools/examples/ (or anywhere; just
make sure it gets imported):
from playground.tools import register_tool
@register_tool
def reverse_string(s: str) -> str:
"""Reverse a string."""
return s[::-1]
Add the import to playground/tools/examples/__init__.py. Refresh the
chat page — the tool appears in "Local tools" and the LLM can call it.
Add an MCP server
Edit mcp.json:
{
"mcpServers": {
"filesystem": {
"command": "npx",
"args": ["-y", "@modelcontextprotocol/server-filesystem", "/tmp/fs"],
"description": "Read/write files under /tmp/fs",
"enabled": true
}
}
}
Click Reload mcp.json in Basic Chat's sidebar.
Layout
app.py— Home pagepages/1_Basic_Chat.py— the MVP chat pageplayground/— shared package: providers, tools, prompts, MCP, persistencemcp_servers/notes/— bundled MCP server (agent scratch notes)conversations/— auto-saved JSON transcripts (gitignored)tests/— pytest suitedocs/superpowers/— design specs and implementation plans
Memory + Dreaming
The bundled memory MCP server gives the playground agent persistent
cross-conversation memory. A separate background dreamer process runs a
six-stage consolidation cycle that produces a bi-temporal knowledge
graph plus speculative hypotheses you can curate from the new
Dreaming page.
Quick start:
- Set
LOCAL_BASE_URLto your local OpenAI-compatible inference server (vLLM, LM Studio, llama.cpp, etc.). streamlit run app.py— the memory server starts automatically.- Send a few messages in Basic Chat. Then open Dreaming → click Start daemon and Dream now (full).
Design: docs/superpowers/specs/2026-05-11-memory-dreaming-mcp-design.md.
Spec
Full v1 design: docs/superpowers/specs/2026-05-09-travisml-agent-playground-design.md.
Installing Agent Playground
This server has no published package — it is built from source. Open the repository and follow its README.
▸ github.com/Travis-ML/agent-playgroundFAQ
Is Agent Playground MCP free?
Yes, Agent Playground MCP is free — one-click install via Unyly at no cost.
Does Agent Playground need an API key?
No, Agent Playground runs without API keys or environment variables.
Is Agent Playground hosted or self-hosted?
Self-hosted: the server runs locally on your machine via the install command above.
How do I install Agent Playground in Claude Desktop, Claude Code or Cursor?
Open Agent Playground on unyly.org, pick your client tab (Claude Desktop, Claude Code, Cursor) and press Install — the config is generated automatically, no JSON editing.
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