# MCP Server Tool Evaluation Support
## Overview
Add support for evaluating tools from remote MCP servers without
requiring Python callables. Enables direct evaluation of any
MCP-compatible tool server.
## What's New
### Core Features
- **`MCPToolRegistry`**: Evaluate tools from a single MCP server
- **`CompositeMCPRegistry`**: Evaluate tools from multiple MCP servers
simultaneously
- **Automatic loaders**: `load_from_stdio()` and `load_from_http()` to
fetch tools from running servers
- **Automatic namespacing**: Tools prefixed with server name (e.g.,
`server_tool_name`)
- **Smart name resolution**: Use short names if unique, full names if
ambiguous
- **OpenAI strict mode**: Automatic schema conversion prevents parameter
hallucinations
### Usage
**Automatic Loading:**
```python
from arcade_evals import load_from_stdio, MCPToolRegistry
# Load tools automatically from MCP server
tools = load_from_stdio(["npx", "-y", "@modelcontextprotocol/server-github"])
registry = MCPToolRegistry(tools)
```
**Single MCP Server:**
```python
from arcade_evals import MCPToolRegistry, ExpectedToolCall
registry = MCPToolRegistry(mcp_tools)
suite = EvalSuite(catalog=registry)
suite.add_case(
expected_tool_calls=[
ExpectedToolCall(tool_name="tool_name", args={...})
]
)
```
**Multiple MCP Servers:**
```python
from arcade_evals import CompositeMCPRegistry, load_from_stdio
# Load from multiple servers
github_tools = load_from_stdio(["npx", "-y", "@modelcontextprotocol/server-github"])
slack_tools = load_from_stdio(["npx", "-y", "@modelcontextprotocol/server-slack"])
composite = CompositeMCPRegistry(
tool_lists={
"github": github_tools,
"slack": slack_tools,
}
)
suite = EvalSuite(catalog=composite)
suite.add_case(
expected_tool_calls=[
ExpectedToolCall(tool_name="github_list_issues", args={...})
]
)
```
## Implementation
### Files Changed
- **`libs/arcade-evals/arcade_evals/registry.py`** (NEW): Registry
abstractions and implementations
- **`libs/arcade-evals/arcade_evals/loaders.py`** (NEW): Automatic tool
loading from MCP servers
- **`libs/arcade-evals/arcade_evals/eval.py`** (MODIFIED): Enhanced
`ExpectedToolCall` and evaluation logic
- **`libs/arcade-evals/arcade_evals/__init__.py`** (MODIFIED): Exported
new registries and loaders
### Key Technical Details
- Added `BaseToolRegistry` interface for abstraction
- `MCPToolRegistry` handles single server tools
- `CompositeMCPRegistry` manages multiple servers with collision
detection
- `load_from_stdio()` and `load_from_http()` for automatic tool
discovery
- Fixed name normalization bug: MCP tools use underscores (not dots)
- Optimized tool copying: 2.5x faster via shallow copy
## Testing
- ✅ 41 tests passing (25 new tests added)
- ✅ `test_eval_mcp_registry.py`: MCPToolRegistry functionality
- ✅ `test_eval_composite_mcp.py`: CompositeMCPRegistry with multiple
servers
- ✅ Verified backward compatibility with Python tools
## Backward Compatibility
✅ **100% backward compatible** - No breaking changes
## Breaking Changes
**None**
<!-- CURSOR_SUMMARY -->
---
> [!NOTE]
> Adds end-to-end eval UX: examples, a robust CLI runner, and rich
outputs.
>
> - **New examples**: `eval_arcade_gateway.py`,
`eval_stdio_mcp_server.py`, `eval_http_mcp_server.py`,
`eval_comprehensive_comparison.py` with timeouts, error handling, and
track-based comparisons; detailed `README.md`
> - **CLI runner**: `arcade_cli/evals_runner.py` to execute
evals/capture in parallel with progress, error isolation, failed-only
filtering, context inclusion, and multi-provider/model support
> - **Output formatters**: `arcade_cli/formatters/` (txt, md, html,
json) for evals and capture; comparative and multi-model HTML with tabs
and context rendering
> - **Display refactor**: `display.py` now supports writing multiple
formats, failed-only disclaimers, include-context, and improved console
summaries
>
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
ff8acf9c34a6b61462a019a1ee9df081006517d0. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->
---------
Co-authored-by: Francisco Liberal <francisco@arcade.dev>
Co-authored-by: Mateo Torres <torresmateo@gmail.com>
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Markdown
392 lines
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# Arcade Evals Examples
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This directory contains user-friendly examples demonstrating how to evaluate tools from different sources using the Arcade evals framework.
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## 📋 Table of Contents
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- [Quick Start](#quick-start)
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- [Example Files](#example-files)
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- [CLI Reference](#cli-reference)
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- [Common Patterns](#common-patterns)
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- [Troubleshooting](#troubleshooting)
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## 🚀 Quick Start
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### What Makes These Examples Different
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These examples are designed to be:
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- **Production-ready**: Include proper error handling and timeouts
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- **Copy-paste friendly**: Clear configuration sections you can modify
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- **Informative**: Print status messages during loading
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- **Focused**: One concept per example, no unnecessary complexity
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- **Pattern-based**: Follow consistent structure from real-world evals
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### Installation
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```bash
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# Install with evals support
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pip install 'arcade-mcp[evals]'
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# Or using uv (recommended)
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uv tool install 'arcade-mcp[evals]'
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```
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### Basic Usage
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```bash
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# Run an evaluation with OpenAI
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arcade evals examples/evals/eval_arcade_gateway.py \
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--api-key openai:YOUR_OPENAI_KEY
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# Compare multiple models
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arcade evals examples/evals/eval_stdio_mcp_server.py \
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-p "openai:gpt-4o anthropic:claude-sonnet-4-5-20250929" \
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-k openai:YOUR_OPENAI_KEY \
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-k anthropic:YOUR_ANTHROPIC_KEY
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# Output results to HTML
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arcade evals examples/evals/eval_http_mcp_server.py \
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--api-key openai:YOUR_KEY \
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-o results.html -d
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```
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## 📚 Example Files
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### Example Structure
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All examples follow a consistent pattern:
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```python
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# 1. Configuration section - Update these values
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ARCADE_API_KEY = os.environ.get("ARCADE_API_KEY", "YOUR_KEY_HERE")
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# 2. Eval suite with async loading
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@tool_eval()
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async def eval_my_suite() -> EvalSuite:
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suite = EvalSuite(name="...", system_message="...", rubric=...)
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# 3. Load tools with timeout and error handling
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try:
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await asyncio.wait_for(
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suite.add_arcade_gateway(...),
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timeout=10.0,
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)
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print(" ✓ Source loaded")
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except Exception as e:
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print(f" ✗ Source failed: {e}")
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return suite
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# 4. Add test cases
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suite.add_case(name="...", user_message="...", ...)
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return suite
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```
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This pattern ensures:
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- Clear configuration at the top
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- Robust error handling
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- Informative output during loading
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- Graceful degradation if sources fail
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### 1. `eval_arcade_gateway.py`
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Evaluates tools from Arcade Gateway (cloud-hosted toolkits).
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**What it demonstrates:**
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- Async loading from Arcade Gateway with timeout handling
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- Error handling for connection failures
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- Math toolkit evaluations
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- BinaryCritic for parameter validation
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- Conversational context with additional_messages
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**Prerequisites:**
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Before running this example, you need to set up an MCP Gateway:
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1. **Get your API key** - [API Keys Setup Guide](https://docs.arcade.dev/en/get-started/setup/api-keys)
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2. **Create an MCP Gateway** at [Arcade Portal](https://portal.arcade.dev)
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3. **Add toolkits** (e.g., Math, GitHub, Slack) to your gateway
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4. **Get your credentials:**
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- `ARCADE_API_KEY` - Your Arcade API key
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- `ARCADE_USER_ID` - Your user ID (found in portal settings)
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📚 **Full setup guide:** [MCP Gateways Documentation](https://docs.arcade.dev/en/guides/create-tools/mcp-gateways)
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**Requirements:**
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- Arcade API key (get one at [arcade.dev](https://arcade.dev))
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- LLM API key (OpenAI or Anthropic)
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**Run it:**
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```bash
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# Set your Arcade API key
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export ARCADE_API_KEY=your_arcade_key
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arcade evals examples/evals/eval_arcade_gateway.py \
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--api-key openai:YOUR_OPENAI_KEY
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```
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### 2. `eval_stdio_mcp_server.py`
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Evaluates tools from local MCP servers running via stdio (subprocess).
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**What it demonstrates:**
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- Loading from local stdio MCP servers (subprocesses)
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- Using `add_mcp_stdio_server()` method
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- Setting environment variables (PYTHONUNBUFFERED)
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- Simple echo tool evaluations
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- Async loading with timeout and error handling
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**Requirements:**
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- Local MCP server code
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- Server dependencies installed
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- LLM API key
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**Run it:**
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```bash
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arcade evals examples/evals/eval_stdio_mcp_server.py \
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--api-key openai:YOUR_KEY
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```
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### 3. `eval_http_mcp_server.py`
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Evaluates tools from remote MCP servers via HTTP or SSE.
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**What it demonstrates:**
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- Connecting to HTTP MCP endpoints
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- Using SSE (Server-Sent Events) transport
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- Authentication with Bearer tokens
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- Error handling with timeouts
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**Requirements:**
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- Running HTTP/SSE MCP server
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- Network connectivity
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- LLM API key
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- (Optional) Authentication token
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**Run it:**
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```bash
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# Update the configuration in the file first, then run:
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arcade evals examples/evals/eval_http_mcp_server.py \
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--api-key openai:YOUR_KEY
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```
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### 4. `eval_comprehensive_comparison.py`
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Compares tool performance across multiple sources simultaneously.
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**What it demonstrates:**
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- Comparative evaluation across different tool sources
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- Loading from multiple sources (Gateway, stdio, dict)
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- Track-based evaluation (comparing same task across sources)
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- Conditional test cases based on loaded sources
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- Using SimilarityCritic for fuzzy matching
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**Requirements:**
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- Arcade API key (for Gateway)
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- LLM API key
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- (Optional) Local simple MCP server
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**Run it:**
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```bash
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# Set environment variables
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export ARCADE_API_KEY=your_key
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export ARCADE_USER_ID=your_user_id
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arcade evals examples/evals/eval_comprehensive_comparison.py \
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-p "openai:gpt-4o anthropic:claude-sonnet-4-5-20250929" \
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-k openai:YOUR_KEY \
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-k anthropic:YOUR_KEY \
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-o comparison.html -d
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```
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## 🎯 CLI Reference
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### New v2.0.0 Flags
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| Flag | Short | Description | Example |
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| --------------------- | ------- | -------------------------------------------------- | ------------------------------------------------- |
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| `--use-provider` | `-p` | Provider(s) and models (space-separated) | `-p "openai:gpt-4o anthropic:claude-sonnet"` |
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| `--api-key` | `-k` | API key in`provider:key` format (repeatable) | `-k openai:sk-... -k anthropic:sk-ant-...` |
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| `--output` | `-o` | Output file (auto-detects format from extension) | `-o results.html` or `-o results` (all formats) |
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| `--only-failed` | `-f` | Show only failed evaluations | `--only-failed` |
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| `--include-context` | | Include system messages and conversation history | `--include-context` |
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| `--details` | `-d` | Show detailed output | `-d` |
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| `--max-concurrent` | | Max concurrent evaluations | `--max-concurrent 5` |
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| `--capture` | | Capture mode (record tool calls without scoring) | `--capture` |
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### Provider & Model Selection
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**Single provider with default model:**
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```bash
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arcade evals eval_file.py -p openai -k openai:YOUR_KEY
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```
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**Single provider with specific models:**
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```bash
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arcade evals eval_file.py -p "openai:gpt-4o,gpt-4o-mini" -k openai:YOUR_KEY
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```
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**Multiple providers (space-separated):**
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```bash
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arcade evals eval_file.py \
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-p "openai:gpt-4o anthropic:claude-sonnet-4-5-20250929" \
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-k openai:YOUR_KEY \
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-k anthropic:YOUR_KEY
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```
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### Output Formats
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**Auto-detect from extension:**
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```bash
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-o results.html # HTML output
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-o results.json # JSON output
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-o results.md # Markdown output
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-o results.txt # Text output
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```
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**Multiple formats:**
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```bash
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-o results.html -o results.json # Both HTML and JSON
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```
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**All formats:**
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```bash
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-o results # Generates results.txt, results.md, results.html, results.json
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```
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## 🔧 Common Patterns
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### Pattern 1: Compare OpenAI Models
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```bash
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arcade evals examples/evals/eval_arcade_gateway.py \
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-p "openai:gpt-4o,gpt-4o-mini,gpt-3.5-turbo" \
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-k openai:YOUR_KEY \
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-o comparison.html -d
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```
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### Pattern 2: OpenAI vs Anthropic
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```bash
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arcade evals examples/evals/eval_stdio_mcp_server.py \
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-p "openai:gpt-4o anthropic:claude-sonnet-4-5-20250929" \
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-k openai:YOUR_OPENAI_KEY \
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-k anthropic:YOUR_ANTHROPIC_KEY \
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-o battle.html -d
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```
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### Pattern 3: Failed Tests Only
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```bash
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arcade evals examples/evals/eval_http_mcp_server.py \
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--api-key openai:YOUR_KEY \
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--only-failed -d
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```
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### Pattern 4: Comparative Evaluation
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```bash
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# Compare performance across multiple tool sources
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arcade evals examples/evals/eval_comprehensive_comparison.py \
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-p "openai:gpt-4o anthropic:claude-sonnet-4-5-20250929" \
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-k openai:YOUR_KEY \
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-k anthropic:YOUR_KEY \
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-o comparison.html -d
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```
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### Pattern 5: Capture Mode (No Scoring)
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```bash
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# Record tool calls without evaluation
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arcade evals examples/evals/eval_arcade_gateway.py \
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--capture \
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--api-key openai:YOUR_KEY \
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-o captured.json
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```
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### Pattern 6: Full Context Output
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```bash
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arcade evals examples/evals/eval_stdio_mcp_server.py \
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--api-key openai:YOUR_KEY \
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--include-context \
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-o full_results.html -d
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```
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## 🐛 Troubleshooting
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### Error: "No module named 'openai'"
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**Solution:** Install evals dependencies:
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```bash
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pip install 'arcade-mcp[evals]'
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```
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### Error: "API key not found for provider 'openai'"
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**Solution:** Provide API key via flag or environment variable:
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```bash
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# Via flag
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arcade evals eval_file.py --api-key openai:YOUR_KEY
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# Via environment variable
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export OPENAI_API_KEY=your_key
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arcade evals eval_file.py
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```
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### Error: "Connection refused" (HTTP server)
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**Solution:** Ensure your HTTP MCP server is running:
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```bash
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# Check if server is running
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curl http://localhost:8000/mcp
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# Start your server first
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python server.py
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```
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### Error: "Module not found" (stdio server)
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**Solution:** Install server dependencies:
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```bash
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cd examples/mcp_servers/simple
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uv sync
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```
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### Evals run but all tests fail
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**Possible causes:**
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1. Wrong tool names - check your server's tool definitions
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2. Incorrect argument names - verify expected vs actual
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3. Server not responding - check server logs
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4. API key issues - verify LLM provider keys
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**Debug with verbose output:**
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```bash
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arcade evals eval_file.py --api-key openai:YOUR_KEY -d
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```
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