arcade-mcp/libs/arcade-cli/arcade_cli/formatters/json.py
jottakka 98fad93d21
Adding MCP Servers supports to Arcade Evals (#689)
# 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>
2026-01-07 20:26:23 -03:00

690 lines
26 KiB
Python

"""JSON formatter for evaluation and capture results."""
import json
from datetime import datetime, timezone
from typing import Any
from arcade_cli.formatters.base import (
CaptureFormatter,
CaptureResults,
EvalResultFormatter,
EvalResults,
EvalStats,
find_best_model,
group_comparative_by_case,
group_comparative_by_case_first,
group_eval_for_comparison,
group_results_by_model,
is_comparative_result,
is_multi_model_capture,
is_multi_model_comparative,
is_multi_model_eval,
)
class JsonFormatter(EvalResultFormatter):
"""
JSON formatter for evaluation results.
Produces a structured JSON document containing all evaluation data,
suitable for programmatic processing, dashboards, or further analysis.
"""
@property
def file_extension(self) -> str:
return "json"
def format(
self,
results: EvalResults,
show_details: bool = False,
failed_only: bool = False,
original_counts: EvalStats | None = None,
include_context: bool = False,
) -> str:
"""Format evaluation results as JSON."""
# Check if this is a comparative evaluation
if is_comparative_result(results):
output = self._format_comparative(
results, show_details, failed_only, original_counts, include_context
)
elif is_multi_model_eval(results):
output = self._format_multi_model(
results, show_details, failed_only, original_counts, include_context
)
else:
output = self._format_regular(
results, show_details, failed_only, original_counts, include_context
)
return json.dumps(output, indent=2, default=str)
def _format_regular(
self,
results: EvalResults,
show_details: bool = False,
failed_only: bool = False,
original_counts: EvalStats | None = None,
include_context: bool = False,
) -> dict[str, Any]:
"""Format regular (non-comparative) evaluation results."""
model_groups, total_passed, total_failed, total_warned, total_cases = (
group_results_by_model(results)
)
# Calculate pass rate
if total_cases > 0:
if failed_only and original_counts and original_counts[0] > 0:
pass_rate = (original_counts[1] / original_counts[0]) * 100
else:
pass_rate = (total_passed / total_cases) * 100
else:
pass_rate = 0
output: dict[str, Any] = {
"type": "evaluation",
"generated_at": datetime.now(timezone.utc).isoformat(),
"summary": {
"total_cases": total_cases,
"passed": total_passed,
"failed": total_failed,
"warned": total_warned,
"pass_rate": round(pass_rate, 2),
},
"models": {},
}
if failed_only and original_counts:
output["summary"]["original_counts"] = {
"total": original_counts[0],
"passed": original_counts[1],
"failed": original_counts[2],
"warned": original_counts[3],
}
output["summary"]["filtered"] = True
# Build model results
for model, suites in model_groups.items():
output["models"][model] = {"suites": {}}
for suite_name, cases in suites.items():
suite_data: dict[str, Any] = {
"case_count": len(cases),
"cases": [],
}
for case in cases:
case_data = self._serialize_case(case, show_details, include_context)
suite_data["cases"].append(case_data)
output["models"][model]["suites"][suite_name] = suite_data
return output
def _format_comparative(
self,
results: EvalResults,
show_details: bool = False,
failed_only: bool = False,
original_counts: EvalStats | None = None,
include_context: bool = False,
) -> dict[str, Any]:
"""Format comparative evaluation results."""
# Check if this is multi-model comparative - use case-first grouping
if is_multi_model_comparative(results):
return self._format_comparative_case_first(
results, show_details, failed_only, original_counts, include_context
)
return self._format_comparative_single_model(
results, show_details, failed_only, original_counts, include_context
)
def _format_comparative_single_model(
self,
results: EvalResults,
show_details: bool = False,
failed_only: bool = False,
original_counts: EvalStats | None = None,
include_context: bool = False,
) -> dict[str, Any]:
"""Format single-model comparative evaluation results."""
(
comparative_groups,
total_passed,
total_failed,
total_warned,
total_cases,
suite_track_order,
) = group_comparative_by_case(results)
# Collect all unique tracks
all_tracks: list[str] = []
for tracks in suite_track_order.values():
for t in tracks:
if t not in all_tracks:
all_tracks.append(t)
# Calculate pass rate
if total_cases > 0:
if failed_only and original_counts and original_counts[0] > 0:
pass_rate = (original_counts[1] / original_counts[0]) * 100
else:
pass_rate = (total_passed / total_cases) * 100
else:
pass_rate = 0
output: dict[str, Any] = {
"type": "comparative_evaluation",
"generated_at": datetime.now(timezone.utc).isoformat(),
"tracks": all_tracks,
"summary": {
"total_cases": total_cases,
"passed": total_passed,
"failed": total_failed,
"warned": total_warned,
"pass_rate": round(pass_rate, 2),
},
"models": {},
}
if failed_only and original_counts:
output["summary"]["original_counts"] = {
"total": original_counts[0],
"passed": original_counts[1],
"failed": original_counts[2],
"warned": original_counts[3],
}
output["summary"]["filtered"] = True
# Build model results
for model, suites in comparative_groups.items():
output["models"][model] = {"suites": {}}
for suite_name, cases in suites.items():
track_order = suite_track_order.get(suite_name, [])
suite_data: dict[str, Any] = {
"tracks": track_order,
"case_count": len(cases),
"cases": {},
}
for case_name, case_data in cases.items():
tracks_data = case_data.get("tracks", {})
case_output: dict[str, Any] = {
"input": case_data.get("input", ""),
"tracks": {},
}
# Add context if requested
if include_context:
system_msg = case_data.get("system_message")
addl_msgs = case_data.get("additional_messages")
if system_msg:
case_output["system_message"] = system_msg
if addl_msgs:
case_output["additional_messages"] = addl_msgs
for track_name in track_order:
if track_name not in tracks_data:
case_output["tracks"][track_name] = {"status": "missing"}
continue
track_result = tracks_data[track_name]
evaluation = track_result.get("evaluation")
if not evaluation:
case_output["tracks"][track_name] = {"status": "no_evaluation"}
continue
track_data: dict[str, Any] = {
"status": self._get_status(evaluation),
"score": round(evaluation.score * 100, 2),
"passed": evaluation.passed,
"warning": evaluation.warning,
}
if evaluation.failure_reason:
track_data["failure_reason"] = evaluation.failure_reason
if show_details and evaluation.results:
track_data["details"] = self._serialize_critic_results(
evaluation.results
)
case_output["tracks"][track_name] = track_data
suite_data["cases"][case_name] = case_output
output["models"][model]["suites"][suite_name] = suite_data
return output
def _format_comparative_case_first(
self,
results: EvalResults,
show_details: bool = False,
failed_only: bool = False,
original_counts: EvalStats | None = None,
include_context: bool = False,
) -> dict[str, Any]:
"""Format multi-model comparative evaluation grouped by case first."""
# Get case-first grouping
(
case_groups,
model_order,
suite_track_order,
total_passed,
total_failed,
total_warned,
total_cases,
) = group_comparative_by_case_first(results)
# Collect all unique tracks
all_tracks: list[str] = []
for tracks in suite_track_order.values():
for t in tracks:
if t not in all_tracks:
all_tracks.append(t)
# Calculate pass rate
if total_cases > 0:
if failed_only and original_counts and original_counts[0] > 0:
pass_rate = (original_counts[1] / original_counts[0]) * 100
else:
pass_rate = (total_passed / total_cases) * 100
else:
pass_rate = 0
output: dict[str, Any] = {
"type": "multi_model_comparative_evaluation",
"generated_at": datetime.now(timezone.utc).isoformat(),
"models": model_order,
"tracks": all_tracks,
"summary": {
"total_cases": total_cases,
"passed": total_passed,
"failed": total_failed,
"warned": total_warned,
"pass_rate": round(pass_rate, 2),
},
"grouped_by_case": {},
}
if failed_only and original_counts:
output["summary"]["original_counts"] = {
"total": original_counts[0],
"passed": original_counts[1],
"failed": original_counts[2],
"warned": original_counts[3],
}
output["summary"]["filtered"] = True
# Build case-first structure
for suite_name, cases in case_groups.items():
track_order = suite_track_order.get(suite_name, [])
output["grouped_by_case"][suite_name] = {"tracks": track_order, "cases": {}}
for case_name, model_data in cases.items():
first_model_data = next(iter(model_data.values()), {})
case_output: dict[str, Any] = {
"input": first_model_data.get("input", ""),
"models": {},
}
# Add context if requested
if include_context:
system_msg = first_model_data.get("system_message")
addl_msgs = first_model_data.get("additional_messages")
if system_msg:
case_output["system_message"] = system_msg
if addl_msgs:
case_output["additional_messages"] = addl_msgs
for model in model_order:
if model not in model_data:
case_output["models"][model] = {"status": "missing"}
continue
model_case_data = model_data[model]
tracks_data = model_case_data.get("tracks", {})
model_output: dict[str, Any] = {"tracks": {}}
for track_name in track_order:
if track_name not in tracks_data:
model_output["tracks"][track_name] = {"status": "missing"}
continue
track_result = tracks_data[track_name]
evaluation = track_result.get("evaluation")
if not evaluation:
model_output["tracks"][track_name] = {"status": "no_evaluation"}
continue
track_data: dict[str, Any] = {
"status": self._get_status(evaluation),
"score": round(evaluation.score * 100, 2),
"passed": evaluation.passed,
"warning": evaluation.warning,
}
if evaluation.failure_reason:
track_data["failure_reason"] = evaluation.failure_reason
if show_details and evaluation.results:
track_data["details"] = self._serialize_critic_results(
evaluation.results
)
model_output["tracks"][track_name] = track_data
case_output["models"][model] = model_output
output["grouped_by_case"][suite_name]["cases"][case_name] = case_output
return output
def _format_multi_model(
self,
results: EvalResults,
show_details: bool = False,
failed_only: bool = False,
original_counts: EvalStats | None = None,
include_context: bool = False,
) -> dict[str, Any]:
"""Format multi-model evaluation results with comparison structure."""
comparison_data, model_order, per_model_stats = group_eval_for_comparison(results)
# Calculate totals
total_passed = sum(s["passed"] for s in per_model_stats.values())
total_failed = sum(s["failed"] for s in per_model_stats.values())
total_warned = sum(s["warned"] for s in per_model_stats.values())
total_cases = sum(s["total"] for s in per_model_stats.values())
# Calculate pass rate
if total_cases > 0:
if failed_only and original_counts and original_counts[0] > 0:
pass_rate = (original_counts[1] / original_counts[0]) * 100
else:
pass_rate = (total_passed / total_cases) * 100
else:
pass_rate = 0
output: dict[str, Any] = {
"type": "multi_model_evaluation",
"generated_at": datetime.now(timezone.utc).isoformat(),
"models": model_order,
"summary": {
"total_evaluations": total_cases,
"unique_cases": sum(len(cases) for cases in comparison_data.values()),
"passed": total_passed,
"failed": total_failed,
"warned": total_warned,
"pass_rate": round(pass_rate, 2),
},
"per_model_stats": {},
"comparison": {},
}
if failed_only and original_counts:
output["summary"]["original_counts"] = {
"total": original_counts[0],
"passed": original_counts[1],
"failed": original_counts[2],
"warned": original_counts[3],
}
output["summary"]["filtered"] = True
# Per-model statistics
best_model = None
best_rate = -1.0
for model in model_order:
stats = per_model_stats[model]
output["per_model_stats"][model] = {
"total": stats["total"],
"passed": stats["passed"],
"failed": stats["failed"],
"warned": stats["warned"],
"pass_rate": round(stats["pass_rate"], 2),
}
if stats["pass_rate"] > best_rate:
best_rate = stats["pass_rate"]
best_model = model
if best_model:
output["summary"]["best_model"] = best_model
output["summary"]["best_pass_rate"] = round(best_rate, 2)
# Build comparison structure
for suite_name, cases in comparison_data.items():
output["comparison"][suite_name] = {}
for case_name, case_models in cases.items():
case_output: dict[str, Any] = {
"results_by_model": {},
}
# Add context from first model if requested
if include_context:
first_model_result = next(iter(case_models.values()), {})
system_msg = first_model_result.get("system_message")
addl_msgs = first_model_result.get("additional_messages")
if system_msg:
case_output["system_message"] = system_msg
if addl_msgs:
case_output["additional_messages"] = addl_msgs
for model in model_order:
if model not in case_models:
case_output["results_by_model"][model] = {"status": "missing"}
continue
case_result = case_models[model]
evaluation = case_result["evaluation"]
model_data: dict[str, Any] = {
"status": self._get_status(evaluation),
"score": round(evaluation.score * 100, 2),
"passed": evaluation.passed,
"warning": evaluation.warning,
}
if evaluation.failure_reason:
model_data["failure_reason"] = evaluation.failure_reason
if show_details and evaluation.results:
model_data["details"] = self._serialize_critic_results(evaluation.results)
case_output["results_by_model"][model] = model_data
# Find best model for this case
best, best_score = find_best_model(case_models)
case_output["best_model"] = best
case_output["best_score"] = round(best_score * 100, 2)
output["comparison"][suite_name][case_name] = case_output
return output
def _serialize_case(
self, case: dict[str, Any], show_details: bool, include_context: bool = False
) -> dict[str, Any]:
"""Serialize a single evaluation case."""
evaluation = case["evaluation"]
case_data: dict[str, Any] = {
"name": case["name"],
"input": case.get("input", ""),
"status": self._get_status(evaluation),
"score": round(evaluation.score * 100, 2),
"passed": evaluation.passed,
"warning": evaluation.warning,
}
# Add context if requested
if include_context:
system_msg = case.get("system_message")
addl_msgs = case.get("additional_messages")
if system_msg:
case_data["system_message"] = system_msg
if addl_msgs:
case_data["additional_messages"] = addl_msgs
if evaluation.failure_reason:
case_data["failure_reason"] = evaluation.failure_reason
if show_details and evaluation.results:
case_data["details"] = self._serialize_critic_results(evaluation.results)
return case_data
def _serialize_critic_results(self, results: list[dict[str, Any]]) -> list[dict[str, Any]]:
"""Serialize critic results for detailed output."""
serialized = []
for critic_result in results:
item: dict[str, Any] = {
"field": critic_result["field"],
"match": critic_result["match"],
"score": critic_result["score"],
"weight": critic_result["weight"],
"expected": critic_result["expected"],
"actual": critic_result["actual"],
}
if "is_criticized" in critic_result:
item["is_criticized"] = critic_result["is_criticized"]
serialized.append(item)
return serialized
def _get_status(self, evaluation: Any) -> str:
"""Get status string from evaluation."""
if evaluation.passed:
return "passed"
elif evaluation.warning:
return "warned"
else:
return "failed"
class CaptureJsonFormatter(CaptureFormatter):
"""JSON formatter for capture results."""
@property
def file_extension(self) -> str:
return "json"
def format(
self,
captures: CaptureResults,
include_context: bool = False,
) -> str:
"""Format capture results as JSON."""
# Check for multi-model captures
if is_multi_model_capture(captures):
output_data = self._format_multi_model(captures, include_context)
else:
output_data = {
"type": "capture",
"captures": [cap.to_dict(include_context=include_context) for cap in captures],
}
return json.dumps(output_data, indent=2)
def _format_multi_model(
self,
captures: CaptureResults,
include_context: bool = False,
) -> dict[str, Any]:
"""Format multi-model capture results with track-aware structure."""
from arcade_cli.formatters.base import group_captures_by_case_then_track
grouped_data, model_order, track_order = group_captures_by_case_then_track(captures)
has_tracks = len(track_order) > 1 or (track_order and track_order[0] is not None)
track_names = [t for t in track_order if t is not None] if has_tracks else []
output: dict[str, Any] = {
"type": "multi_model_capture",
"generated_at": datetime.now(timezone.utc).isoformat(),
"models": model_order,
"tracks": track_names if track_names else None,
"summary": {
"total_suites": len(grouped_data),
"total_cases": sum(len(cases) for cases in grouped_data.values()),
"models_count": len(model_order),
"tracks_count": len(track_names) if track_names else 0,
},
"grouped_by_case": {},
}
for suite_name, cases in grouped_data.items():
output["grouped_by_case"][suite_name] = {}
for case_name, case_data in cases.items():
case_output: dict[str, Any] = {
"user_message": case_data.get("user_message", ""),
}
if include_context:
if case_data.get("system_message"):
case_output["system_message"] = case_data["system_message"]
if case_data.get("additional_messages"):
case_output["additional_messages"] = case_data["additional_messages"]
tracks_data = case_data.get("tracks", {})
track_keys = list(tracks_data.keys())
has_multiple_tracks = len(track_keys) > 1 or (
len(track_keys) == 1 and track_keys[0] != "_default"
)
if has_multiple_tracks:
# Structure with tracks
case_output["tracks"] = {}
for track_key in track_keys:
track_display = track_key if track_key != "_default" else "default"
track_data = tracks_data[track_key]
models_dict = track_data.get("models", {})
track_output: dict[str, Any] = {"models": {}}
for model in model_order:
if model not in models_dict:
track_output["models"][model] = {"status": "missing"}
continue
captured_case = models_dict[model]
track_output["models"][model] = {
"tool_calls": [
{"name": tc.name, "args": tc.args}
for tc in captured_case.tool_calls
],
}
case_output["tracks"][track_display] = track_output
else:
# No tracks - flat structure
track_key = track_keys[0] if track_keys else "_default"
track_data = tracks_data.get(track_key, {})
models_dict = track_data.get("models", {})
case_output["models"] = {}
for model in model_order:
if model not in models_dict:
case_output["models"][model] = {"status": "missing"}
continue
captured_case = models_dict[model]
case_output["models"][model] = {
"tool_calls": [
{"name": tc.name, "args": tc.args}
for tc in captured_case.tool_calls
],
}
output["grouped_by_case"][suite_name][case_name] = case_output
return output