Scatter-Gather Tool

# Scatter-Gather Tool

Fan out to multiple sources, then combine results.

## Category
Tool Composition

## Context
Querying multiple systems for related data.

## Problem
Gathering data from multiple sources requires multiple sequential calls.

## Solution
Scatter-Gather pattern:
- **Fan out**: Query multiple sources in parallel
- **Gather**: Combine results into unified response
- **Handle failures**: Partial results if some fail
- **Deduplicate**: Merge overlapping data

## Example (Python)
```python
@tool
async def search_all_repositories(
    query: str
) -> UnifiedSearchResult:
    """Search across GitHub, GitLab, and Bitbucket.
    
    Queries all configured repositories in parallel
    and returns unified results.
    """
    results = await asyncio.gather(
        search_github(query),
        search_gitlab(query),
        search_bitbucket(query),
        return_exceptions=True
    )
    return merge_results(results)
```

## Considerations
- Set timeouts for individual sources
- When appropriate, return partial results if some sources fail
- Indicate which sources contributed to results
- For long running queries, return a job ID and instructions for how to check the status and retrieve the results

## Related Patterns
- batch-operation
- partial-success
- graceful-degradation

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Source: https://arcade.dev/patterns/scatter-gather-tool