> ## Documentation Index
> Fetch the complete documentation index at: https://rekko.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Expand Parameter

> Request additional nested data with ?expand=.

Many endpoints support the `?expand=` query parameter to include additional nested data in the response. This keeps default responses lightweight while giving you access to deeper information on demand.

## Usage

Pass a comma-separated list of expansion names:

```bash theme={null}
curl "https://api.rekko.ai/v1/markets/kalshi/KXFED-26MAR19/analysis?expand=causal,scenarios,meta" \
  -H "Authorization: Bearer YOUR_API_KEY"
```

## Available expansions

| Expansion   | Available on      | Description                                                                                                          |
| ----------- | ----------------- | -------------------------------------------------------------------------------------------------------------------- |
| `causal`    | Analysis, Signals | [Causal factor decomposition](/concepts/causal-decomposition) with Bayesian priors/posteriors, weights, and evidence |
| `scenarios` | Analysis          | Bull/base/bear scenario assessments, each with probability, description, and trigger conditions                      |
| `meta`      | Analysis          | Pipeline metadata: what would change our mind, edge assessment, models used, processing duration                     |
| `history`   | Markets           | Embed price history directly in the market response                                                                  |
| `analysis`  | Markets           | Embed the latest analysis in a market listing                                                                        |
| `scoring`   | Arbitrage         | Detailed scoring breakdown: spread score, liquidity score, match confidence score, execution score                   |

## Expansion details

### `causal`

Adds a `causal` object with the full [CausalDecomposition](/concepts/causal-decomposition) — 3-7 weighted factors with Bayesian priors, posteriors, evidence, and an aggregation method.

### `scenarios`

Adds a `scenarios` array with typically 3 scenario assessments:

```json theme={null}
{
  "scenarios": [
    {
      "name": "Bull",
      "probability": 0.35,
      "description": "Fed cuts by 25bps, signals further easing",
      "trigger": "CPI continues declining, unemployment ticks up"
    },
    {
      "name": "Base",
      "probability": 0.45,
      "description": "Fed holds rates, dovish language",
      "trigger": "Inflation at target but labor market stable"
    },
    {
      "name": "Bear",
      "probability": 0.20,
      "description": "Fed holds rates, hawkish surprise",
      "trigger": "Inflation rebounds or external shock"
    }
  ]
}
```

### `meta`

Adds an `meta` object with pipeline internals:

```json theme={null}
{
  "meta": {
    "what_would_change_mind": "A surprise inflation reading above 3% or an unexpected geopolitical event",
    "edge_assessment": "Moderate edge driven by inflation trend divergence from market pricing",
    "models_used": ["research", "synthesis", "analysis", "summarization"],
    "duration_ms": 47200
  }
}
```

### `scoring` (arbitrage only)

Adds individual score components to each arbitrage opportunity:

```json theme={null}
{
  "spread_score": 82.5,
  "liquidity_score": 65.0,
  "match_confidence_score": 91.0,
  "execution_score": 70.0
}
```

Weights: spread 40%, liquidity 20%, match confidence 20%, execution 20%.

## Default behavior

Without `?expand=`, expandable fields are omitted from the response. This keeps payloads small for listing and screening use cases. Request only the expansions you need.