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

# Freshness & data quality

> Know what was requested, what was observed and what remains unknown.

## Fresh collection is a timestamp

`observed_at` records when Farelint collected the response. `source_priced_at` records when the source says it priced it, if available. A new collection can still contain a source-cached price. An unknown source pricing time is `null`.

## Empty is not failed

| Result | Interpretation |
| - | - |
| Completed with observations | The source returned parsed fare observations |
| Completed, empty | The source search completed with no offers for those criteria |
| Partial | Some requested scope was observed; inspect source-level gaps |
| Blocked or failed | No conclusion about flight availability can be drawn |

## Preserve uncertainty

Missing taxes, baggage, segments or fare conditions remain explicit. Do not infer direct flights or included bags from a low advertised price. Booking links may expire, and final prices can change.

## Planned error behavior

Invalid input returns a specific validation error. Unavailable sources and exhausted budgets stop dispatch. Rate limits should include retry guidance; clients should back off rather than retry indefinitely. Error responses should carry a request ID, machine-readable code and retryability flag.

## Service targets

Carrier freshness, latency, completion rates and completeness should be measured separately. Targets and any contractual SLA are agreed after validating the actual workload. No global uptime or response-time guarantee is currently offered.


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