---
title: "What is an evidence status?"
description: "An evidence status labels every recall response: supported, conflicted, or no known support. The four status values and what agents do with each."
canonical: https://past.dev/glossary/evidence-status
last-updated: 2026-09-02
---
# Evidence status

Source: https://past.dev/glossary/evidence-status

An evidence status is an explicit label on a recall response stating whether the evidence supports an answer, conflicts, or is absent. It turns retrieval from a ranked list into a claim the caller can act on. Without a status, an empty result is ambiguous and a weak match looks like an answer. With one, the agent can branch: answer, surface the conflict, ask the user, or retry later.

## The problem a status solves

Raw retrieval returns a ranked list and nothing else. The list does not say whether the top result answers the question, whether other stored records contradict it, or whether an empty list means absence or failure. Similarity scores do not help: they are relative to the candidate pool and make no claim about truth. An evidence status adds that claim as a machine-readable field, so the agent can branch on it instead of inferring quality from rank.

## The four status values in past.dev

The recall API of [past.dev](/docs/memory-api/quickstart) reports one of four status values on every response, which makes a concrete worked example of the concept:

| Status value | Meaning | What the agent does |
| --- | --- | --- |
| `Supported` | The returned evidence establishes the answer. | Use it and cite the evidence. |
| `Conflicted` | Credible sources disagree; evidence from both sides is returned. | Present both sides with dates. See [contradictory facts](/guides/contradictory-facts). |
| `NoKnownSupport` | The stored evidence does not establish an answer. | Abstain: ask the user, escalate, or search elsewhere. |
| `UnknownBecauseDegraded` | Retrieval could not complete. | Treat as unknown and retry. Absence was never established. |

## Why it matters for AI agents

An explicit status turns recall into a branch point the agent can code against: answer, surface a conflict, abstain, or retry. Two distinctions matter most. Absence is different from failure: a store with no answer and a lookup that broke both return nothing, and only the status keeps them apart. A conflict is information: credible sources disagreeing, each with dates, is a state to surface rather than resolve silently. The status plus the dated evidence also records why the agent acted as it did, the raw material of an [audit trail](/glossary/audit-trail).

How status reporting and abstention are evaluated is described in the [benchmark methodology](/benchmarks/methodology).

## Related concepts

- **[Abstention](/glossary/abstention)**: the behavior a no-support status triggers.
- **[Grounding](/glossary/grounding)**: the evidence link a supported status certifies.
- **[Recall](/glossary/recall)**: the operation the status is attached to.
- **[Audit trail](/glossary/audit-trail)**: where statuses and evidence end up when actions must be explained.

## Frequently asked questions

### What is an evidence status in AI memory?

It is an explicit label on a recall response saying what the returned evidence establishes: it supports an answer, sources conflict, or no stored evidence answers the question. The agent branches on it.

### Why is an empty search result ambiguous?

An empty list can mean the fact was never stored, the query missed it, or retrieval failed partway. Those three cases call for different actions, and a status value tells them apart.

### What status values does past.dev return?

Supported, Conflicted, NoKnownSupport, and UnknownBecauseDegraded. Supported evidence establishes the answer, Conflicted returns both sides of a disagreement, NoKnownSupport reports that stored evidence does not answer, and UnknownBecauseDegraded means retrieval could not complete.

## Related

- [Abstention](https://past.dev/glossary/abstention)
- [Grounding](https://past.dev/glossary/grounding)
- [Recall](https://past.dev/glossary/recall)
- [Contradictory facts](https://past.dev/guides/contradictory-facts)
- [Memory API quickstart](https://past.dev/docs/memory-api/quickstart)