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

# Why

> GET /v1/memories/{id}/why. The evidence chain of one block as of a point in time, in the order it was said.

Walks causal, argumentative, and temporal edges out of one block and names each neighbour's role. Only edges and nodes known at `as_of` are used, so the chain grows as `as_of` moves forward.

## Parameters

<ParamField path="id" type="string" required />

<ParamField query="as_of" type="timestamp or date" required />

<ParamField query="valid_at" type="timestamp" />

<ParamField query="depth" type="integer" default="3" />

## Response

<ResponseField name="chain" type="Link[]">
  Ordered by `asserted_at`. Each link: `node` (NodeRow), `depth`, `path`, `via` (edge type), `role`.
  Roles follow the edge type and direction: `subject`; `cause` / `effect`; `contributing_cause` / `contributed_effect`; `trigger` / `triggered`; `preventer` / `prevented`; `support` / `supported`; `contradiction` / `contradicted`; `qualification` / `qualified`; `successor` / `predecessor`; `restatement` / `restated`; `concurrent`.
</ResponseField>

<ResponseField name="reason" type="string">
  Only when `chain` is empty: `not_yet` or `absent`.
</ResponseField>

<ResponseField name="certificate" type="object" />

<CodeGroup>
  ```bash Request theme={null}
  curl -s "$TCKG/v1/memories/up/why?as_of=2024-10-01"
  ```

  ```json Response theme={null}
  {"chain": [
     {"node": {"id": "capex", "statement": "hyperscaler AI capex keeps rising", "...": "..."},
      "depth": 1, "path": ["up", "capex"], "via": "CAUSES", "role": "cause"},
     {"node": {"id": "up", "statement": "NVDA goes up", "...": "..."},
      "depth": 0, "path": ["up"], "via": null, "role": "subject"},
     {"node": {"id": "down", "statement": "NVDA goes down", "...": "..."},
      "depth": 1, "path": ["up", "down"], "via": "SUPERSEDES", "role": "successor"}],
   "certificate": {"as_of": "2024-10-01T23:59:59.999999+00:00", "tx_as_of": "...", "backfill": {"batches": 2, "rows": 5}}}
  ```
</CodeGroup>

Asked as of June 2024, the same call returns only `capex` and `up`: the reversal was not known yet.


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.