Tools / Memory

assert_fact()

Key

Writes a temporal fact. The server sets available_at = now unless an audited backdate_reason is supplied — so the system always knows when it could have known something. Hash-based duplicate detection.

assert_fact(entity, attribute, value, valid_from, backdate_reason)→ FACT

Callable over MCP as assert_fact(entity, attribute, value, valid_from, backdate_reason). REST mirror POST /v1/facts Planned — alpha is MCP-only

Why your agent calls it

For the ground-truth layer: things that are simply true, with the moment they became knowable recorded honestly. Because the server stamps available_at itself, no later analysis can pretend it knew this earlier than it did.

What it returns

assert_fact() · Write a temporal fact with an honest available_at.ILLUSTRATIVE

Call it from an agent

Over MCP, your agent invokes it on its own when the moment calls for it — just describe the situation. A Python SDK for headless runtimes is planned; this is what the call will look like.

agent · python sdkSDK · PLANNED — ALPHA IS MCP-ONLY

from cascadian import Cascadian

cx = Cascadian(api_key=os.environ["CASCADIAN_API_KEY"])

result = cx.assert_fact(
    entity="discount_tier",
    attribute="status",
    value="live",
    valid_from="2025-09-01",
    backdate_reason="imported from CRM export",
)

Parameters

Param	Type	Description
entityREQUIRED	string	The entity the fact is about.
attributeREQUIRED	string	The attribute being asserted.
valueREQUIRED	string	The value of the attribute.
valid_from	timestamp	When the fact became true in the world.
backdate_reason	string	Audited reason to set available_at in the past.

Example response

assert_fact()JSON · ILLUSTRATIVE

{
  "fact_id": "fct_2231",
  "entity": "discount_tier", "attribute": "status", "value": "live",
  "valid_from": "2025-09-01",
  "available_at": "2026-06-11T17:02:11Z",
  "deduped": false
}

Related — Memory

keybootstrap()The ~200-token session card your agent reads first.keyingest_source()Store a raw source — chunked, embedded, indexed.keypropose_memory()Propose a memory item — contradiction-checked on write.keylink_memories()A typed relationship edge, with rationale.keysupersede_memory()Revise without erasing — new row, old row closed.keysearch_memory()Hybrid retrieval with an honest empty result.keyget_facts()What was true, as of any moment.keyget_entity()The versioned dossier for one entity.keyget_memory()The full evidence card, by id.keyget_context_pack()Everything knowable for a decision, stamped and typed.keylist_contradictions()Open conflicts waiting on a human.