Matsya Purana — Catalogue of the Eighteen Puranas
यत् तद् ईशानकं कल्पं वृत्तान्तमधिकृत्य च वसिष्ठायाग्निना प्रोक्तम् आग्नेयं तत्प्रचक्षते //
yat tad īśānakaṃ kalpaṃ vṛttāntamadhikṛtya ca vasiṣṭhāyāgninā proktam āgneyaṃ tatpracakṣate //
That account which concerns the Īśānaka Kalpa—spoken by Agni to Vasiṣṭha—is therefore declared to be the Agneya tradition, that which is related to Agni.
Indirectly, it situates the narrative within a specific Kalpa framework (Īśānaka Kalpa), implying a structured cosmic cycle in which creation/dissolution accounts are organized and transmitted.
It does not prescribe duties directly; rather, it establishes textual authority and lineage of teaching (Agni → Vasiṣṭha), a common Purāṇic method used to validate later dharma instructions for kings and householders.
No specific Vāstu or iconographic rule is stated; the key ritual-literary significance is the naming of the tradition as “Agneya,” grounding the account in Agni’s authoritative transmission.