This āgama is a technical component in the ancient vyāvahāra-śāstra (vyavahara-sastra) or discourses of legal and judicial matters. The documents or legal papers containing proofs, signature of the witness etc. , are also called āgama. In Yājñavalka-smṛti (Yajnavalka-smriti) it is said, if there is no written āgama (documentation) on the things inherited, the heir’s ownership on those articles is not determined properly —

na hi āgamarahitād bhogād bhogye

bhoktuḥ svamitvaṁ śakyaṁ niścetum.

  • This is written by the famous annotator Aparārka (Apararka) , while the original śloka of Yājñavalka (Yajnavalka)was —

āgamotyadhiko bhogat vinā purvakramagatat

āgamepi valaṁ naiva bhuktiḥ stokāpi yatra no. 

In the annotation of this śloka (sloka; verse), Aparārka cites Nārada (Narada), and raises a point that, even if the documentation is ready and the witnesses are alive, the enjoyment of inherited property, if not immovable, is not very certain. It needs to be noted whether in the interval period, the property has been sold or donated. In all these matters, the final āgama (agama) is necessary and that āgama has to be viśuddha (visudha; pure). It is because of a viśuddha āgama that the inherited property becomes worthy of enjoyment, as Nārada says —

vidyamāne’pi likhite jīvatsvapi sākṣiṣuḥ

viśeṣataḥ sthāvarāṇāṁ yatrabhuktaṁ na tatsthiraṁ 

āgamena viśuddhena bhogo yāti pramāṇtāṁ

aviśuddhāgamo bhogaḥ prāmāṇyaṁ nādhigacchati.

So, the enjoyment of inherited property,  is certified only on the basis of a proof-ridden and ‘pure’ āgama. Manu says —

Where there is enjoyment of property, but no written documentation or ‘āgama’ can be found, it has to be taken for granted that āgama itself is the condition of enjoyment, and only enjoyment does not certify the ownership of property —

sambhoga yatra dṛśyeta  na dṛśyetāgamaḥ kvacit

āgamaḥ kāraṇaṁ tatra na sambhoga iti sthitiḥ .

Mahābhārata (Mahabharata) says the same in a generalised way. It says — in the context of laukika (popular) dharma and practices, āgama has been founded in order to remain within the limits of such lokadharma, and it is good to follow the proof of āgama in such cases. Mahādeva(Mahadeva) says that there are śāstras that control the human ethics and practices. And the proof of their validity is the fact that those who follow these, are seen to be determined in the path of dharma

āgamaḥ lokadharmāṇāṁ maryādā sarvanirmitāḥ

prāmāṇyenānuvartante dṛśyante ca dṛḍhavrata. 

Here in fact the scriptural sense of āgama-prāmāṇya (agama-pramanya) and the legal sense of āgama as proof have been one and the same.