A teacher who claims to be awakened
The canon's tests for a teacher are about conduct, not claims. A person's ethics, it says, show only to someone who lives with them for a long time and pays attention, and their wisdom shows in discussion. The Buddha told monks to scrutinize even him, by checking what could be seen and heard of his conduct for any sign of corruption. The suttas also list pride in a meditative attainment among the marks of a person of poor character, and say the good person does not use even a real attainment to put others down. None of this proves or disproves any particular claim, and nothing here will. It does suggest what to watch, and for how long, before trusting, and it never asks you to stay close to someone whose conduct is doing harm.
What the suttas say
don’t go by oral transmission, don’t go by lineage, don’t go by testament, don’t go by canonical authority, don’t rely on logic, don’t rely on inference, don’t go by reasoned train of thought, don’t go by the acceptance of a view after deliberation, don’t go by the appearance of competence, and don’t think “The ascetic is our respected teacher.” But when you know for yourselves:
The Kālāma discourse — the canon's charter for testing teachings.
Where this stops: It is not permission to believe whatever one likes; it ends with what the wise praise. Never a reason to stay with a teacher who is doing harm.
AN 3.65:25.3–25.4 · With the Kālāmas of Kesamutta
Mā anussavena, mā paramparāya, mā itikirāya, mā piṭakasampadānena, mā takkahetu, mā nayahetu, mā ākāraparivitakkena, mā diṭṭhinijjhānakkhantiyā, mā bhabbarūpatāya, mā samaṇo no garūti. Yadā tumhe kālāmā attanāva jāneyyātha:
Soṇa, there are ascetics and brahmins who—based on form, which is impermanent, suffering, and perishable—regard themselves thus: ‘I’m better’, or ‘I’m equal’, or ‘I’m worse’. What is that but a failure to see truly?
Told to the householder Soṇa — ranking oneself better, equal, or worse is one mistake, not three, which includes the person who always comes out worse.
Where this stops: About measuring a self built on the aggregates; it does not say that differences of skill or circumstance are unreal.
SN 22.49:2.1–2.4 · With Soṇa
Ye hi keci, soṇa, samaṇā vā brāhmaṇā vā aniccena rūpena dukkhena vipariṇāmadhammena ‘seyyohamasmī’ti vā samanupassanti; ‘sadisohamasmī’ti vā samanupassanti; ‘hīnohamasmī’ti vā samanupassanti; kimaññatra yathābhūtassa adassanā?
Mendicants, a mendicant who is an inquirer, unable to encompass another’s mind, should scrutinize the Realized One for two things—things that can be seen and heard: ‘Can anything corrupt be seen or heard in the Realized One or not?’ Scrutinizing him they find that nothing corrupt can be seen or heard in the Realized One.
The Buddha's own instructions for scrutinizing a teacher, including himself.
Where this stops: Never a reason to stay with a teacher who is doing harm.
MN 47:4.1–4.4 · The Inquirer
Vīmaṁsakena, bhikkhave, bhikkhunā parassa cetopariyāyaṁ ajānantena dvīsu dhammesu tathāgato samannesitabbo cakkhusotaviññeyyesu dhammesu: ‘ye saṅkiliṭṭhā cakkhusotaviññeyyā dhammā, saṁvijjanti vā te tathāgatassa no vā’ti? Tamenaṁ samannesamāno evaṁ jānāti: ‘ye saṅkiliṭṭhā cakkhusotaviññeyyā dhammā, na te tathāgatassa saṁvijjantī’ti.
Mendicants, these four things can be known in four situations. What four? You can get to know a person’s ethics by living with them. But only after a long time, not casually; only when attentive, not when inattentive; and only by the wise, not the witless. You can get to know a person’s purity by dealing with them. … You can get to know a person’s resilience in times of trouble. … You can get to know a person’s wisdom by discussion. But only after a long time, not casually; only when attentive, not when inattentive; and only by the wise, not the witless.
How a person is actually known — over a long time, with attention, from close up — a standard that applies to a teacher as much as to anyone.
Where this stops: It counsels patience before trusting and before condemning; it is not a reason to stay close to someone already known to be doing harm.
AN 4.192:1.1–1.6 · Facts
Cattārimāni, bhikkhave, ṭhānāni catūhi ṭhānehi veditabbāni. Katamāni cattāri? Saṁvāsena, bhikkhave, sīlaṁ veditabbaṁ, tañca kho dīghena addhunā, na ittaraṁ; manasikarotā, no amanasikarotā; paññavatā, no duppaññena. Saṁvohārena, bhikkhave, soceyyaṁ veditabbaṁ, tañca kho dīghena addhunā, na ittaraṁ; manasikarotā, no amanasikarotā; paññavatā, no duppaññena. Āpadāsu, bhikkhave, thāmo veditabbo, so ca kho dīghena addhunā, na ittaraṁ; manasikarotā, no amanasikarotā; paññavatā, no duppaññena. Sākacchāya, bhikkhave, paññā veditabbā, sā ca kho dīghena addhunā, na ittaraṁ; manasikarotā, no amanasikarotā; paññavatā, no duppaññenāti.
Furthermore, take an untrue person who, quite secluded from sensual pleasures, secluded from unskillful qualities, enters and remains in the first absorption, which has the rapture and bliss born of seclusion, while placing the mind and keeping it connected. They reflect: ‘I have attained the first absorption, unlike these other mendicants.’ And they glorify themselves and put others down on account of that. This too is a quality of an untrue person. A true person reflects: ‘The Buddha has spoken of not being determined even by the attainment of the first absorption. For however they imagine it, it turns out to be something else.’ Keeping to themselves the fact that they are not determined by that, they don’t glorify themselves and put others down on account of their attainment of the first absorption. This too is a quality of a true person.
Even a real meditative attainment appears in the list of things one can be proud of — the canon's own case of spiritual pride.
Where this stops: The sutta does not ask anyone to doubt or disown a real experience, only not to use it to put others down; questions about attainments belong with a teacher.
MN 113:21.1–21.10 · A True Person
Puna caparaṁ, bhikkhave, asappuriso vivicceva kāmehi vivicca akusalehi dhammehi savitakkaṁ savicāraṁ vivekajaṁ pītisukhaṁ paṭhamaṁ jhānaṁ upasampajja viharati. So iti paṭisañcikkhati: ‘ahaṁ khomhi paṭhamajjhānasamāpattiyā lābhī, ime panaññe bhikkhū paṭhamajjhānasamāpattiyā na lābhino’ti. So tāya paṭhamajjhānasamāpattiyā attānukkaṁseti, paraṁ vambheti. Ayampi, bhikkhave, asappurisadhammo. Sappuriso ca kho, bhikkhave, iti paṭisañcikkhati: ‘paṭhamajjhānasamāpattiyāpi kho atammayatā vuttā bhagavatā. Yena yena hi maññanti tato taṁ hoti aññathā’ti. So atammayataññeva antaraṁ karitvā tāya paṭhamajjhānasamāpattiyā nevattānukkaṁseti, na paraṁ vambheti. Ayampi, bhikkhave, sappurisadhammo.