Etydhv

Well pretty much the title says it all, I am Bulgarian native speaker and we have way of saying this which literally translated is "clean coin".

For instance: "I am taking his words as a clean coin." (but this is really translated literally so I expect to mean gibberish in English)

Context in which I would like to use this idiom:
"We've been working together for quite some time now and I never saw him make a mistake, henceforth I am taking his bugs ______."

no questions asked

An expression indicating that one will not be questioned or hassled
about something, typically as an incentive for sharing some
information or doing something that otherwise may be the subject of
suspicion, further inquiry, or punishment.

From Farlex Dictionary of Idioms

Should fit into your context with the inclusion of a comma;

"We've been working together for quite some time now and I never saw him make a mistake, henceforth I am taking his bugs, no questions asked."

I'm taking his bugs as fact.

Just adding to the list. [I wish I could agree with myself.]

In the case of the bugs, I assume it'a situation where he says something like, "these are the problems I've found". You might answer, "ok, I'll take those findings on trust and won't double check."

Free dictionary definition:

take (something) on trust

To believe something implicitly, without requiring that someone
provide proof or evidence.
I took their explanation on trust, as
they've never given me reason before to disbelieve what they've told
me.
He wants us to take it on trust that he'll pay us back, but he
already owes us a substantial amount of money.

If it were directly his words you meant, you could say "I take his word for it". Or: "I'm taking him at his word."

[*Assuming your question was asked in good faith, it's not such a good idea to say what I did originally: "I'll take those bugs on trust and won't double check"...
and there's another sample answer: I'm traumatised and not going to take any more questions in good faith. It's usually used when you take something on trust with bad consequences.]

As in:

"We've been working together for quite some time now and I never saw him make a mistake, henceforth I am taking his bugs whole schmear."

the whole schmear TFD an idiom

every aspect of something

We don't say it quite like Bulgarian. Instead in English we "take his word for it", as in: "I am taking his word for it". The idiom can be expanded to include "at face value", as in "to take his word at face value".

ie: I said to my friend, "the American told me that in the United States you should tip the waiter after paying the bill". My friend replied, but we don't usually tip in Bulgaria, why should I tip in the United States?". I replied, "I don't know, but I am taking his word for it".

In the above situation, the first person is inclined to believe the American and has taken his statement (words) "at face value", even though the friend "has his doubts". Cascabel refers to "...Good as Gold" which is a contraction of the saying: "his word is good as gold", which implies expertise in the field.

Another common expression is:

take (someone or something) for granted

To consider something as being innately or unfailingly true, correct, real, or available,
as in:

• I guess I just took your support for granted, because I thought you would be there for me no matter what.

(The Free Dictionary)