Learn Hardcore Indonesian: Kami setuju bahwa tujuan rapat harus jelas. - We agree that the purpose of the meeting must be clear.

In the sentence, kami implies the speaker’s group agrees, but the person addressed is not included. If you want to include the listener, use kita: Kita setuju bahwa tujuan rapat harus jelas.

Do I have to use bahwa here, or can I drop it?

bahwa corresponds to “that” introducing a content clause and is perfectly correct.
In everyday speech, it’s common (and natural) to omit bahwa: Kami setuju tujuan rapat harus jelas.
Keep bahwa if the clause is long or complex, because it improves clarity and formality.
Very formal writing may also use bahwasanya, but that’s literary/archaic.

Should it be setuju dengan? When do I use setuju, setuju dengan, and menyetujui?

setuju (intransitive) = “to agree.” Use it with a clause (often with/without bahwa): Kami setuju (bahwa) …
setuju dengan + noun/pronoun = “agree with [someone/something]”: Kami setuju dengan Anda. / Saya setuju dengan usulan itu.
menyetujui + noun (transitive) = “to approve [something]” (often an authority/official sense): Pimpinan menyetujui rencana itu. Tip: If what follows is a clause, use setuju (bahwa). If it’s a person/thing, use setuju dengan. If you’re approving a proposal/document, use menyetujui.

Can I use sepakat instead of setuju? What about menyepakati?

sepakat ≈ synonym of setuju, a touch more formal or collaborative: Kami sepakat bahwa tujuan rapat harus jelas.
menyepakati + noun = “to agree upon [something]” together: Kedua pihak menyepakati tujuan rapat.
Nouns: persetujuan (approval), kesepakatan (agreement/accord).

How does tujuan rapat work? Could I say tujuan dari rapat?

Indonesian puts the head noun first, then the modifier: tujuan rapat = “meeting’s objective/objective of the meeting.”
tujuan dari rapat is also acceptable but more wordy; dari is often unnecessary in simple noun–noun compounds.
Compare:
- tujuan rapat (natural, concise)
- tujuan dari rapat (more explicit, slightly heavier)

Is rapat the same as “meeting”? How is it different from pertemuan?

rapat = a formal/organizational meeting (work, committee, board).
pertemuan = a meeting in a broader sense (a get-together, encounter, session). You could say tujuan rapat for a work meeting, but tujuan pertemuan for a general meeting.

What nuance does harus have? How does it compare to perlu, wajib, mesti, and sebaiknya?

harus = must/obligatory (strong necessity): harus jelas.
wajib = obligatory/mandatory (often official/legal).
perlu = need/necessary (weaker than “must”).
mesti = must/have to (colloquial/regional, similar to harus).
sebaiknya = should/it’s advisable (recommendation). Choose based on strength/formality: wajib (formal/official) > harus/mesti > perlu > sebaiknya.

Is jelas an adjective here? When would I use dengan jelas, menjelaskan, or memperjelas?

Here jelas is a predicate adjective describing tujuan rapat: it “must be clear.”
dengan jelas = “clearly” (adverb): Tujuan rapat harus disampaikan dengan jelas.
menjelaskan = “to explain [something]”: Tolong jelaskan tujuan rapat.
memperjelas = “to make clearer/clarify”: Contoh ini memperjelas tujuan rapat.
Noun: kejelasan = clarity: Kejelasan tujuan rapat itu penting.

Can I drop the subject and just say Setuju? Also, when do I use setuju untuk + verb vs setuju bahwa + clause?

In conversation, Setuju! = “Agreed!” is common as a standalone response.
You can omit bahwa but normally keep the subject: (Kami) setuju tujuan rapat harus jelas.
Use:
- setuju untuk + verb when agreeing to do something: Kami setuju untuk memperjelas tujuan rapat.
- setuju bahwa + clause when agreeing with a statement: Kami setuju bahwa tujuan rapat harus jelas.

How do I make it negative or soften it? And what about “must not”?

Negative of “agree”: tidak setuju = disagree: Kami tidak setuju bahwa …
Softer/polite hedge: kurang setuju = “not quite agree”: Kami kurang setuju bahwa …
Be careful with modality:
- tidak harus = “not necessary/doesn’t have to”: Tujuan rapat tidak harus jelas.
- “must not” is usually tidak boleh (“not allowed to”), not harus tidak. For example: Tujuan rapat tidak boleh ambigu (“must not be ambiguous”).
- To forbid clarifying, you’d say something like Tujuan rapat tidak boleh dijelaskan (context-dependent).

Do I need a comma before bahwa?

No. Indonesian normally does not place a comma before bahwa. Your sentence is correctly punctuated without a comma.

Can I use kalau instead of bahwa here?

No. kalau means “if/when.” In colloquial speech you might hear dia bilang kalau … after verbs like bilang/katanya, but with setuju you should use bahwa (or omit it in casual speech). So: Kami setuju (bahwa) …, not Kami setuju kalau …

Can I add -nya for definiteness, like tujuannya harus jelas?

Yes:

Tujuannya harus jelas. = “The purpose must be clear” (definite/known in context).
With the full phrase: Tujuan rapatnya harus jelas. = “The meeting’s purpose must be clear,” stressing that particular meeting. Use -nya when the referent is specific/known to both speaker and listener.

How would I say “The meeting’s purpose must be clarified/made clear”?

Tujuan rapat harus diperjelas. (must be clarified)
Tujuan rapat harus dijelaskan dengan jelas. (must be explained clearly)
Tujuan rapat harus dibuat jelas. (understandable, but less idiomatic than diperjelas) These focus on the action of making it clear, rather than simply stating it “must be clear.”

What are some register alternatives (more formal vs more casual)?

Formal:
- Kami sepakat bahwa tujuan rapat harus jelas.
- Kami berpendapat bahwa tujuan rapat harus jelas. (we are of the opinion that…)
Neutral:
- Kami setuju bahwa tujuan rapat harus jelas.
Casual:
- Kita setuju tujuan rapat harus jelas, ya?
- Setuju kok, tujuan rapat harus jelas.

Is there any difference between tujuan rapat and agenda rapat?

Yes:

tujuan rapat = the objective/purpose (why the meeting is held).
agenda rapat = the list of items/topics to be discussed. You can have a clear agenda but a vague purpose—and vice versa.