No quiero firmar el contrato hasta que esté revisado.

Because after hasta que, Spanish normally uses the subjunctive when the action is still in the future or has not happened yet from the speaker’s point of view.

Here, the speaker is saying they do not want to sign the contract until it has been reviewed. At the time of speaking, that review is still pending, so Spanish uses esté.

• hasta que esté revisado = until it is reviewed / until it has been reviewed
• hasta que está revisado would sound wrong here

This is a very common pattern:

• Esperaré hasta que llegue.
• No salgas hasta que termine.

Hasta que means until.

It introduces the point in time when something will finally happen or become true. In this sentence:

• No quiero firmar el contrato hasta que esté revisado.

the idea is:

• I do not want to sign the contract before the review is complete.
• I only want to sign it once it is in a reviewed state.

A useful rule:

• hasta que + subjunctive when the action is still pending or future
• hasta que + indicative when talking about something habitual or already completed in the past, depending on context

For example:

• Espera hasta que venga. = Wait until he comes.
• Esperé hasta que vino. = I waited until he came.

Because the subject is the same person in both parts.

• No quiero firmar... = I do not want to sign
  • The person who wants and the person who signs are both I

Spanish normally uses:

• querer + infinitive when the subject stays the same

So:

• Quiero firmar el contrato. = I want to sign the contract.

But if the subject changes, Spanish usually uses:

• querer que + subjunctive

For example:

• Quiero que él firme el contrato. = I want him to sign the contract.

Because estar + past participle often describes the resulting state of something, while ser + past participle focuses more on the action itself.

Here, the important idea is that the contract should be in the state of already reviewed before signing.

• esté revisado = be reviewed / be in a reviewed state
• sea revisado = be reviewed, with more focus on the process or event

So this sentence is about the condition that must be met before signing:

• the contract must already be reviewed

That is why estar sounds natural here.

It is originally a past participle of the verb revisar, but here it works very much like an adjective after estar.

So in:

• esté revisado

revisado describes the state of the contract, just like an adjective would.

This is very common in Spanish:

• La puerta está cerrada.
• El informe está terminado.
• La comida está preparada.

In all of these, the participle describes the condition or result.

Because revisado agrees with el contrato, which is masculine singular.

In Spanish, participles used adjectivally agree in gender and number with the noun they describe.

• el contrato → revisado
• la carta → revisada
• los contratos → revisados
• las cartas → revisadas

So:

• No quiero firmar la carta hasta que esté revisada.
• No quiero firmar el contrato hasta que esté revisado.

Yes, and it is a very natural alternative.

• hasta que esté revisado focuses on the resulting state: the contract must already be reviewed
• hasta que se revise focuses more on the action of reviewing happening

So these are both possible:

• No quiero firmar el contrato hasta que esté revisado.
• No quiero firmar el contrato hasta que se revise.

The difference is small, but this is a useful way to think about it:

• esté revisado = until it is in reviewed condition
• se revise = until it gets reviewed

Both are correct. The original sentence sounds slightly more focused on the finished condition of the contract.

Because Spanish often omits subject pronouns when they are not needed.

The verb form quiero already tells you the subject is yo. So:

• No quiero firmar... already means
• I don’t want to sign...

Including yo is possible, but it usually adds emphasis, contrast, or clarity:

• Yo no quiero firmar el contrato... = I don’t want to sign the contract...

In neutral Spanish, leaving out yo is completely normal.

The accent mark is necessary because esté is a verb form of estar in the present subjunctive.

• esté = that I/he/she/it be
• este without an accent is usually a demonstrative word like this

So the accent helps distinguish them:

• Quiero que esté listo. = I want it to be ready.
• este contrato = this contract

It is not optional here; the correct spelling is esté.

It is general Spanish and sounds natural in Spain as well as in most other Spanish-speaking places.

Nothing in the sentence is uniquely Spain-specific. A speaker from Spain would understand and use it naturally, and so would speakers in Latin America.

So if you learn this sentence as it is, you can use it widely:

• No quiero firmar el contrato hasta que esté revisado.

It is standard, neutral Spanish.