Instructions Best Practices

Small, validated, single-purpose handlers scale better than god-instructions.

How to Use This List

Review each handler for single responsibility.
Ensure errors are typed and documented in IDL.
Profile CU on hot paths before mainnet.

A - Handler design

One clear action per instruction avoid multi-mode opcodes.
Validate args with require! early before CPIs or transfers.
Delegate complex logic to modules keep #[program] thin.
Emit events for state changes clients should not parse logs by hand.

B - Accounts and CPIs

Validate CPI programs in accounts struct not inside unchecked metas.
Use ctx.bumps for PDA CPI signers do not re-derive bumps.
Document remaining_accounts order in IDL docs or constants.
Prefer explicit accounts over args for pubkeys that must sign.

FAQs

What Anchor version is assumed?

0.32.1 throughout this section.

Can a PDA be a Signer in accounts struct?

No. Use seeds constraints and CPI signing.

Where is bump stored?

In your account struct field, set at initialization.

How do clients derive PDAs?

Use @solana/kit 7.0.0 with matching seed bytes.

What program id is used for PDAs?

Your Anchor program's declare_id address.

Do seeds include bump?

Not in seeds array; bump is separate parameter to find_program_address.

How to debug PDA failures?

Compare logged keys; verify seeds and program id client-side.

Are PDAs rent-exempt?

Yes when holding data; fund with payer on init.

Can one PDA sign multiple CPIs in one ix?

Yes with same signer seeds for each CPI.

Instructions Best Practices

Small, validated, single-purpose handlers scale better than god-instructions.

How to Use This List

Review each handler for single responsibility.
Ensure errors are typed and documented in IDL.
Profile CU on hot paths before mainnet.

A - Handler design

One clear action per instruction avoid multi-mode opcodes.
Validate args with require! early before CPIs or transfers.
Delegate complex logic to modules keep #[program] thin.
Emit events for state changes clients should not parse logs by hand.

B - Accounts and CPIs

Validate CPI programs in accounts struct not inside unchecked metas.
Use ctx.bumps for PDA CPI signers do not re-derive bumps.
Document remaining_accounts order in IDL docs or constants.
Prefer explicit accounts over args for pubkeys that must sign.

FAQs

What Anchor version is assumed?

0.32.1 throughout this section.

Can a PDA be a Signer in accounts struct?

No. Use seeds constraints and CPI signing.

Where is bump stored?

In your account struct field, set at initialization.

How do clients derive PDAs?

Use @solana/kit 7.0.0 with matching seed bytes.

What program id is used for PDAs?

Your Anchor program's declare_id address.

Do seeds include bump?

Not in seeds array; bump is separate parameter to find_program_address.

How to debug PDA failures?

Compare logged keys; verify seeds and program id client-side.

Are PDAs rent-exempt?

Yes when holding data; fund with payer on init.

Can one PDA sign multiple CPIs in one ix?

Yes with same signer seeds for each CPI.

Instructions Best Practices

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Instructions Best Practices