Leader Schedule & Block Production
Leaders, slots, and skipped slots. This guide targets Agave 4.1.1 validators, Solana CLI 3.0.10, Anchor 0.32.1, and @solana/kit 7.0.0 clients.
Recipe
Quick-reference recipe card.
solana config set --url devnet
solana balanceimport { createSolanaRpc } from "@solana/kit";
const rpc = createSolanaRpc("https://api.devnet.solana.com");When to reach for this:
- Implementing or debugging leader schedule & block production in production paths
- Teaching the concept to engineers new to Solana
- Auditing whether your stack matches Agave 4.1 era behavior
Working Example
import { createSolanaRpc, address } from "@solana/kit";
const rpc = createSolanaRpc("https://api.devnet.solana.com");
const slot = await rpc.getSlot().send();
const sig = "PASTE_SIGNATURE_AFTER_YOUR_TX";
const tx = await rpc
.getTransaction(sig, { encoding: "json", maxSupportedTransactionVersion: 0 })
.send();
console.log({ slot, err: tx?.meta?.err, cu: tx?.meta?.computeUnitsConsumed });use anchor_lang::prelude::*;
#[program]
pub mod demo {
use super::*;
pub fn log_slot(_ctx: Context<LogSlot>) -> Result<()> {
let clock = Clock::get()?;
msg!("slot: {}", clock.slot);
Ok(())
}
}
#[derive(Accounts)]
pub struct LogSlot {}What this demonstrates:
- RPC access patterns with @solana/kit 7.0.0
- Reading execution metadata (errors, CU) from confirmed transactions
- On-chain sysvar access in Anchor 0.32.1 programs
Deep Dive
How It Works
- Leaders, slots, and skipped slots.
- Solana's account model requires explicit account lists per instruction
- Sealevel executes non-conflicting transactions in parallel
Agave 4.1.1 Notes
- Confirmation semantics follow TowerBFT voting with PoH ordering
- Alpenglow (Votor + Rotor) is rolling out for faster finality - see Consensus section
- Local development: Surfpool 0.12.0 and LiteSVM 0.6.x
Rust Notes
// Use checked math and explicit constraints in programs
require!(amount > 0, MyError::InvalidAmount);Gotchas
- Legacy web3.js v1 snippets - API differs from Kit. Fix: use @solana/kit 7.0.0.
- Wrong cluster - devnet vs mainnet mismatch. Fix: align CLI, RPC, wallet, explorer.
- Float SOL amounts - precision loss. Fix: bigint lamports end-to-end.
- Expired blockhash - dropped txs. Fix: re-fetch blockhash and re-sign.
- Insufficient CU - OOM or budget exceeded. Fix: optimize program + set Compute Budget.
- Missing owner checks - writable account exploits. Fix: Anchor constraints on every mut account.
Alternatives
| Alternative | Use When | Don't Use When |
|---|---|---|
| @solana/kit 7.0.0 | New TypeScript clients | Maintaining legacy code temporarily |
| Solana CLI 3.0.10 | Ops and quick probes | Production transaction signing at scale |
| Surfpool 0.12.0 | Anchor integration tests | Production deployment |
| LiteSVM 0.6.x | Fast unit tests | Full network behavior validation |
FAQs
How does this apply on Agave 4.1.1?
Agave 4.1.1 computes leader slots from stake; only the scheduled leader may produce blocks for those slots.
What Solana CLI version should I use?
Use Solana CLI 3.0.10, which pairs with Agave 4.1.1. Install with agave-install init 4.1.1 (or your team's pin file), then verify with solana --version and agave-install --version.
Should I use @solana/kit or web3.js?
Use @solana/kit 7.0.0 for new TypeScript—typed RPC methods, smaller API surface, and examples on this page already use Kit. Keep web3.js only for legacy codebases; migrate RPC calls and transaction building incrementally.
What commitment level is recommended?
Use confirmed for dashboards and finalized before withdrawals or cross-system callbacks.
How do I debug related failures?
If txs stall near epoch boundaries, fetch getLeaderSchedule and confirm the current leader is online. Skipped slots inflate confirmation time.
Does this work on devnet?
Yes—point CLI and RPC to https://api.devnet.solana.com. Behavior matches mainnet; only account data and economics differ.
How do compute units affect this?
Leader changes do not alter program CU, but congestion spikes often follow popular leader slots—budget extra priority fee.
What is the Anchor 0.32.1 pattern?
Anchor 0.32.1 uses #[program], Context<T>, and #[derive(Accounts)] with explicit mut/signer constraints—run anchor build and anchor test on 0.32.1 via avm use 0.32.1.
How do I test with Surfpool 0.12.0?
Start Surfpool 0.12.0, point RPC to its port, and run anchor test or client integration scripts against forked accounts.
Can LiteSVM 0.6.x cover this?
LiteSVM does not rotate leaders; you are always the only producer.
What changed in the Agave era?
The validator client rebranded to Agave (4.1.1), CLI 3.0.10 aligns with it, and Alpenglow work is changing finality—pin versions and read release notes each upgrade.
Where do I find related RPC methods?
getLeaderSchedule, getSlot, getBlockProduction, and getEpochInfo track who should be producing now.
Related
- Browse other pages in the
core-architecture-componentssection for complementary topics - Solana Basics - account and transaction orientation
Stack versions: This page was written for Agave 4.1.1, Solana CLI 3.0.10, Anchor 0.32.1, anchor-lang 0.32.1, Rust 1.91.1, @solana/kit 7.0.0, Surfpool 0.12.0, and LiteSVM 0.6.x.