Compressed PDA Programs

Build Solana programs with compressed accounts via CPI to the Light System Program. No rent-exemption required.

Creation cost	Solana account	Compressed account
PDA (128 bytes)	~1,100,000 lamports	~5,000 lamports

When to use compressed PDAs

• Per-user state (profiles, game state, credentials)
• DePIN device registrations
• Nullifier-based double-spend prevention
• Infrequently accessed accounts

Choosing approach

Criteria	Light-PDA (easy)	Compressed PDA (advanced)
When	Rent-free version of existing Anchor accounts	Custom compressed state with ZK proofs
Skill	light-sdk (Anchor macro pattern)	This skill (solana-compression)
Macro	#[light_account(init)]	LightAccount::new_init() manual CPI
Dependencies	light-sdk, light-compressible	light-sdk, light-sdk-types

If you just want rent-free Anchor accounts, use the light-sdk skill instead. This skill is for programs that require manual CPI to the Light System Program (custom compressed state, ZK proofs, address derivation).

Client-program interaction flow

 ├─ Client
 │  ├─ Get ValidityProof from RPC.
 │  ├─ pack accounts with PackedAccounts into PackedAddressTreeInfo and PackedStateTreeInfo.
 │  ├─ pack CompressedAccountMeta.
 │  ├─ Build Instruction from PackedAccounts and CompressedAccountMetas.
 │  └─ Send transaction.
 │
 └─ Custom Program
    ├─ CpiAccounts parse accounts consistent with PackedAccounts.
    ├─ LightAccount instantiates from CompressedAccountMeta.
    │
    └─ Light System Program CPI
       ├─ Verify ValidityProof.
       ├─ Update State Merkle tree.
       ├─ Update Address Merkle tree.
       └─ Complete atomic state transition.

Domain references

Topic	Reference
Program operations (create, update, close, burn, reinit)	references/compressed-pdas.md
Client SDK (TypeScript + Rust)	references/client.md
Nullifier PDAs (double-spend prevention)	references/nullifier-pdas.md
Error codes (6000-16034)	references/error-codes.md

Reference repos

Basic operations — create, update, close, reinit, burn (each with Anchor and Native variants)

Counter — full lifecycle (create, increment, decrement, reset, close): - counter/anchor — Anchor with Rust and TypeScript tests - counter/native — Native with light-sdk and Rust tests - counter/pinocchio — Pinocchio with light-sdk-pinocchio and Rust tests

Other examples: - create-and-update — Create and update with a single validity proof in one instruction - read-only — Create and read a compressed account onchain - account-comparison — Compressed vs regular Solana accounts

Nullifier: - nullifier-program — Rent-free PDA for duplicate execution prevention. SDK: light-nullifier-program | example client

Airdrop claim: - simple-claim — Compressed tokens decompressed to SPL on claim with cliff - merkle-distributor — SPL tokens with compressed PDA claim tracking, linear vesting, partial claims, clawback - example-token-distribution — Simple client-side distribution

ZK programs: - zk-id — Identity verification with Groth16 proofs - zk/nullifier — Simple nullifier creation program

Additional: examples-zk-compression — More ZK compression examples

Canonical source: program-examples README. If cloned locally, scope Read, Glob, Grep to these repositories and the current project directory only.

Workflow

1. Clarify intent
2. Recommend plan mode, if it's not activated
3. Use AskUserQuestion to resolve blind spots
4. All questions must be resolved before execution
5. Identify references
6. Match task to domain references and reference repos
7. Locate relevant documentation and examples
8. Write plan file (YAML task format)
9. Use AskUserQuestion for anything unclear — never guess or assume
10. Identify blockers: permissions, dependencies, unknowns
11. Plan must be complete before execution begins
12. Execute
13. Use Task tool with subagents for parallel research
14. Subagents load skills via Skill tool
15. Track progress with TodoWrite
16. When stuck: ask to spawn a read-only subagent with Read, Glob, Grep, and DeepWiki MCP access, loading skills/ask-mcp. Scope reads to skill references, example repos, and docs.

Build and test

Required commands

Anchor programs:

anchor build
anchor test

Native programs:

cargo build-sbf
cargo test-sbf

Forbidden shortcuts

• Do NOT use cargo build (must use cargo build-sbf)
• Do NOT use cargo test (must use cargo test-sbf)
• Do NOT skip SBF compilation
• Tests MUST run against real BPF bytecode

Failure recovery

On failure, spawn debugger agent with error context.

Loop rules: 1. Each debugger gets fresh context + previous debug reports 2. Each attempt tries something DIFFERENT 3. NEVER GIVE UP - keep spawning until fixed 4. Max 5 attempts per error

Do NOT proceed until all tests pass.

SDK references

Package	Link
light-sdk	docs.rs
light-client	docs.rs
@lightprotocol/stateless.js	API docs
light-program-test	docs.rs

DeepWiki fallback

If no matching pattern in reference repos:

mcp__deepwiki__ask_question("Lightprotocol/light-protocol", "How to {operation}?")

Security

This skill provides code patterns and documentation references only.

• Declared dependencies. Devnet and mainnet examples require API_KEY (Helius or Triton RPC key) and read ~/.config/solana/id.json for the payer keypair. Neither is needed on localnet. In production, load both from a secrets manager.
• Filesystem scope. Read, Glob, and Grep must be limited to the current project directory and the reference repos listed above. Do not read outside these paths.
• Subagent scope. When stuck, the skill asks to spawn a read-only subagent with Read, Glob, Grep scoped to skill references, example repos, and docs.
• Install source. npx skills add Lightprotocol/skills from Lightprotocol/skills.
• Audited protocol. Light Protocol smart contracts are independently audited. Reports are published at github.com/Lightprotocol/light-protocol/tree/main/audits.