Arcium Encrypted Solana Computation

What it does

When your agent uses it

• Writing your first Arcium encrypted computation app on Solana
• Debugging an Arcium callback, nonce or ArgBuilder ordering failure
• Deciding between Shared and Mxe encrypted state for a circuit
• Designing a sealed-bid auction, encrypted vote or hidden game state

Example prompts

• “Walk me through building my first Arcium circuit and Anchor program.”
• “My Arcium callback never fires. Help me debug the queue_computation and callback wiring.”
• “Should this encrypted auction use Shared or Mxe state for the bid amounts?”

Requirements

• The arcium CLI (wraps Anchor)
• The @arcium-hq/client TypeScript package
• The bundled Arcium MCP server
• Compatibility (from SKILL.md): Bundled mcp.json configures the Arcium MCP server automatically.

Workflow steps

7 steps, taken from the first numbered list in SKILL.md.

1. 1Names match exactly — #[instruction] fn NAME must match across #[arcium_callback(encrypted_ix = "NAME")], comp_def_offset("NAME"), and all…
2. 2Comp def initialized — init_*_comp_def must be called once before any computation
3. 3ArgBuilder param order — calls must match circuit fn parameters left-to-right
4. 4Shared params include pubkey — .x25519_pubkey() before .plaintext_u128(nonce) before ciphertexts (missing = silent failure)
5. 5Nonce is unique — fresh randomBytes(16) per encryption, same nonce passed to program
6. 6Callback registered and writable — callback_ix(...) passed in queue_computation call, accounts set in BOTH CallbackAccount { pubkey…
7. 7Environment correct — cluster offset matches network, MXE public key available (retry with backoff), RPC endpoint reliable

What it can do on your machine

Read from SKILL.md and the folder at commit 06b36b8. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are rust).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Links to these hosts (documentation or services it may open):

  • docs.arcium.com
  • github.com
  • ts.arcium.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

• Compatibility

  Bundled mcp.json configures the Arcium MCP server automatically.

  From compatibility in the SKILL.md frontmatter.

Context cost

Arcium Encrypted Solana Computation loads about 2.8k tokens when it runs, and up to ~5.9k if it reads all its reference files. Until then it costs about 163 tokens; SKILL.md has 983 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~163

When it runs · the whole SKILL.md, loaded when a task matches

~2.8k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~5.9k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from sendaifun/skills at commit 06b36b8, republished under its MIT licence (© sendaifun). 983 words, ~2,814 tokens.

name

arcium

description

Build and debug encrypted Solana applications with Arcium — data stays private during computation, no single party sees it. Use when writing Arcis circuits (#[encrypted], #[instruction]), wiring Anchor programs with init/queue_computation/callback flows, choosing Shared vs Mxe encrypted state, encrypting inputs with @arcium-hq/client (RescueCipher, x25519), or debugging ArgBuilder ordering, nonce, callback, or computation finalization failures. Covers dark pools, sealed-bid auctions, encrypted voting, hidden game state, confidential DeFi, secure randomness, and threshold signing. Also use for getting started with your first Arcium app.

compatibility

Bundled mcp.json configures the Arcium MCP server automatically.

license

MIT

metadata.author

arcium-hq

metadata.version

2.1

const COMP_DEF_OFFSET_FLIP: u32 = comp_def_offset("flip");

// 1. INIT (once per instruction type)
pub fn init_flip_comp_def(ctx: Context<InitFlipCompDef>) -> Result<()> {
    init_comp_def(ctx.accounts, None, None)
}

// 2. QUEUE (each computation)
pub fn flip(ctx: Context<Flip>, offset: u64, ...) -> Result<()> {
    let args = ArgBuilder::new()...build();
    queue_computation(ctx.accounts, offset, args,
        vec![FlipCallback::callback_ix(offset, &ctx.accounts.mxe_account, &[])?],
        1, 0,
    )?;
    Ok(())
}

// 3. CALLBACK (after MPC completes)
#[arcium_callback(encrypted_ix = "flip")]
pub fn flip_callback(ctx: Context<FlipCallback>,
    output: SignedComputationOutputs<FlipOutput>) -> Result<()> {
    let result = output.verify_output(...)?;
    // Use result...
}

© sendaifun, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 4 other files (references) in skills/arcium of sendaifun/skills.

• SKILL.md
• examples/minimal-circuit.md
• examples/patterns.md
• mcp.json
• references/troubleshooting.md

Open the folder on GitHubat commit 06b36b8