Coinbase's developer platform pairs Server Wallets in AWS Nitro Enclaves with AgentKit, the most widely integrated open agent framework, and prices it per operation. Coldstar is what you use when the agent's authority should not originate in Coinbase's cloud, even a very well-run one.
AgentKit as the agent framework with Coldstar as the wallet provider is a clean split: Coinbase's tooling, your root.
| Coldstar | Coinbase CDP Wallets | |
|---|---|---|
| Who holds the root key | You. The cold root lives encrypted on your own USB drive. No vendor holds a key, a share, or an account. | Coinbase's enclaves. Private-key operations happen inside the enclave boundary, not accessible to CDP, AWS, or other components per Coinbase. The developer holds a rotatable P-256 Wallet Secret that authorises writes. |
| Where the key lives | On your machine. The air-gapped root signs a bounded policy envelope; a disposable session key signs routine transactions inside it. | AWS Nitro Enclaves: no persistent storage, no interactive access, no external networking. |
| Policy engine | Per-transaction limit, daily cap, program allowlist, recipient allowlist and blocklist, escalate-above threshold. Evaluated locally, first match wins, before any signature exists. | Solana criteria: recipient address in/not-in, SOL value ≤, mint address, program ID, SPL address and value range, message regex, network; Anchor IDL policies. Project or account scope. No daily or cumulative limits, no time windows. Where evaluation runs is not stated on the policy pages. |
| Out-of-policy transactions | ESCALATE to a human over air-gapped QR, or REJECT. No signature is produced for a rejected transaction. | Denied. No per-transaction human approval documented; 2FA protects developer credentials. |
| Cold / offline root | Yes — the root key never touches a networked machine. | No. Online Nitro service. |
| Agent integration | Framework-agnostic: the agent proposes an unsigned transaction, the signer decides. CLI signer today; MCP server in progress. | AgentKit (Apache-2.0): LangChain, Vercel AI SDK, MCP, OpenAI Agents SDK; wallet providers CDP, Privy, viem; TypeScript and Python; EVM and SVM. |
| Solana support | Solana mainnet. Core is chain-agnostic; EVM signing exists. | Yes: sign and send Solana transactions, sponsored transactions, Solana policy criteria. |
| Source & self-hosting | Open source (MIT), self-hosted. No API key, no SaaS dependency, nothing to go down. | AgentKit and cdp-sdk open; enclave code closed; customer verification of attestation not documented. Hosted only. |
| Pricing | Free software plus a ~$10 drive. | $0.005 per wallet write operation (create, sign, broadcast, policy evaluation); 5,000 free operations per month; reads free. Figures from a first-party search snippet; the pricing page returned 403 to our fetch. |
| Maturity | Beta — the signing core and policy engine are in scope for the planned independent audit. | Production; audits or SOC 2 not stated on the security page we fetched. |
AgentKit is excellent and open, and nothing about Coldstar asks you to give it up. The comparison is the wallet underneath it.
CDP's design is clean: keys live and sign inside Nitro Enclaves, and your backend authorises operations with a rotatable secret. The enclave protects the key from Coinbase's own staff and from AWS. What it cannot protect is the secret in your backend: whoever holds it can drive the wallet within policy, and policy is per-transaction only.
Coldstar assumes the backend will eventually be compromised and bounds the damage. The root is offline on your drive; the agent's session key is disposable; the daily cap and allowlists are enforced before any signature exists; anything over the escalate threshold waits for a human with a phone and a QR code.
CDP is production infrastructure from a public company. Coldstar is beta, pre-audit.
AgentKit supports multiple wallet providers. A Coldstar policy-gated session key can back an AgentKit agent, giving you Coinbase's tooling with an owner-held cold root.
Coinbase markets it that way: keys exist only in its enclaves and it states they are not accessible to CDP. Operationally, the key is on Coinbase-run infrastructure and your backend holds the secret that authorises use. Coldstar's root is a file on a drive you own.
Its documented Solana policy criteria are per-transaction: value thresholds, address and program lists, regex on messages. No daily or rolling caps at review time.
Yes. AgentKit's wallet-provider abstraction is designed for that, and Coldstar's session key can serve as the provider.
Open source, MIT. macOS, Linux, Windows — and on the Solana Seeker dApp Store.
pip install coldstar
Third-party facts were checked against the vendor's own pages on the date above. Pricing and feature sets change; if something here is out of date, tell us and we will fix it.