Agent credentials

An agent on Linkex is a bring-your-own wallet paired with a dedicated API key. Linkex verifies you own the wallet once, then stores only the public address — no private key ever touches the platform. The wallet is the agent's identity; the key is what it authenticates with.

Create an agent

Open the Agents page

Go to Console → Agents. Agent management is gated behind a wallet-verified session — if prompted, connect and verify your account wallet first (SIWE). Click Create Agent.

Name it and pick a chain

Give the agent a label (up to 128 characters) and choose the credential chain:

EVM — one address works across Base and BNB Chain
Solana

Prove wallet ownership

Connect the wallet that will be the agent and sign a one-time ownership proof:

EVM — an EIP-712 typed-data signature. Domain name linkexai-agent-ownership, primary type AgentOwnership { agent, nonce, issuedAt }.
Solana — an ed25519 signature over the canonical message linkexai-agent-ownership\nagent: <address>\nnonce: <nonce>\nissuedAt: <unix>.

The nonce is single-use and the timestamp must be fresh (within 5 minutes), so a captured signature can't be replayed.

Save the API key — shown only once

On success Linkex mints the agent's API key (sk-...) and displays it one time only. Download the backup JSON or copy the key now; it cannot be retrieved later (revoke and re-register if lost).

Programmatic creation uses the same two endpoints — POST /api/user/self/agents/siwe/nonce then POST /api/user/self/agents; see the API reference.

Spend caps

Each agent carries three optional USD caps, enforced when the agent funds itself over x402 (settlement fails with SPEND_CAP_EXCEEDED beyond them):

Cap	Meaning
`per_call_cap_usd`	Max USD per single top-up
`daily_cap_usd`	Max USD per calendar day
`total_cap_usd`	Lifetime max USD

0 means uncapped. Current spend counters (spent_today_usd, spent_total_usd) are visible on the Agents page and in GET /api/user/self/agents.

Using the agent key

The agent key works everywhere a normal key does:

# inference
curl https://linkex.ai/v1/chat/completions -H "Authorization: Bearer sk-AGENT_KEY" ...

# check its balance (shared account balance)
curl https://linkex.ai/api/user/self/balance -H "Authorization: Bearer sk-AGENT_KEY"

# create a top-up order — automatically bound to this agent, caps enforced
curl -X POST https://linkex.ai/api/user/topup/x402/orders \
  -H "Authorization: Bearer sk-AGENT_KEY" -d '{"amount_usd": 5}'

When authenticated with an agent key, x402 orders are force-bound to that agent's wallet — an agent_wallet_id in the request body is ignored. This is what makes the caps tamper-proof from the agent's side.

Revoke

Click Revoke on the Agents page (or DELETE /api/user/self/agents/{agent_id}). In a single transaction the API key is disabled and the wallet unlinked. Revocation is idempotent, and the same wallet can be re-registered later — it gets a fresh key.

Limits

Up to 50 agents per account.
EVM addresses are stored lowercased; Solana addresses are case-sensitive base58.
One wallet address can be registered as an agent only once at a time (re-registerable after revocation).

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