> ## Documentation Index
> Fetch the complete documentation index at: https://sella.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Sella FAQ: questions from consumers and publishers

> Answers to common questions about Sella — for consumers (wallets, chains, payments, errors) and publishers (grading, listings, payouts).

Find answers to the most common questions about Sella below. Questions are grouped by audience — start with General if you're new, then jump to the section that fits your role.

## General

<AccordionGroup>
  <Accordion title="What is Sella, in one sentence?">
    A marketplace where AI agents autonomously discover, evaluate, and buy datasets, models, compute, and APIs — paying per use over the [x402](/reference/x402) protocol, all through [MCP](/reference/mcp-tools).
  </Accordion>

  <Accordion title="Do I need to be an agent to use it?">
    No. Agents are the primary consumers, but a human operator sets everything up: funding, budgets, and policies. See [Operating agents](/consumers/operators). Publishers are people and companies who supply the marketplace.
  </Accordion>

  <Accordion title="What does it cost?">
    Discovery and evaluation are free. You pay per access for paid listings, and fixed fees for compute — $10 for Cradle and $15 for Mergekit. Publishers pay a 3% platform fee on earnings.
  </Accordion>
</AccordionGroup>

## For consumers

<AccordionGroup>
  <Accordion title="How do I connect my agent?">
    Add the MCP server at `https://sellag.vercel.app/api/mcp` and authenticate using `sella_auth_start` and `sella_auth_complete`. See [Connect your agent](/consumers/connect) and the [Quickstart](/consumers/quickstart).
  </Accordion>

  <Accordion title="Where do my private keys live?">
    On your machine, in `~/.sella-wallet.json`. Sella is non-custodial — it stores only your public addresses and can never sign transactions on your behalf.
  </Accordion>

  <Accordion title="Which chains can I pay on?">
    Base, Solana, and Stellar are live. Ethereum and Tempo are in preview for the API Data Market. Sui and Aptos are planned. The runtime `402` challenge tells you exactly which chain to use for each purchase.
  </Accordion>

  <Accordion title="A call failed with WALLET_UNFUNDED — now what?">
    Your wallet balance is too low to cover the payment. [Fund it](/consumers/operators) from the dashboard or by sending USDC directly to your wallet address, then retry the call.
  </Accordion>

  <Accordion title="Can I try data before paying?">
    Yes — the `try_dataset` tool gives you schema coverage, sample rows, and the full quality datacard for free, with no payment required. See [Evaluate](/consumers/evaluate).
  </Accordion>

  <Accordion title="Is there a way in without an agent framework?">
    Yes — the MCP endpoint is plain JSON-RPC over HTTP, and the catalogue is also readable via the [REST API](/reference/rest-api). That said, transactional flows (buying, compute, proxying APIs) are smoothest through MCP because the tools handle the x402 handshake automatically.
  </Accordion>
</AccordionGroup>

## For publishers

<AccordionGroup>
  <Accordion title="What can I publish?">
    Datasets, APIs, and pipelines including Cradle and Merge jobs and custom compute. See [Publishing on Sella](/publishers/overview).
  </Accordion>

  <Accordion title="How do I get paid?">
    Every paid access settles to your wallet in USDC, minus the 3% platform fee. Withdraw to an external wallet or liquidate to fiat from the dashboard. See [Pricing & earnings](/publishers/pricing).
  </Accordion>

  <Accordion title="Why isn't my dataset showing up?">
    Only listings in `live` or `manual_review` state appear in public listing and search results. Check your [publish state](/publishers/datasets) — listings in `draft` or `process` are invisible to agents.
  </Accordion>

  <Accordion title="How do I improve my listing's grade?">
    Complete the ADC metadata fields, make your preview representative of the full dataset, and scope tasks honestly — then re-process to rebuild the datacard with updated scores. See [Quality & datacards](/publishers/quality).
  </Accordion>

  <Accordion title="Do I hand my API keys to buyers?">
    Never. Agents authenticate to Sella, which proxies calls to your API on their behalf. Your upstream credentials stay with you at all times. See [Listing APIs](/publishers/apis).
  </Accordion>
</AccordionGroup>

***

<Card title="Open Sella" icon="arrow-up-right" href="https://sellag.vercel.app">
  Head to the app to manage your account, wallets, and listings.
</Card>