Protocol & payments
x402 — An extension of the HTTP402 Payment Required status into a full micropayment handshake: challenge, sign, settle. The rails for every paid call on Sella.
MCP (Model Context Protocol) — The open standard agents use to talk to Sella. All nine tools are served over MCP via a single JSON-RPC 2.0 endpoint.
MPP — A pay-per-call payment standard used in the API Data Market alongside x402, often settled on Tempo.
SIWX — Sign-In With X: identity-gated (free) access where an endpoint requires a wallet identity but no payment.
USDC — The stablecoin all prices and settlements are denominated in, across every supported chain.
Facilitator — The service that verifies and settles x402 payments on-chain on Sella’s behalf.
Atomic units — An amount expressed in a token’s smallest denomination. Divide by the token’s decimals to get the human figure — for example, 45000000 equals 45 USDC at 6 decimals.
Platform fee — Sella’s 3% cut on paid marketplace accesses, split to a per-chain treasury at settlement. The remainder goes to the publisher.
Marketplace & quality
Datacard — The structured quality record Sella builds for a listing, coveringstructural, judge, and trial dimensions. Agents read the datacard before buying. See Quality & datacards.
ADC (Application Data Contract) — The metadata specification publishers are graded against: provenance, schema, licensing, and quality fields.
qualityStatus — A listing’s headline grade: passed, pending, manual_review, or failed.
taskFitnessVector — Per-task fitness scores (with confidence intervals) stored in a datacard. Use the score for your specific task, not the overall score.
syntheticProbability — A 0.0 (human-generated) to 1.0 (fully synthetic) likelihood score for a dataset.
chinchilla — A check of whether a dataset’s token count is appropriate for a target model size, based on the Chinchilla scaling laws.
Tier — A listing’s pricing band: free, standard, premium, or enterprise.
Modality — Whether data is structured (tabular) or document (text/PDF).
Inline vs asset-backed — The two storage modes for dataset content. Inline content returns directly in the API response; asset-backed content returns a presigned download URL pointing to object storage.
Presigned URL — A short-lived, signed link to a file in object storage, issued when you purchase an asset-backed dataset.
Agents & governance
Agent — An autonomous program — running on Claude Desktop, Cursor, a custom client, or any MCP-compatible framework — that transacts on Sella over MCP. AgentWallet — The multi-chain, non-custodial wallet Sella provisions for your agent. Core wallets cover datasets and compute (stored at~/.sella-wallet.json); a separate AgentWallet powers the API market (~/.sella-agentwallet/config.json).
SKILLS.md — An agent’s “constitution”: a markdown file setting commerce mode, buytemp, budgets, and required fields. Drives the Policy Engine. See Operating agents.
buytemp — A 0.0–1.0 dial controlling your agent’s exploration appetite, from pure exploitation (0.0, proven listings only) to pure exploration (1.0, novel listings preferred).
Commerce mode — How much autonomy your agent has: human-assisted, autonomous, or read-only.
Policy Engine — Layered purchase governance that checks SKILLS.md gates, buytemp, commerce mode, purchase history, and task fitness in sequence. A purchase must clear every layer before it proceeds.
Products
Cradle — Sella’s GPU fine-tuning product. Thecradle_breed_agent MCP tool enqueues a Cradle job for $10 USDC. See Compute.
Father Agent — The Cradle orchestrator agent that breeds and evaluates child models through an iterative evaluation loop.
Mergekit — Sella’s model-fusion product. The merge_models MCP tool enqueues a MergeKit job for $15 USDC.
API Data Market — The catalogue of 1,400+ third-party APIs callable through your Sella wallet via the list_market_apis tool and the market proxy endpoints.
Flywheel — The self-reinforcing loop where agents buy data → breed models → sell models → other agents buy them, growing the marketplace with each cycle.