# Probarion docs > A mandate layer for AI agents on NEAR. The agent pays only inside mandates its owner signed, a NEAR contract checks every payment, and the owner can publish the signed ledger for anyone to verify. Rules for agents reading these docs: 1. Status words mean what they say. Live works in this deployment. Preview is built but not yet run end to end, or not open yet. Planned is not built. 2. NEAR testnet is live. On mainnet one small vault is live, `v0.probarion.near`, since 2026-11-11: no mainnet factory is deployed, and no Base payout has run on mainnet. 3. The packages are on npm. To run the evaluation, the fixtures or the scripts, build from a clone, as /docs/build/install shows. 4. An agent key can call only `spend`. Owner and approver actions are signed by a person, not by Probarion and not by an agent. 5. A spend request has no payee field. Do not look for one and do not add one. 6. Do not resend a spend whose outcome is `unconfirmed`. First look for its `ref` in the vault's spend list. 7. A contract refusal reads `PROBARION:`. Each code is explained at /docs/build/errors#\. 8. Each page names the day it was reviewed and the commit the docs were built from: its Markdown twin in its first lines, and every HTML page but the docs home in its source box. Where a page and the code disagree, the code wins. 9. When you build or review the repository, follow AGENTS.md. ## Docs home - [Probarion docs](https://probarion.xyz/docs.md): Guides, references and verify-it-yourself recipes for Probarion, a mandate layer that lets AI agents pay on NEAR only inside limits an owner signed. ## Start here - [What is Probarion](https://probarion.xyz/docs/start/what-is-probarion.md): Probarion is a mandate layer for AI agents on NEAR: an owner signs spending limits, a vault contract checks every payment, a signed ledger records it. - [How one payment works](https://probarion.xyz/docs/start/how-one-payment-works.md): Follow one payment from the owner's mandate through code, the vault's 14 checks and the signed ledger to a record the owner can publish for anyone to verify. - [Evaluate in 5 minutes](https://probarion.xyz/docs/start/evaluate-in-5-minutes.md): Check Probarion with no wallet or key: build from source, run the verifier on a test ledger, and read the testnet vault on chain. - [Owner quickstart](https://probarion.xyz/docs/start/owner-quickstart.md): Sign in with a NEAR wallet, create a testnet vault, add test USDC, add the agent and ledger keys, and sign your first mandate in the console. - [Developer quickstart](https://probarion.xyz/docs/start/developer-quickstart.md): Build the SDK from source, have the owner add your keys and sign a mandate, run one testnet payment with process() and handle each status. - [Testnet and mainnet](https://probarion.xyz/docs/start/testnet-and-mainnet.md): Probarion runs on NEAR testnet with test tokens today, and one small vault on mainnet. What differs between the two networks and how the site picks one. - [What works today](https://probarion.xyz/docs/start/what-works-today.md): What is live, in preview or planned in Probarion today, from the same status list as the home page, plus more parts that list leaves out. ## Concepts - [Vaults, roles and keys](https://probarion.xyz/docs/concepts/vaults-roles-and-keys.md): Who can do what on a Probarion vault: the owner, approvers, spend-only agent keys and the anchor-only ledger key, and why most owner calls need 1 yoctoNEAR. - [Why spend has no payee](https://probarion.xyz/docs/concepts/why-spend-has-no-payee.md): The agent's spend request has no address field. The vault pays the payee the owner set in the mandate, so a hijacked prompt cannot pick where money goes. - [Mandates](https://probarion.xyz/docs/concepts/mandates.md): Every field of a mandate, what the contract checks when the owner signs one, why a mandate is never edited, and why an expired one can still read active. - [How a payment is checked](https://probarion.xyz/docs/concepts/payment-checks.md): The vault runs 14 checks in a fixed order on every spend; the first failure is the answer. Amount limits are inclusive. Dry-run one with check_spend. - [Holds and approvals](https://probarion.xyz/docs/concepts/holds-and-approvals.md): When a spend waits for a person, who may approve or reject it, when the hold expires, and how a hold by code differs from a hold on chain. - [The ledger and anchors](https://probarion.xyz/docs/concepts/ledger-and-anchors.md): How each decision is signed into a hash-chained ledger before the spend is sent, and how anchors pin it on chain so a rewritten anchored range is caught. ## Build - [Install the packages](https://probarion.xyz/docs/build/install.md): Install the Probarion SDK, core and CLI 0.1.1 from npm on Node 24, or build them from source with pnpm 10, then check the build and import it. - [Let an agent pay](https://probarion.xyz/docs/build/let-an-agent-pay.md): Wire your agent to a vault with process(): keys, invoice facts, code-only or model advice, one ledger writer, refs and retries, and outcomes. - [Spend outcomes](https://probarion.xyz/docs/build/spend-outcomes.md): Every status process() and requestSpend() return: what spendId, code and txHash mean, and what to do next. Never resend an unconfirmed spend. - [Errors](https://probarion.xyz/docs/build/errors.md): Every vault panic code with its meaning and next step, the SDK error classes, the transaction failure codes and the hosted app's HTTP errors. - [SDK reference](https://probarion.xyz/docs/build/sdk-reference.md): Every export of @probarion/sdk and @probarion/sdk/testing: the Probarion client, chain clients, ledger stores, model adapter, proof, errors and test doubles. - [Policy rules](https://probarion.xyz/docs/build/policy-rules.md): Every rule id decide() can record, with its effect, the vault code it mirrors, the exact condition in the code, and what to do next. - [CLI reference](https://probarion.xyz/docs/build/cli-reference.md): Every probarion CLI command and option, with required flags, defaults, who signs each printed transaction, its gas and deposit, and the exit codes. - [Contract reference](https://probarion.xyz/docs/build/contract-reference.md): Every method of the Probarion vault and factory contracts on NEAR: kind, caller, deposit, arguments, return value, events and error codes. - [Events](https://probarion.xyz/docs/build/events.md): Every NEP-297 event the vault and factory contracts log: its name, the method that emits it, its fields and types, and how to read them from receipts. - [HTTP API](https://probarion.xyz/docs/build/http-api.md): Every route under /api of the hosted app, and the proof page's files, by group: who may call it, what it takes and answers, its errors and its rate limit. - [Limits and costs](https://probarion.xyz/docs/build/limits-and-costs.md): The limits the vault, the factory and the hosted app enforce, the deposit and gas of each call, and what a vault spends from its own NEAR. ## Verify and trust - [Verify a vault yourself](https://probarion.xyz/docs/trust/verify-a-vault.md): Run the Probarion verifier: offline on the committed fixture, live against a testnet vault, and on the files of a proof page you can open. Real output. - [Verifier checks a to i](https://probarion.xyz/docs/trust/verifier-checks.md): The nine checks the verifier runs, a to i: what a pass on each one proves, what it leaves to trust, and when one can skip or be unproven. - [Security model](https://probarion.xyz/docs/trust/security-model.md): Who holds which key, what the vault enforces, the loss bounds if a key leaks, how to stop a vault, the known gaps, and how to report a flaw. - [The agent key cannot approve itself](https://probarion.xyz/docs/trust/self-approval.md): What the I-HITL paper found, why a Probarion agent key cannot raise its limit or approve itself, the test that replays the attack, and its gaps. - [Reproducible builds](https://probarion.xyz/docs/trust/reproducible-builds.md): Rebuild the Probarion vault or factory wasm in Docker, as CI does, and match the code hash recorded in the repository and deployed on NEAR testnet. ## Operate - [Architecture](https://probarion.xyz/docs/operate/architecture.md): How Probarion fits together: the vault and factory on NEAR, who signs, the hosted app and the outside services, each part tied to its code. ## Resources - [Glossary](https://probarion.xyz/docs/resources/glossary.md): Plain definitions of the words the Probarion docs use, from owner and mandate to anchor and verifier check, with the code name where there is one. - [For AI agents](https://probarion.xyz/docs/resources/for-ai-agents.md): How an AI agent reads these docs: a Markdown twin of every page, /llms.txt and /llms-full.txt, and the rules it follows when it acts on them. - [Changelog](https://probarion.xyz/docs/resources/changelog.md): Every change to the contracts, the npm packages, the CLI and the web console, rendered from the repository CHANGELOG.md of this build. ## Optional - [All docs in one file](https://probarion.xyz/llms-full.txt): every page above, as Markdown