SchemaSure Chain API
The Chain API from SchemaSure — 1 operation(s) for chain.
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OpenAPI Specification
openapi: 3.2.0
info:
title: ChainState Chain API
version: 0.1.0
summary: 'One-call Base address profile for agents: code, proxy, interfaces, token, balances, denylist.'
description: 'ChainState answers everything an agent needs to know about a Base address before interacting with it, in one paid call rather than four to six a-la-carte lookups. It reports whether the address holds code and how much, resolves proxies across all seven known slot layouts — including the legacy OpenZeppelin slot that Base USDC really uses, which an EIP-1967-only detector misses entirely — and returns the implementation behind the indirection, ERC-165 interface support, behavioural ERC-20 detection, token metadata, and the balances you asked for. There is no model anywhere in it. A contract that does not answer supportsInterface is reported as null, never false, and there is deliberately no reverse-name field: a name the subject can set for itself, published without a forward check, would be the one spoofable value in the response.'
contact:
email: support@schemasure.com
x-policy-version: '2026-09-19'
servers:
- url: https://chainstate.schemasure.com
tags:
- name: Chain
paths:
/v1/chain/state:
post:
operationId: chainstate_v1_chain_state
summary: 'Profile a Base address: code, proxy, interfaces, token metadata, balances…'
description: Profile a Base address in one call instead of four to six lookups. Returns contract or externally owned plus code size, proxy detection across all seven slot layouts including the legacy OpenZeppelin slot Base USDC uses, the resolved implementation, ERC-165 and behavioural ERC-20 detection, token metadata, requested ERC-20 balances, and denylist hits. Answers unknown rather than guessing, and null rather than false when a contract stays silent. Not a guarantee that an address is safe.
x-payment-info:
offers:
- method: tempo
intent: charge
amount: '20000'
currency: '0x20C000000000000000000000b9537d11c60E8b50'
recipient: '0x9876af0F6D8Ed5155Cd02d1ca56D128601612690'
methodDetails:
chainId: 4217
supportedModes:
- pull
x402Version: 2
scheme: exact
network: eip155:8453
asset: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
amountAtomic: '20000'
priceUsd: 0.02
payTo: '0x9876af0F6D8Ed5155Cd02d1ca56D128601612690'
policy: charge only on a successful, usable result
requestBody:
required: true
content:
application/json:
schema:
$schema: https://json-schema.org/draft/2020-12/schema
title: ChainStateRequest
type: object
additionalProperties: false
required:
- address
properties:
address:
type: string
pattern: ^0x[0-9a-fA-F]{40}$
description: The Base address to profile. Case-insensitive; normalised to EIP-55.
tokens:
type: array
maxItems: 10
items:
type: string
pattern: ^0x[0-9a-fA-F]{40}$
description: ERC-20 contracts to read balanceOf(address) on for the subject. Amounts come back in base units with the token's decimals, or null with a reason.
selector:
type: string
pattern: ^0x[0-9a-fA-F]{8}$
description: Only used for EIP-2535 diamonds, which have no single implementation and resolve their executing code per selector. Ignored for every other proxy kind.
example:
address: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
responses:
'200':
description: Successful result envelope
headers:
Payment-Receipt:
description: MPP Tempo settlement receipt
schema:
type: string
PAYMENT-RESPONSE:
description: x402 settlement receipt
schema:
type: string
content:
application/json:
schema:
$schema: https://json-schema.org/draft/2020-12/schema
title: ChainStateEnvelope
type: object
required:
- ok
- verdict
- confidence
- risk_codes
- evidence
- result
- policy_version
- request_hash
- data_versions
- warnings
properties:
ok:
type: boolean
verdict:
type: string
enum:
- allow
- warn
- block
- unknown
description: 'Precedence: block, then unknown, then warn, then allow.'
confidence:
type: number
minimum: 0
maximum: 1
risk_codes:
type: array
items:
type: string
evidence:
type: array
items:
type: object
policy_version:
type: string
request_hash:
type: string
pattern: ^sha256:[0-9a-f]{64}$
warnings:
type: array
items:
type: string
data_versions:
type: object
required:
- denylist
- abi_packs
- proxy_slots
- policy
- chain
result:
type: object
required:
- address
- chain
- account
- proxy
- interfaces
- token
- balances
- denylist_hits
- unresolved
- rpc
properties:
account:
type: object
required:
- is_contract
- code_size
- detail
properties:
is_contract:
type:
- boolean
- 'null'
description: null means the contract did not answer. It never means 'does not support'.
code_size:
type:
- integer
- 'null'
proxy:
type: object
required:
- kind
- implementation
- upgradeable
- slots_probed
- detail
properties:
kind:
type: string
enum:
- none
- eip1167
- eip1967
- eip1967-beacon
- eip1822
- zeppelinos
- diamond
- unknown
upgradeable:
type:
- boolean
- 'null'
description: null means the contract did not answer. It never means 'does not support'.
interfaces:
type: object
required:
- erc165
- erc721
- erc1155
- erc20
- detail
properties:
erc165:
type:
- boolean
- 'null'
description: null means the contract did not answer. It never means 'does not support'.
erc721:
type:
- boolean
- 'null'
description: null means the contract did not answer. It never means 'does not support'.
erc1155:
type:
- boolean
- 'null'
description: null means the contract did not answer. It never means 'does not support'.
erc20:
type:
- boolean
- 'null'
description: null means the contract did not answer. It never means 'does not support'.
token:
type:
- object
- 'null'
balances:
type: array
items:
type: object
unresolved:
type: array
items:
type: string
example:
ok: true
verdict: warn
confidence: 1
risk_codes:
- PROXY_UPGRADEABLE
evidence:
- code: INTERFACE_PROBE_UNANSWERED
severity: info
detail: 'This contract did not answer supportsInterface, so ERC-721 and ERC-1155 support is reported as null. That is not evidence against them: plenty of live contracts predate ERC-165 entirely.'
source: erc165
- code: PROXY_UPGRADEABLE
severity: medium
detail: This is an upgradeable zeppelinos proxy. Everything reported here describes the implementation deployed right now; the admin can point it elsewhere before your next call lands, so this is a risk signal rather than metadata.
source: proxy-slots
data:
kind: zeppelinos
implementation: '0x2Ce6311ddAE708829bc0784C967b7d77D19FD779'
admin: '0x4fc7850364958d97B4d3f5A08f79db2493f8cA44'
result:
address: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
chain: eip155:8453
account:
is_contract: true
code_size: 1852
detail: 1852 bytes of runtime code
proxy:
address: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
kind: zeppelinos
implementation: '0x2Ce6311ddAE708829bc0784C967b7d77D19FD779'
admin: '0x4fc7850364958d97B4d3f5A08f79db2493f8cA44'
beacon: null
upgradeable: true
slots_probed:
- slot: '0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc'
label: eip1967.implementation
value: '0x0000000000000000000000000000000000000000000000000000000000000000'
address: null
- slot: '0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103'
label: eip1967.admin
value: '0x0000000000000000000000000000000000000000000000000000000000000000'
address: null
- slot: '0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50'
label: eip1967.beacon
value: '0x0000000000000000000000000000000000000000000000000000000000000000'
address: null
- slot: '0xc5f16f0fcc639fa48a6947836d9850f504798523bf8c9a3a87d5876cf622bcf7'
label: eip1822.uups
value: '0x0000000000000000000000000000000000000000000000000000000000000000'
address: null
- slot: '0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3'
label: zeppelinos.implementation
value: '0x0000000000000000000000002ce6311ddae708829bc0784c967b7d77d19fd779'
address: '0x2Ce6311ddAE708829bc0784C967b7d77D19FD779'
- slot: '0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b'
label: zeppelinos.admin
value: '0x0000000000000000000000004fc7850364958d97b4d3f5a08f79db2493f8ca44'
address: '0x4fc7850364958d97B4d3f5A08f79db2493f8cA44'
- slot: '0xc8fcad8db84d3cc18b4c41d551ea0ee66dd599cde068d998e57d5e09332c131c'
label: eip2535.diamond
value: '0x0000000000000000000000000000000000000000000000000000000000000000'
address: null
detail: resolved through the legacy zeppelinos slot; the EIP-1967 slot is empty on this contract, which is the case for Base USDC
interfaces:
erc165: null
erc721: null
erc1155: null
erc20: true
detail: supportsInterface did not answer, so ERC-721 and ERC-1155 are reported as unknown rather than absent; ERC-20 is confirmed behaviourally from totalSupply, decimals, and balanceOf
token:
symbol: USDC
decimals: 6
total_supply: '4305008625389354'
detail: symbol, decimals, and totalSupply read from the token
balances: []
denylist_hits: []
unresolved:
- 'ERC-165 interface support: supportsInterface did not answer'
rpc:
configured: true
reachable: true
endpoints:
- url: https://mainnet.base.org
latest: true
archive: true
simulate: true
policy_version: '2026-09-19'
request_hash: sha256:96b41fa639c553a6dc6bfaa1d8ccc056912abc36e8bbde3d65f3e1edc2bd147f
data_versions:
denylist: 2026-08-03.1
abi_packs: 2026-08-03.1
proxy_slots: '7'
policy: '2026-09-19'
chain: eip155:8453
warnings: []
'400':
description: INPUT_INVALID
content:
application/json:
schema:
type: object
required:
- error
additionalProperties: false
properties:
error:
type: object
required:
- code
- message
properties:
code:
type: string
message:
type: string
details: {}
'402':
headers:
WWW-Authenticate:
description: MPP tempo/charge challenge
schema:
type: string
PAYMENT-REQUIRED:
description: x402 payment challenge
schema:
type: string
description: 'Payment required. Choose x402 (PAYMENT-REQUIRED / PAYMENT-SIGNATURE) or MPP Tempo (WWW-Authenticate / Authorization: Payment).'
content:
application/json:
schema:
type: object
required:
- error
additionalProperties: false
properties:
error:
type: object
required:
- code
- message
properties:
code:
type: string
message:
type: string
details: {}
'409':
description: MPP challenge already used or processing. Do not authorize a duplicate payment.
'422':
description: UNSUPPORTED or INDETERMINATE. Not charged.
content:
application/json:
schema:
type: object
required:
- error
additionalProperties: false
properties:
error:
type: object
required:
- code
- message
properties:
code:
type: string
message:
type: string
details: {}
'429':
description: RATE_LIMITED
content:
application/json:
schema:
type: object
required:
- error
additionalProperties: false
properties:
error:
type: object
required:
- code
- message
properties:
code:
type: string
message:
type: string
details: {}
'502':
description: Upstream or facilitator unavailable
content:
application/json:
schema:
type: object
required:
- error
additionalProperties: false
properties:
error:
type: object
required:
- code
- message
properties:
code:
type: string
message:
type: string
details: {}
'503':
description: MPP settlement pending or uncertain. Reconcile the original transaction before paying again.
'504':
description: UPSTREAM_TIMEOUT
content:
application/json:
schema:
type: object
required:
- error
additionalProperties: false
properties:
error:
type: object
required:
- code
- message
properties:
code:
type: string
message:
type: string
details: {}
tags:
- Chain
x-service-info:
categories:
- base
- address
- proxy
- erc20
- erc165
- token-metadata
- balances
- denylist
- agent-safety
- x402
- mpp
- tempo
- deterministic
docs:
homepage: https://chainstate.schemasure.com
llms: https://chainstate.schemasure.com/llms.txt
apiReference: https://chainstate.schemasure.com/openapi.json
x-provenance:
method: harvested
publisher: SchemaSure
source: https://chainstate.schemasure.com/openapi.json
note: split by refine-openapis from the provider's own published document, verified by fetch (openapi/_original/*.fetch.json);
stamped by stamp-openapi-provenance.py (roadmap#793)