Ambr
Server Details
Ricardian contracts for AI agents — dual-format, SHA-256 bound, legible by construction.
- Status
- Healthy
- Uptime
- 100.0% over the last 24 hours
- Last Tested
- Transport
- Streamable HTTP · MCP 2025-11-25
- URL
- ChatGPT
- –
- Claude
- –
TDQS
Scored across 7 tools
Each tool has a distinct primary purpose (create, get, status, verify, handshake, transaction check, list templates). There is mild overlap between ambr_get_contract and ambr_get_contract_status (both fetch by ID/hash) and between ambr_verify_hash and hash-based lookup in get_contract, but descriptions differentiate their focus (integrity check vs. amendment chain).
Every tool uses the consistent ambr_<verb>_<noun> snake_case pattern: ambr_create_contract, ambr_get_contract, ambr_list_templates, ambr_verify_hash, etc. No mixed conventions or vague verbs.
Seven tools is well-scoped for a contract management server, with each tool covering a needed operation (templates, create, read, status, verify, handshake, transaction check). Nothing feels redundant or padded.
Core lifecycle is covered (create, retrieve, status, verify, template discovery, handshake, transaction check), but notable gaps remain: there is no tool to propose amendments (deferred to a raw HTTP endpoint), no list-contracts operation, and no delete/terminate or share-management tool despite the domain emphasizing amendment chains and sharing.
Available Tools
7 toolsambr_agent_handshakeAIdempotentInspect
Initiate a handshake on a contract on behalf of your delegating principal.
Requires an API key with an active delegation (principal wallet registered via /api/v1/delegations). Records the agent's intent to accept, reject, or request changes on the contract. The principal must separately approve via wallet signature on the Reader Portal.
Args:
contract_id (string, required): Contract ID (amb-YYYY-NNNN), SHA-256 hash, or UUID
intent (string, required): "accept" | "reject" | "request_changes"
message (string, optional): Note for the counterparty
visibility_preference (string, optional): "private" | "metadata_only" | "public" | "encrypted"
Returns: Handshake status and next steps for principal approval.
Legibility: the handshake itself is auditable — delegation scope, agent identity, and principal approval are recorded alongside the contract hash.
| Name | Required | Description | Default |
|---|---|---|---|
| intent | Yes | Handshake intent | |
| message | No | Optional note for counterparty | |
| contract_id | Yes | Contract ID, SHA-256 hash, or UUID | |
| visibility_preference | No | Optional visibility preference for negotiation |
ambr_check_transactionARead-onlyIdempotentInspect
Check one payment against what an agreement allows. Advisory only: Ambr compares what you report with the agreement's terms; it does not authorize, block or see payments, and in_scope is not an approval or a guarantee.
Tests the payment against the agreement's status, validity window, currency, per-transaction limit, monthly limit, approved categories, enumerated actions and approval threshold. If the agreement was amended, the newest approved version is checked. Free: no credits are burned. Ambr does not hold funds or track spend, so the monthly limit is checked only when you pass period_spent. A rule the agreement sets no limit for comes back as not_evaluated, never as a pass. If a rule has a limit but you did not send what it needs (category, action, currency, period_spent), the verdict is "incomplete", not "in_scope". Send everything the agreement limits.
Access: a public contract is open to anyone; otherwise use the creator's API key or pass a share_token.
Args:
contract_id (string, required): Contract ID (amb-YYYY-NNNN), SHA-256 hash, or UUID
amount (number, required): payment amount, zero or more
currency (string, optional): e.g. "USD"
category (string, optional): spending category
action (string, optional): the action the agent is taking
period_spent (number, optional): already spent this month, to check the monthly limit
share_token (string, optional): share token for a private contract
Returns: verdict ("in_scope" | "out_of_scope" | "incomplete" | "needs_approval"), the per-rule checks, plain-language reasons, and the contract that was checked (contract_id, effective_contract_id, sha256_hash, reader_url).
| Name | Required | Description | Default |
|---|---|---|---|
| action | No | Action the agent is taking | |
| amount | Yes | Payment amount | |
| category | No | Spending category | |
| currency | No | Payment currency, e.g. USD | |
| contract_id | Yes | Contract ID, SHA-256 hash, or UUID | |
| share_token | No | Share token for a private contract | |
| period_spent | No | Already spent this month |
ambr_create_contractAInspect
Generate a Ricardian Contract from a template.
Creates a dual-format contract (human-readable legal text + machine-parsable JSON) using AI, linked by SHA-256 hash. The contract is stored on Ambr and accessible via the Reader Portal.
Requires a valid API key (X-API-Key header on the HTTP request) with available credits. Use ambr_list_templates first to discover templates and their required parameters.
Args:
template (string, required): Template slug (e.g. "d1-general-auth")
parameters (object, required): Template-specific parameters matching the schema
principal_declaration (object, required): { agent_id, principal_name, principal_type }
principal_wallet (string, optional): the deploying party's own wallet. It must differ from the counterparty wallet in parameters (same_wallet_both_parties otherwise); left out, the first wallet that signs fills the principal side
parent_contract_hash (string, optional): SHA-256 hash of a contract you created, which this one is created under (its oversight threshold then applies). Not for amendments: propose those with POST /api/v1/contracts/{id}/amend
oversight_threshold_usd (number, optional): spending level above which work created under this contract needs human approval. Children exceeding it halt at awaiting_principal_approval.
Returns:
contract_id: Unique ID (e.g. "amb-2026-0042")
sha256_hash: SHA-256 hash for verification
status: Contract status
reader_url: URL to view in Reader Portal
credits_remaining: Remaining API credits
Legibility: Output is dual-format by construction and replayable to the original SHA-256 hash — the basis of Ambr's legibility guarantee.
| Name | Required | Description | Default |
|---|---|---|---|
| template | Yes | Template slug from ambr_list_templates | |
| parameters | Yes | Template-specific parameters | |
| principal_wallet | No | The deploying party's own wallet (0x…). Must differ from the counterparty wallet in parameters. | |
| parent_contract_hash | No | SHA-256 hash of a contract you created, which this one is created under. Amendments are proposed with POST /api/v1/contracts/{id}/amend, not here. | |
| principal_declaration | Yes | ||
| oversight_threshold_usd | No | Spending level above which work created UNDER this contract requires human approval. A child contract exceeding the parent threshold is held at awaiting_principal_approval until a human signs, and cannot be signed or activated before then (EU AI Act Art. 14). |
ambr_get_contractARead-onlyIdempotentInspect
Retrieve a contract by ID, SHA-256 hash, or UUID.
With a valid API key (contract creator): returns the full contract including human-readable text, machine-readable JSON, status, and principal declaration. Without authentication: returns metadata only (contract_id, status, hash, dates).
Supports three lookup formats:
Contract ID: "amb-2026-0042"
SHA-256 hash: 64-character hex string
UUID: Standard UUID format
Args:
id (string, required): Contract ID, SHA-256 hash, or UUID
Returns: Full contract (if authorized) or metadata-only response.
Legibility: retrieval preserves the dual-format pairing — prose and JSON always replay to the same SHA-256.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Contract ID (amb-YYYY-NNNN), SHA-256 hash, or UUID |
ambr_get_contract_statusARead-onlyIdempotentInspect
Check the status of a contract and its amendment chain.
Returns the current status and any linked amendments (parent or child contracts). Useful for verifying if a contract is active, amended, or terminated.
Args:
id (string, required): Contract ID, SHA-256 hash, or UUID
Returns:
contract_id, status, created_at
amendment_type, parent_contract_hash
amendments: Array of child contracts (if any)
Legibility: amendments are bilateral and themselves dual-format — the chain stays legible from original through every revision.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | Contract ID (amb-YYYY-NNNN), SHA-256 hash, or UUID |
ambr_list_templatesARead-onlyIdempotentInspect
List available contract templates on Ambr.
Returns all active Ricardian Contract templates with their slugs, names, descriptions, categories, parameter schemas, and pricing. Use this to discover which templates are available before creating a contract with ambr_create_contract.
No authentication required.
Returns: Array of template objects with slug, name, description, category, parameter_schema, price_cents, and version fields.
Legibility: templates are the parameter schema for the dual-format contracts you create — starting here keeps your request conformant and your output defensible.
| Name | Required | Description | Default |
|---|---|---|---|
No parameters | |||
ambr_verify_hashARead-onlyIdempotentInspect
Verify a contract's SHA-256 hash to confirm document integrity.
Checks whether the provided hash matches a contract stored on Ambr. Returns verification status, contract metadata, and Reader Portal URL if found.
Args:
hash (string, required): SHA-256 hash (64-character hex string)
Returns:
verified: boolean
contract_id: string (if found)
status: string (if found)
reader_url: string (if found)
Legibility: verification is the point at which legibility becomes provable — matching hash means the prose a human reads and the JSON a machine parses are the same document that was originally signed.
| Name | Required | Description | Default |
|---|---|---|---|
| hash | Yes | SHA-256 hash to verify (64-character hex) |
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
1 tool update
- Added
ambr_check_transaction
1 tool update
- Changed
ambr_create_contract2 fields changed- removed
Input schema / properties / amendment_typeRemoved value: -{ - "enum": [ - "original", - "amendment", - "extension" - ], - "type": "string" -} - changed
Input schema / properties / parent_contract_hash / descriptionPrevious value: -"SHA-256 hash of parent contract (for amendments)"New value: +"SHA-256 hash of a contract you created, which this one is created under. Amendments are proposed with POST /api/v1/contracts/{id}/amend, not here."
1 tool update
- Changed
ambr_create_contract1 field changed- added
Input schema / properties / principal_walletAdded value: +{ + "description": "The deploying party's own wallet (0x…). Must differ from the counterparty wallet in parameters.", + "type": "string" +}
1 tool update
- Changed
ambr_create_contract1 field changed- added
Input schema / properties / oversight_threshold_usdAdded value: +{ + "description": "Spending level above which work created UNDER this contract requires human approval. A child contract exceeding the parent threshold is held at awaiting_principal_approval until a human signs, and cannot be signed or activated before then (EU AI Act Art. 14).", + "type": "number" +}
6 tool updates
- First observed
ambr_agent_handshake - First observed
ambr_create_contract - First observed
ambr_get_contract - First observed
ambr_get_contract_status - First observed
ambr_list_templates - First observed
ambr_verify_hash
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