Ambr

getambr/site

This connects Claude to Ambr's permission and contract infrastructure for AI agents. You get tools to create authorization boundaries (spend caps, time windows, counterparty whitelists), mint Ricardian contracts as cNFTs on Base L2, and verify actions cryptographically. The dual format approach means every contract is both human-readable (Markdown/PDF for lawyers) and machine-parsable (strict JSON for agent execution), bound together by SHA-256 hash. Reach for this when you're building agents that spend money, delegate tasks to other agents, or need an auditable record of decisions that holds up outside the prompt window. Integrates with x402 for payments and A2A protocol for agent discovery.

tools: 7
transport: HTTP
last updated: Apr 21, 2026

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Install

From registry metadata

$ npx add-mcp https://getamber.dev/api/mcp --name ambr

Run in your terminal. add-mcp asks which agents to add it to (Claude Code, Codex, Cursor and more). Add -g to install it for every project.

Review the command, arguments and environment values before installing. MCP servers run with your local permissions.

Other ways

Claude Code

$ claude mcp add --transport http ambr https://getamber.dev/api/mcp

Run in your terminal. Add --scope user to make it available in every project.

Tools

Verified live · 7 tools

Verified live against the running server on Nov 6, 2026.

ambr_list_templatesList 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...

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 parameters. Call it with no arguments.

ambr_create_contractGenerate 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 o...6 params

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 o...

Parameters* required

oversight_threshold_usdnumber

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...

parameters*object

Template-specific parameters

parent_contract_hashstring

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*object

principal_walletstring

The deploying party's own wallet (0x…). Must differ from the counterparty wallet in parameters.

template*string

Template slug from ambr_list_templates

ambr_get_contractRetrieve 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, has...1 params

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, has...

Parameters* required

id*string

Contract ID (amb-YYYY-NNNN), SHA-256 hash, or UUID

ambr_get_contract_statusCheck 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 Ret...1 params

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 Ret...

Parameters* required

id*string

Contract ID (amb-YYYY-NNNN), SHA-256 hash, or UUID

ambr_verify_hashVerify 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 s...1 params

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 s...

Parameters* required

hash*string

SHA-256 hash to verify (64-character hex)

ambr_agent_handshakeInitiate 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...4 params

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...

Parameters* required

contract_id*string

Contract ID, SHA-256 hash, or UUID

intent*string

Handshake intentone of accept · reject · request_changes

messagestring

Optional note for counterparty

visibility_preferencestring

Optional visibility preference for negotiationone of private · metadata_only · public · encrypted

ambr_check_transactionCheck 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...7 params

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...

Parameters* required

actionstring

Action the agent is taking

amount*number

Payment amount

categorystring

Spending category

contract_id*string

Contract ID, SHA-256 hash, or UUID

currencystring

Payment currency, e.g. USD

period_spentnumber