Ambr
REMOTE · GETAMBER.DEV
Ricardian contracts for AI agents — dual-format, SHA-256 bound, legible by construction.
Available components
Last scanned (1 hour ago)
Scores higher than 91% of remote servers
Reachable. Last reached 5 Nov 2026.
Category Documents and Files
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security80
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one. See how to fix → View diagnostics → Partial
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- The HSTS (Strict-Transport-Security) header is present. View diagnostics → Pass
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability64
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 1923 tokens (~274/item across 7 items; 7 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management100
- No destabilizing schema changes in the last 30 days.Pass
Tool Coverage98
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 95% of tool parameters carry a description.Partial
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 7 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 7 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 5 Nov 26 0
- Tool “ambr_create_contract” rewrote its description, which is the text the model reads security
- Schema quality: 234 → 274 ▼ functional
- Tool coverage: 86% → 95% ▲ functional
- New tool “ambr_check_transaction” functional
- “ambr_create_contract” reworded the description of “parent_contract_hash” cosmetic
- “ambr_create_contract” dropped the optional parameter “amendment_type” cosmetic
- 27 Oct 26 0
- Tool “ambr_create_contract” rewrote its description, which is the text the model reads security
- “ambr_create_contract” added an optional parameter “principal_wallet” cosmetic
- 28 Sept 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 25 Sept 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 4 Sept 26 0
- Stability: 0.97 → pass security
- 3 Sept 26 0
- Stability: pass → 0.97 functional
- 26 Aug 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 25 Aug 26 0
- Stability: 0.97 → pass security
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 5 Nov 2026 · Probed https://getamber.dev/api/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=getamber.dev | CN=YR2,O=Let's Encrypt,C=US | 5 Sept 2026 | 4 Dec 2026 | RSA 2048 | SHA256-RSA | 5ca8cbafe07ac18db779e3f8c98a2a09c98 |
| SANs: getamber.dev | ||||||
| CN=YR2,O=Let's Encrypt,C=US (CA) | CN=Root YR,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | RSA 2048 | SHA256-RSA | 4ebd24947e24d394802d84a52fd5b319 |
| CN=Root YR,O=ISRG,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | RSA 4096 | SHA256-RSA | f24b6d17f9d9ad7cb1c9fea78782699f |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of getamber.dev. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| dev. | present | 60074 | 8 | Verified |
| getamber.dev. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
| Header | Value |
|---|---|
| strict-transport-security | max-age=63072000 |
| x-content-type-options | nosniff |
| x-frame-options | DENY |
| referrer-policy | strict-origin-when-cross-origin |
| permissions-policy | camera=(), microphone=(), geolocation=() |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://getamber.dev/api/mcp | Verified | 200 | |
| http (plaintext) | http://getamber.dev/api/mcp | HTTPS enforced | 308 | https://getamber.dev/api/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
ambr_agent_handshake ~258
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 | Type | Req | Description |
|---|---|---|---|
| contract_id | string | yes | Contract ID, SHA-256 hash, or UUID |
| intent | string | yes | Handshake intent |
| message | string | – | Optional note for counterparty |
| visibility_preference | string | – | Optional visibility preference for negotiation |
No output schema declared.
No examples provided.
ambr_check_transaction ~487
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 | Type | Req | Description |
|---|---|---|---|
| action | string | – | Action the agent is taking |
| amount | number | yes | Payment amount |
| category | string | – | Spending category |
| contract_id | string | yes | Contract ID, SHA-256 hash, or UUID |
| currency | string | – | Payment currency, e.g. USD |
| period_spent | number | – | Already spent this month |
| share_token | string | – | Share token for a private contract |
No output schema declared.
No examples provided.
ambr_create_contract ~555
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 | Type | Req | Description |
|---|---|---|---|
| oversight_threshold_usd | number | – | 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 ca… |
| parameters | object | yes | Template-specific parameters |
| parent_contract_hash | string | – | 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 | yes | – |
| principal_wallet | string | – | The deploying party's own wallet (0x…). Must differ from the counterparty wallet in parameters. |
| template | string | yes | Template slug from ambr_list_templates |
No output schema declared.
No examples provided.
ambr_get_contract ~189
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 | Type | Req | Description |
|---|---|---|---|
| id | string | yes | Contract ID (amb-YYYY-NNNN), SHA-256 hash, or UUID |
No output schema declared.
No examples provided.
ambr_get_contract_status ~150
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 | Type | Req | Description |
|---|---|---|---|
| id | string | yes | Contract ID (amb-YYYY-NNNN), SHA-256 hash, or UUID |
No output schema declared.
No examples provided.
ambr_list_templates ~121
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.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
ambr_verify_hash ~163
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 | Type | Req | Description |
|---|---|---|---|
| hash | string | yes | SHA-256 hash to verify (64-character hex) |
No output schema declared.
No examples provided.
How do I install the Ambr MCP server?
Ambr is a hosted endpoint at https://getamber.dev/api/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · getamber.dev
claude mcp add --transport http getambr-ambr-mcp-server 'https://getamber.dev/api/mcp'
What is the Ambr MCP server?
Ambr is an MCP server listed in the public MCP registry as io.github.getambr/ambr-mcp-server. Ricardian contracts for AI agents, dual-format, SHA-256 bound, legible by construction. This page covers its hosted endpoint (https://getamber.dev/api/mcp).
Is the Ambr MCP server safe to use?
Ambr scores 85 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Ambr MCP server expose?
Ambr exposes 7 tools: ambr_list_templates, ambr_create_contract, ambr_get_contract, ambr_get_contract_status, ambr_verify_hash, and 2 more. Their descriptions and schemas cost roughly 1,923 tokens of context every time the server is loaded.
Does the Ambr MCP server require authentication?
No. We connected to Ambr without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the Ambr MCP server still maintained?
Ambr is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.