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Clocktower API Terms of Use

Last updated: September 2, 2026

These Terms of Use ("Terms") govern access to the hosted Clocktower API and MCP services operated by Clocktower LLC ("Clocktower", "we", "us"). They apply to use of:

  • https://api.clocktower.finance — REST API
  • https://mcp.clocktower.finance — Model Context Protocol (MCP) server

By calling these endpoints, you agree to these Terms. If you do not agree, do not use the hosted services.

The same text is kept in the API repository TERMS.md.

1. Relationship to the open-source repository​

The source code for this implementation is published in the clocktower-protocol/api repository under the MIT License for transparency and auditability.

These Terms apply only to Clocktower's hosted API and MCP services. They do not restrict your rights under the MIT License to use, modify, or self-host the software independently. Self-hosted deployments are not supported or endorsed by Clocktower.

The official hosted API is the service above. Documentation may reference legacy *.workers.dev paths for local development and staging; those are not the production product unless we explicitly say otherwise.

2. The service​

Clocktower provides read access to Clocktower Protocol data and prepare-only write helpers (unsigned calldata) for protocol operations.

  • REST defaults to Base (chain ID 8453). Protocol routes may accept optional ?chainId= (decimal or CAIP-2) for REST-enabled chains listed in GET /catalog. Omitted chainId uses the server default (currently 8453).
  • MCP protocol tools may accept optional chainId (decimal, CAIP-2, or JSON number) for MCP-enabled chains listed in GET /catalog / list_chains. Omitted MCP chainId uses Base (8453) and does not follow the REST default. SIWE and Builder entitlement (when that lane is enabled) stay on Base. x402 on MCP, when enabled, is also Base-only.
  • The server does not custody user keys, relay signed transactions, or broadcast transactions on your behalf. You sign and submit from your own wallet.
  • Subscription amount values on API inputs are human token-unit strings (for example "10" or "100.5"), not protocol wei.
  • Live routes, chain registry, and rate limits are in GET /catalog. Catalog values control what is actually enabled.

We may add, change, or remove endpoints, chains, limits, or features at any time.

See REST authentication, REST chain selection, MCP chain selection, and MCP connection.

3. Access tiers and authentication​

Successful REST responses include an X-Clocktower-Lane header (free, developer, or builder when that lane is enabled).

Free REST tier​

  • No account or API key required.
  • Limits are per IP (request rate, expensive-route rate, subgraph daily, prepare/readiness RPM and daily, and a daily request total).
  • Search and similar discovery calls are capped (including first and includeDetails).
  • Cross-account reads and prepare endpoints are allowed within those limits.
  • On-chain authorization still applies to any transaction you sign and broadcast.

Developer REST tier (API keys)​

  • Authenticate with Authorization: Bearer ctk_….
  • Keys are free. They raise read limits (per key id, not IP). Prepare/readiness stays intentionally tight because full prepare runs on-chain simulation and gas estimation on shared RPC.
  • Keys are issued via Clocktower's developer portal or an admin mint path. The plaintext token is shown once at creation. Clocktower stores a SHA-256 hash of the key, not the plaintext.
  • Invalid, unknown, or revoked keys return 401. They do not fall back to the free tier.
  • Do not share, sell, or transfer keys. Do not embed long-lived ctk_… keys in public client-side applications.
  • The same developer key authenticates MCP when sent as Authorization: Bearer ctk_… on the MCP connection.

Builder REST tier (optional; may be off)​

  • Builder is an optional higher REST lane. It is disabled unless Clocktower configures on-chain entitlement subscription ID(s). Check builderAuthEnabled on GET /catalog.
  • When enabled, access requires an ACTIVE entitlement subscription on Base and a valid SIWE session (Authorization: Bearer cts_…). Entitlement is always evaluated on Base, even if the REST call uses another chainId.
  • Access is wallet-scoped (including :me routes where offered). Sessions expire and may be revoked if entitlement lapses.
  • Do not share, sell, or transfer session tokens.

MCP (agents)​

  • Uses the same free (per IP) and developer (ctk_…) lanes as REST. Each tool call counts against those rate limits.
  • Optional: send Authorization: Bearer ctk_… in the MCP client headers for the developer lane.
  • Invalid or revoked keys fail the request. They do not fall back to the free tier.
  • Builder SIWE sessions (cts_…) are REST credentials, not MCP credentials.

You must not circumvent tier restrictions (rate limits or entitlement checks).

4. Acceptable use​

You agree not to:

  • Abuse rate limits, scrape at scale, or use the API in a way that degrades the service for others
  • Bypass authentication, geo-restrictions, or rate limits
  • Probe or attack the service (DDoS, credential stuffing, injection attempts, etc.)
  • Mine or farm prepare/readiness as a substitute for your own RPC
  • Misrepresent affiliation with Clocktower
  • Use the API for unlawful activity or to violate third-party rights
  • Resell or repackage the hosted API as a competing commercial service without our written permission

We may throttle, challenge, suspend, or block access (by IP, address, API key, session, or other signal) at our discretion.

For production write volume, use your own RPC (and, when available, the Clocktower SDK) rather than exhausting hosted prepare quotas.

5. Prepare endpoints and on-chain actions​

Write endpoints and MCP write tools return unsigned transactions and/or readiness information. You are solely responsible for reviewing, signing, and broadcasting transactions from your wallet. Clocktower does not custody keys, broadcast on your behalf, or guarantee that a prepare response will succeed on-chain.

Simulation, gas estimates, and subgraph data are advisory. Chain state, mempool conditions, and RPC latency can change before broadcast.

When you already have a subscription id, prefer the *_by_id prepare and readiness paths. Amount, token, and provider are loaded from chain.

See write endpoints and the MCP write workflow.

6. Data accuracy and third-party services​

The API reads on-chain data via RPC providers (for example Alchemy) and, for some routes, The Graph subgraphs. We strive for accuracy but do not warrant that responses are complete, current, or error-free. Subgraph rows may lag or disagree with chain state.

Do not rely on the API as the sole source of truth for financial or legal decisions. Verify critical values on-chain.

7. Fees and payments​

  • REST and MCP (free and developer): No usage fee. Access is rate-limited. Developer keys are issued without a Clocktower usage fee.
  • Builder entitlement (when enabled): On-chain subscription fees to Clocktower LLC are separate from API usage and are governed by the Clocktower Protocol smart contracts.
  • Gas: You pay network gas for any transaction you broadcast.

Fees are non-refundable except where required by law.

8. Availability and changes​

The service is provided on a best-effort basis. We do not guarantee uptime, latency, or continued availability of any endpoint. We may:

  • Enable maintenance mode (API_ENABLED=false or equivalent) for REST without taking MCP down
  • Change rate limits or tier rules
  • Modify or discontinue endpoints or chains

Material changes to these Terms will be reflected here and in the API repository TERMS.md with an updated "Last updated" date. Continued use after changes constitutes acceptance.

9. Geographic restrictions​

Access may be restricted in certain jurisdictions (including where required by law or policy). The service may block requests identified as originating from restricted regions (including New York State, USA, as implemented in the Worker).

10. Privacy​

We process request metadata to operate, rate-limit, and secure the service, including:

  • IP address and Cloudflare edge geo signals
  • Wallet addresses and other identifiers you send in requests
  • Route, method, status, and access lane
  • Developer key id (not the full ctk_… secret)
  • Rate-limit identity and aggregate usage metrics (including Analytics Engine)

We do not log or store the plaintext API key after issuance. Keep tokens confidential. Do not send secrets in API bodies.

We do not publish a separate privacy policy in the API repository; contact us for privacy questions.

11. Disclaimers​

THE HOSTED API AND MCP SERVICES ARE PROVIDED "AS IS" AND "AS AVAILABLE" WITHOUT WARRANTIES OF ANY KIND, WHETHER EXPRESS OR IMPLIED, INCLUDING MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.

CLOCKTOWER DOES NOT WARRANT THAT THE SERVICE WILL BE UNINTERRUPTED, SECURE, OR ERROR-FREE, OR THAT ON-CHAIN OR SUBGRAPH DATA IS ACCURATE.

12. Limitation of liability​

TO THE MAXIMUM EXTENT PERMITTED BY LAW, CLOCKTOWER LLC AND ITS AFFILIATES, OFFICERS, AND CONTRIBUTORS WILL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES, OR ANY LOSS OF PROFITS, DATA, OR GOODWILL, ARISING FROM YOUR USE OF THE HOSTED SERVICES.

OUR TOTAL LIABILITY FOR ANY CLAIM ARISING FROM THESE TERMS OR THE SERVICE IS LIMITED TO USD $100.

Some jurisdictions do not allow certain limitations; in those cases, our liability is limited to the fullest extent permitted by law.

13. Indemnity​

You agree to indemnify and hold harmless Clocktower from claims, damages, and expenses (including reasonable legal fees) arising from your use of the hosted services, your on-chain transactions, or your violation of these Terms.

14. Termination​

We may suspend or terminate your access at any time, with or without notice, for violation of these Terms or for operational or legal reasons. Provisions that by their nature should survive (disclaimers, liability limits, indemnity) survive termination.

15. Governing law​

These Terms are governed by the laws of the jurisdiction in which Clocktower LLC is organized, without regard to conflict-of-law principles, except where mandatory consumer or data-protection rules in your country of residence apply and cannot be waived by contract.

16. Contact​

Questions about these Terms or the hosted API: