Acuity Scheduling API

# Fix list: Acuity Scheduling API

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/acuity-scheduling, the October 2026 research run, assessed 8 October 2026. Grade E, 42.4 out of 100.

This is everything the published grade says the listing lacks, the biggest possible gain to the total first. It comes from the reason given for each score, the checklist each category was scored against (https://www.anchorterminal.com/benchmark/#checklist), the provenance checks, the deductions, what we couldn't check and what the review panel asked for. A fix counts at the next check, once it's public.

For a coding agent working on Acuity Scheduling API: work through the items below in the product, its docs and its public pages. Each category gives the reason for its score, with the points each checklist item earned, and the checklist itself, so the gap is the items that earned less than their points. Change the product, not the wording, and keep a note of what you changed and where it's published.

## 1. Security & auth, 27 out of 100, up to 12.8 more on the total

Why it scored 27: Basic authentication with one account API key, or OAuth2 with the single scope `api-v1`. Tokens can be disabled at `/oauth2/disconnect`. No scoped keys, expiry or rotation documented. Credentials travel in headers only (15). No read-only credential. Client-mode validation is the default and `admin=true` is opt-in (3). Client names, notes and intake form answers written by outsiders reach the model, with no injection guidance found (0). No API audit log found (0). Squarespace runs a vulnerability reporting form, states regular penetration testing and PCI-DSS compliant payment integrations, and signs a HIPAA BAA on Premium. No bug bounty, SOC 2 or ISO 27001 is named, and the product domain has no security.txt (9). Total 27.

The checklist (https://www.anchorterminal.com/benchmark/#checklist-security):

- 0 to 30, the credential model. 30 for OAuth 2.1 with scopes, or scoped and revocable keys with rotation. 20 for plain revocable API keys. 10 for one all-powerful key. 10 off when a secret can travel in a URL query string as a documented option.
- 0 to 20, read-only or least-privilege modes, and confirmation or approval for destructive actions.
- 0 to 15, prompt-injection posture where the tool returns untrusted content (documented mitigations or guidance). A tool that returns no untrusted content gets 10.
- 0 to 15, audit logs or per-call visibility for the operator.
- 0 to 20, a security programme. security.txt or a disclosure policy, a bug bounty, SOC 2 or ISO 27001, advisories handled in public.

Models are read for retention, whether API data trains models (and whether that's off by default), zero-retention options and certifications. Frameworks for telemetry defaults, approval hooks, guardrails and sandboxing.

## 2. Agent ergonomics, 44 out of 100, up to 9.1 more on the total

Why it scored 44: `max` caps list size and `excludeForms` trims intake forms from appointments. No field selection (10). Filters by date, calendar, type and client, but no cursor or offset is documented, so long lists need date windows (10). Errors carry a status, a named code and a message, and a 404 suggests the nearest path (16). No idempotency key or safe-retry guidance for `POST /appointments` (0). Booking needs five fields and picks a calendar when none is given. SDKs exist for Node.js and PHP, both last released in 2019 (8). Total 44.

The checklist (https://www.anchorterminal.com/benchmark/#checklist-ergonomics):

- 0 to 25, context cost. For MCP, the number and size of the tool definitions (25 for ten or fewer compact tools, 15 for 11 to 30, 5 for more than 30, plus up to 10 back for toolsets, dynamic loading or read-only subsets). For APIs, whether responses can be sized (field selection, limits, summaries).
- 20, pagination, filtering and output-size controls.
- 20, actionable, documented error responses, codes and messages an agent can recover from.
- 20, idempotency or safe retries, and for MCP the `readOnlyHint` and `destructiveHint` annotations.
- 15, sensible defaults, few required parameters, and official SDKs in at least two languages.

Models are read for tool use, structured output, prompt caching, context length, batch and SDKs. Frameworks for how much code and how many defaults a tool-calling agent with MCP needs.

## 3. Payments & pricing, 30 out of 100, up to 8.8 more on the total

Why it scored 30: No x402, MPP or L402 (0). Plan prices are public, $20, $34 and $61 a month, with nothing per call (10). A 7-day trial needs no card. Whether the trial includes API access was not established (20). A person signs up in a browser and copies the key or approves OAuth (0). Total 30.

The checklist (https://www.anchorterminal.com/benchmark/#checklist-payments):

The published rubric, also on the [x402 page](https://www.anchorterminal.com/x402/).

- 40, a machine payment protocol (x402, MPP or L402) on the tool's own endpoints. 10 to 30 when it covers only some endpoints or only goes through a third party, and the note says which.
- 20, per-call or per-unit pricing published without a login. 10 for public plan-only pricing, 0 for "contact sales" or prices behind a login.
- 20, a free tier or trial that doesn't need a card.
- 20, autonomous onboarding, meaning an agent can get access without a person signing up in a browser (keyless use, x402, a programmatic key API).

Payment platforms and agent wallets rarely charge for their own API over a machine protocol, so the first line has steps for them, and the highest one that applies counts. 40 when x402, MPP or L402 runs on all their own endpoints, 30 when it runs on part of their own API, 25 when their merchants can accept one, 20 for running a facilitator, 15 for paying as a buyer, and 0 when the only protocol is their own. Merchant acceptance sits above a facilitator because the platform's own customers can charge agents through it, while a facilitator settles for sellers who wire up the protocol themselves. The counter-argument (a facilitator does more for the protocol as a whole) has a point. Each note says which step applied.

Open-source software you run yourself is scored on its hosted or paid option if it has one. A free, self-hosted package with nothing to buy gets 20, 20 and 20 for the last three lines, and 0 to 40 for the first only if it ships a payment protocol.

## 4. Reliability, 58 out of 100, up to 8.4 more on the total

Why it scored 58: Graded as a hosted API. Statuspage site at status.acuityscheduling.com with incident history, though one component stands for the whole product (20). In the 90 days to 8 October 2026 the feed shows a critical disruption of 2 hours 5 minutes on 19 July and one of 18 minutes on 12 August, both marked as possibly affecting all users and services, plus a four-day iOS app fault and three minor integration incidents. Read as one major outage (10). 10 requests a second and 20 concurrent connections per IP (15). The 429 body is documented, with no `Retry-After`, backoff advice or idempotency key for booking writes (3). No SLA found, and the Developer Terms disclaim uninterrupted service (0). The v1 API is generally available (10). Total 58.

The checklist (https://www.anchorterminal.com/benchmark/#checklist-reliability):

Hosted APIs, MCP servers, models and platforms.

- 20, a public status page with component history (Statuspage, Instatus, BetterStack or the vendor's own).
- 0 to 30, the incident record for the last 90 days on that page. 30 for a clean record or trivial incidents only, 20 for minor incidents only, 10 for one major outage (an hour or more of a core API down, or errors across the board), 0 for several. 5 when there's no history we could read, and the note says so.
- 15, rate limits documented with numbers.
- 15, documented 429 or overload handling (Retry-After, backoff guidance), and idempotency keys or safe-retry guidance where writes are involved.
- 10, an SLA published for any paid tier.
- 10, the surface agents use is generally available, not beta or preview.

Local packages, SDKs, frameworks and stdio MCP servers.

- 20, installs from an official package with supported runtimes stated.
- 25, a public CI and test suite, passing on the default branch.
- 0 to 25, open crash or regression issues relative to activity (25 for few and handled, 0 for many, old and unanswered).
- 15, semver discipline and breaking changes called out in a changelog.
- 15, version 1.0 or later, or declared stable.

Protocols are read from their reference implementations, the public facilitators or servers, spec stability and test vectors.

## 5. Maintenance & community, 15 out of 100, up to 7.4 more on the total

Why it scored 15: No changelog or release notes found. The docs' own page dates show the OAuth guide edited on 1 October 2026 and the webhooks guide on 25 June 2026, which we count as the latest dated change (10). No three dated entries in 90 days (0). A developer email address and a support form, with no public issue tracker for the API (5). The Node.js and PHP SDKs were last tagged in July 2019 (0). No current package to assess (0). Total 15.

The checklist (https://www.anchorterminal.com/benchmark/#checklist-maintenance):

- 0 to 30, time since the last release, or the last published model or API change for a closed service. 30 within 30 days, 20 within 90, 10 within 180, 0 older.
- 20, at least three releases or dated changelog entries in the last 90 days.
- 0 to 25, responsiveness. Issues and pull requests answered on GitHub (the open issues and how recent the replies are). For closed services, a public changelog and a support or community channel that answers, 0 to 15.
- 15, presence in the official MCP registry under a verified namespace (MCP servers), or current official SDKs (APIs and models).
- 10, package health, current dependencies and CI.

Models are read for deprecation notice periods and model churn rather than release counts.

## 6. Schema & documentation, 56 out of 100, up to 7.2 more on the total

Why it scored 56: Each reference page carries an OpenAPI 3.1 fragment for its own operation, generated by the docs platform from hand-written pages. No single downloadable specification was found (15). `llms.txt` is published and every page has a Markdown copy, but the index lists only five of 36 reference pages (8). Pages explain client and admin booking modes and when availability is validated, without when-not-to-use guidance (10). Parameters are typed with required fields, but there are no enums and `datetime` is any string PHP's strtotime accepts (8). Request examples, an error table and per-endpoint error codes (12). The path is versioned as v1, with no changelog found (3). Total 56.

The checklist (https://www.anchorterminal.com/benchmark/#checklist-schema):

APIs and MCP servers.

- 25, a machine-readable contract (a public OpenAPI file or similar; for MCP, typed JSON Schema inputs on every tool).
- 10, llms.txt or Markdown docs served for agents.
- 0 to 20, descriptions that say what a tool is for, when to use it and when not to, read from the tool definitions in the source or the API reference.
- 0 to 15, typed inputs with enums, constraints and required fields, and no free-form JSON blobs.
- 0 to 15, examples and documented error responses.
- 15, versioning and a public changelog.

Models are read from the API reference, the OpenAPI file, llms.txt, the structured-output and tool-use docs and the model cards. Frameworks from docs a model can follow, typed interfaces, examples and the API reference.

## 7. Transparency & trust, 54 out of 100, up to 4 more on the total

Made of editorial 34, provenance 74.

Why it scored 54: Closed service under Squarespace's Developer Terms of 16 December 2025, with MIT SDKs (15). The privacy policy of 15 July 2026 names acuityscheduling.com and states no retention periods. The DPA of the same date promises deletion within 90 days of cancellation on written request (15). No deprecation policy, and the Developer Terms allow changes to developer tools without notice (0). Sub-processors are disclosed only on request by email, and data may move to any country where Squarespace or its sub-processors operate, the US in particular (4). Total 34.

The checklist (https://www.anchorterminal.com/benchmark/#checklist-transparency):

- 0 to 30, source availability and licence clarity. 30 for open source under an OSI licence, 15 for closed with clear terms, 0 for unclear terms.
- 0 to 30, data handling and retention statements that agree with each other (privacy policy, DPA, retention periods, subprocessors).
- 0 to 20, a deprecation policy or notices with dates.
- 0 to 20, telemetry disclosed with an opt-out (local software), or subprocessors and data locations disclosed (hosted).

The other half of Transparency and trust is the provenance score, computed from checked facts (below). The category score is the mean of the two.

Provenance checks not met in full (half of this category, computed from checked facts):

- Terms of service: read, states 6 of the 7 things a reader expects, and has 2 clauses that cost points (5.1 of 10)
- Privacy policy: read, states 7 of the 8 things a reader expects (9.3 of 10)
- Changelog: not found (0 of 10)
- security.txt: not found (0 of 10)

## What we couldn't check

What we couldn't read counted as absent. Publishing it on a page a plain HTTP fetch can read (not only in a browser) lets the next check count it.

- Whether the 7-day trial includes API access, given the pricing page lists the API on Premium only
- Whether the account API key can be rotated, and whether OAuth access tokens expire. The OAuth guide shows no expiry or refresh token
- Whether `GET /appointments` has any paging beyond `max` and the date filters
- Whether Squarespace holds SOC 2 or ISO 27001 reports covering Acuity. None is named on the security or measures pages
- The Squarespace DPA does not name Acuity Scheduling. It covers the Services, which the Terms of Service define to include acuityscheduling.com
- unchecked: help.acuityscheduling.com answered 403, so the help centre's articles on API credentials and plans were not read
- unchecked: Squarespace's Acceptable Use Policy, which the Terms of Service incorporate
- unchecked: the Enterprise API documented at enterprise-scheduling.readme.io, which is sold through sales and is not graded here
- unchecked: GitHub issue activity for the two SDK repositories, and star counts

## Weaknesses

- The pricing page lists custom API access on Premium only, $61 a month or $49 billed yearly
- OAuth2 has one scope, `api-v1`, and Basic authentication uses one account API key, so no read-only credential exists
- No changelog or deprecation policy was found, and the Developer Terms allow changes without notice
- The Node.js and PHP SDKs were last released in July 2019
- The status page records two critical service disruptions in the last 90 days, on 19 July and 12 August 2026

## What costs an agent a turn today

The notes we give agents before they call it. Each one is a workaround an agent shouldn't need.

- Call `/availability/dates` then `/availability/times` with `appointmentTypeID` before `POST /appointments`, which validates the slot as a client would
- Avoid `admin=true` unless the owner asks for it, because it skips availability and form validation
- Pass `noEmail=true` when a booking or cancellation must not send the client an email or SMS
- Check `GET /appointments` filtered by `email` and date before retrying a booking, since no idempotency key is documented
- Stay under 10 requests a second and 20 concurrent connections per IP, and back off on 429, which carries no documented `Retry-After`

## When it's done

Send what changed and where it's published as a dispute (https://www.anchorterminal.com/builders/#disputes, or `POST https://www.anchorterminal.com/api/v1/contact` with `"kind": "dispute"`). Disputes are answered in public, and the listing is checked again by the same checklist. Paying for an audit or a listing claim changes nothing here.