airSlate SignNow

# Fix list: airSlate SignNow

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/signnow, the October 2026 research run, assessed 7 October 2026. Grade B, 68.5 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 airSlate SignNow: 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. Payments & pricing, 35 out of 100, up to 8.1 more on the total

Why it scored 35: No x402, MPP or L402 found (0). The developers page states per-invite prices, from $2 at 500 invites to $1.20 at 5,000. The full plan table is a JavaScript page we couldn't read, so we scored between plan-only and per-unit (15). Development mode is free with up to 500 invites, and the help centre says the free trial needs no credit card (20). A person has to register in a browser and verify an email address before the first key exists (0).

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.

## 2. Security & auth, 62 out of 100, up to 6.7 more on the total

Why it scored 62: OAuth 2.0 with password, refresh and authorisation code grants and a `scope` parameter that limits a token to URL patterns. API keys can be deleted but don't expire and work for all API requests, and the hosted MCP server adds OAuth with PKCE (24). We deducted 5 of the possible 10 for secrets in URLs, because embedded links returned by the API carry an `access_token` query parameter, with a 15 to 45 minute expiry on embedded sending links (19). A URL-pattern scope allows a read-only token, the hosted MCP grant covers documents and templates only, and the bundled skill tells agents to wait for confirmation before sending. Nothing enforces that confirmation (12). The API returns document text and field values written by signers, and no prompt-injection guidance was found (3). The API dashboard logs every request and webhook delivery, and documents carry a full history endpoint (13). SOC 2 Type II, PCI DSS and HIPAA per the security page and a HackerOne bug bounty by invitation. security.txt returns 404, and the MCP repository's SECURITY.md still has a placeholder contact (15).

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.

## 3. Agent ergonomics, 66 out of 100, up to 5.5 more on the total

Why it scored 66: Graded on the REST API, with the MCP server noted. List endpoints take page and per_page or limit and offset, with no field selection found. The MCP server loads 20 documented tools, 21 in the v3.1.0 source (15). Pagination, filters and sorting exist but in several parameter styles (`filter:type`, `filters[...]`, `sort:created`, `sort_by`) (15). Errors come as a JSON code and message with a troubleshooting page, but code 65582 covers many causes and the docs tell callers to read the message text (13). No idempotency key on the API. The MCP tools set readOnlyHint, destructiveHint and idempotentHint (8). SDKs for PHP, Node, Python, .NET and Java, and an API key works with one header (15).

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.

## 4. Schema & documentation, 81 out of 100, up to 3.1 more on the total

Why it scored 81: Graded on the REST API, with the MCP server noted. OpenAPI 3.0.3 and Swagger 2.0 are public, with 226 paths and 354 operations (25). docs.signnow.com/llms.txt indexes a Markdown copy of every page, with llms-full.txt (10). All 354 operations have a description and the MCP tool descriptions say what to call next, but the API reference rarely says when not to use an endpoint (14). The spec marks required fields often but holds only 29 enums across 354 operations (9). 342 operations have examples and there is an API errors page, though numeric codes aren't unique (12). The changelog is dated by month back to February 2025. The spec version stays at 1.0.0 and paths mix unversioned and /v2 routes (11).

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.

## 5. Maintenance & community, 72 out of 100, up to 2.5 more on the total

Why it scored 72: The API changelog's newest entry is September 2026, dated by month only, and the PHP SDK v3.5.4 shipped on 3 September 2026, 34 days before this check. We scored between the 30-day and 90-day bands (25). The changelog has entries for July, August and September 2026 (20). Closed service with a monthly changelog and API support at api@signnow.com. The MCP repository that the docs name for issue reports is archived (8). SDKs for five languages are current, with PHP in September 2026, Python in April and Node in March. The official MCP registry lists io.github.signnow/sn-mcp-server at 0.3.1 while PyPI has 3.1.0 (13). The MCP repository has CI with ruff, mypy and pytest and 60 test files, and it is archived (6).

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. Transparency & trust, 74 out of 100, up to 2.3 more on the total

Made of editorial 62, provenance 86.

Why it scored 74: Closed service with public terms last updated 2 March 2023, and MIT licences on the MCP server and SDKs (17). The DPA of 1 July 2025 promises deletion or return of customer personal data within 30 days on request after the service ends. The privacy notice of 12 August 2026 gives no retention periods and says usage analysis includes training AI models, while the MCP security page says MCP data is never used for training (20). No deprecation policy was found. The terms say material changes take effect at the next subscription period, and the changelog mentions retired settings without dates (5). The subprocessor list of 18 September 2026 names each subprocessor with its country, with AWS in the United States, Germany and Australia (20).

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 7 of the 7 things a reader expects, and has 2 clauses that cost points (6 of 10)
- security.txt: not found (0 of 10)

## 7. Reliability, 93 out of 100, up to 1.4 more on the total

Why it scored 93: Graded as a hosted API. Statuspage at status.signnow.com with six components including API (20). The incident feed shows one incident in the last 90 days, a minor one on 3 September 2026 that made the SignNow University site unavailable for eight minutes, and none on the API component (30). Limits are published with numbers, 500 requests an hour in Development and 1,000 in Live (15). 429 is documented with X-RateLimit-Limit, Remaining and Reset headers and advice to back off exponentially. No Retry-After header and no idempotency key were found, and sending an invite is a charged write (8). The SLA commits to commercially reasonable efforts for 99.9 per cent monthly uptime with credits of 10 or 30 per cent (10). The REST API is generally available (10).

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.

## Deductions

Each comes off the total. A fixed and documented problem counts for less at the next check.

- Until release v2.7.0 on 8 July 2026 the MCP server's signing links carried the user's raw SignNow access token in the URL query string. The fix and a regression test are documented in the pull request, so we deducted 2 (https://github.com/signnow/sn-mcp-server/pull/65).

## 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.

- unchecked: the API plan table at snseats.signnow.com/purchase/api/pricing (JavaScript-only page). Prices come from the developers page
- unchecked: whether the API free trial asks for a card. The help centre says the free trial needs no credit card, without naming the API trial
- Why the sn-mcp-server GitHub repository is archived and whether the hosted server at mcp-server.signnow.com is still developed elsewhere. The README and docs carry no notice
- unchecked: the hosted MCP server's live tool list, which needs an OAuth sign-in. The count comes from the docs (20) and the v3.1.0 source (21)
- Whether the access_token in embedded link URLs is a short-lived link token or the caller's own token
- Access-token lifetime. The auth guide's examples show `expires_in` as 2592000 in one response and a timestamp in another
- Whether SignNow holds ISO 27001. The security page doesn't list it
- unchecked: the help centre article on AI data use (helpcenter.signnow.com), which the MCP security page cites

## Weaknesses

- API keys don't expire and work for all API requests. Narrower access needs an OAuth token requested with a URL-pattern scope
- No idempotency key was found in the spec or guides, and each signature invite sent is charged
- The sn-mcp-server GitHub repository was archived when checked on 7 October 2026, while the docs still send issue reports there
- Numeric error codes aren't unique. The docs tell callers to identify a problem by its message text
- The API plan table is a JavaScript page we couldn't read. Only the per-invite range on the developers page is public text

## 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 https://api.signnow.com with `Authorization: Bearer <API key or access token>`. Development and Live share this host, and Development documents carry a watermark
- Request OAuth tokens with a narrow `scope` such as `document/* GET/user`. The default `*` grants every API action
- Read `X-RateLimit-Remaining` and `X-RateLimit-Reset` on each response. The limit is 500 requests an hour in Development and 1,000 in Live, and 429 has no Retry-After
- Check invite status before resending. No idempotency key exists, and a repeated invite call counts as another charged invite
- Set `secret_key` when creating an event subscription and verify `X-SignNow-Signature` (HMAC SHA-256 of the body) on every callback

## 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.