Zernio (formerly Late) API + MCP by Zernio

# Fix list: Zernio (formerly Late) API + MCP

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/late, the October 2026 research run, assessed 1 October 2026. Grade B, 67.5 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 Zernio (formerly Late) API + MCP: 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, 57 out of 100, up to 7.5 more on the total

Why it scored 57: API keys as Bearer tokens, restricted keys created through POST /v1/api-keys with any of ten resource groups switched off, and OAuth 2.1 with dynamic client registration on the MCP with eight scopes such as posts:read and analytics:read (30). Read-only keys and scopes are possible and tools are annotated, but we found no approval guidance for publishing (14). The inbox, comments and DM tools return text from strangers and we found no prompt-injection guidance (0). X-Request-Id on every response, no audit log found (3). The pricing page and privacy policy point to a trust portal with SOC 2 and GDPR paperwork. No security.txt, and the privacy contact is a named person's email (10).

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. Payments & pricing, 40 out of 100, up to 7.5 more on the total

Why it scored 40: No x402 or other machine payment (0). Per-unit prices published without login, per connected account a month, X calls passed through at X's rates and SMS per message (20). Two accounts free with no card (20). A person signs up in a browser for the first key. Keys can then be minted by API, which doesn't remove the human step (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.

## 3. Reliability, 80 out of 100, up to 4 more on the total

Why it scored 80: Better Stack page at zernio-status.com with components for the API, each network, schedulers, webhooks, inbox and analytics (20). Four incidents since July, all degraded rather than down and none over 1 hour 15 minutes, the longest being Google Business image posts failing on 30 September (20). Limits published by tier, 60, 600 or 1,200 requests a minute, a per-second analytics window and per-network posting caps (15). 429 carries Retry-After and X-RateLimit headers, and an Idempotency-Key covers posts and other writes (15). The terms state no SLA (0). GA (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.

## 4. Transparency & trust, 59 out of 100, up to 3.6 more on the total

Made of editorial 40, provenance 78.

Why it scored 59: Closed API under published terms, with the Node SDK under Apache-2.0 (15). Privacy policy updated 1 October 2026 deletes data within 30 days of account deletion and says content reached through the MCP or API isn't used to train models, but names no subprocessors and links no DPA (16). No deprecation policy. Breaking changes ship on the day marked BREAKING, and old getlate.dev URLs still redirect (6). No subprocessor list or data locations found (3).

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):

- Domain age: zernio.com, registered 2025-08-14 (1 year) (3 of 15)
- security.txt: not found (0 of 10)

## 5. Schema & documentation, 83 out of 100, up to 2.8 more on the total

Why it scored 83: OpenAPI 3.1 at zernio.com/openapi.yaml, API version 1.194.0, over 200 paths (25). llms.txt and Markdown pages (10). The MCP has a docs_search tool and annotated tools. We didn't read tool descriptions in source (12). Inputs typed in the spec with resource groups and enums (12). A shared ErrorResponse with a machine code and message, X-Request-Id on responses, examples on operations (12). Dated public changelog and a changelog API, but breaking changes ship inside v1 (12).

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.

## 6. Agent ergonomics, 88 out of 100, up to 2 more on the total

Why it scored 88: The tools page lists 20 core tools and says tools/list returns about 50 everyday ones, with search_tools and call_tool loading the long tail on demand (5 plus 10). Page and cursor pagination on list endpoints (20). ErrorResponse codes such as idempotency_conflict, and the MCP returns the list of accounts when account_id is ambiguous (18). Idempotency-Key with 24-hour keys and an Idempotent-Replayed header, plus readOnlyHint, destructiveHint and openWorldHint on tools (20). Node and Python SDKs (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.

## 7. Maintenance & community, 87 out of 100, up to 1.1 more on the total

Why it scored 87: @zernio/node 0.2.1056 published on 1 October 2026 and changelog entries the same day (30). Dozens of releases and changelog entries in the last 90 days (20). Public changelog and support. The SDK repo is generated, so issue replies weren't a useful signal (12). Official registry entry com.zernio/zernio under its own domain, per the 30 September check (15). The Node SDK runs ci, generate and publish workflows and regenerates from the OpenAPI spec several times a day (10).

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.

## Deductions

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

- 2026-09-29 to 2026-10-01. The changelog marks several changes BREAKING on the day they shipped, with no notice period. Timestamps without an offset now follow the profile timezone instead of UTC (29 September), accountId is required to edit or unpublish a multi-account post (30 September), and LinkedIn multi-account connect needs selections instead of accountType (1 October). We count the label as disclosure but not notice. -4 (https://docs.zernio.com/changelog)

## 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 an analytics add-on is still needed for follower data. The pricing page says every feature is on every tier
- unchecked: MCP tool descriptions in source, and the exact number tools/list returns (the docs say 20 core tools and about 50 everyday ones)
- Whether customers got any notice of the 29 September timezone change before it shipped
- unchecked: the content of the trust portal at trust.zernio.com

## Weaknesses

- Several breaking changes shipped between 29 September and 1 October 2026 with no notice period
- Reddit and TikTok posting budgets are shared across all Zernio customers
- SDKs are pre-1.0 (0.2.1056) and release many times a day
- No security.txt, no subprocessor list and no DPA linked from the privacy policy
- Renamed from Late in 2026, so docs and packages exist under both names

## 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.

- Send an Idempotency-Key (a fresh UUID per post) on POST /v1/posts and reuse it only on a retry
- Give timestamps an explicit offset, because times without one now follow the profile timezone rather than UTC
- Pass accountId when editing or unpublishing a post that targets several accounts
- Wait Retry-After on 429. Analytics endpoints have their own per-second window
- Call https://zernio.com/api/v1, not the old getlate.dev base, and pin the SDK version

## What the review panel asked for

- Notice period before BREAKING
- Per-customer network budgets
- publish a security.txt
- inbox injection guidance

## 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.