Mixpost API + MCP by Mixpost (Inovector)

# Fix list: Mixpost API + MCP

From Anchor Terminal's listing at https://www.anchorterminal.com/tools/mixpost, the October 2026 research run, assessed 1 October 2026. Grade D, 49.7 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 Mixpost 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. Payments & pricing, 10 out of 100, up to 11.3 more on the total

Why it scored 10: No x402 (0). Pro is $299 once and Enterprise $1,199 once, both public, with no per-call price (10). Lite is free but has no API or MCP, and Pro has a 14-day money-back guarantee rather than a trial (0). A person has to buy a licence and install the software (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, 43 out of 100, up to 10 more on the total

Why it scored 43: Personal access tokens as Bearer headers that expire after 7, 30, 60 or 90 days, a custom date or never, and can be deleted, but carry the full authority of the user who made them (20). A token from a Viewer-role user can only read, and Member or Admin is needed to write. No approval step (10). Tools return the operator's own posts and analytics, little untrusted text (10). No audit log found (0). SECURITY.md asks for reports by email, yet two security reports sit open in public on the Lite repo with no advisory, path traversal since 24 February 2026 and XSS since 17 June 2026. No security.txt (3).

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, 53 out of 100, up to 7.6 more on the total

Why it scored 53: 30 MCP tools with no toolsets (15). Some list endpoints paginate and some don't, per the API docs (12). Laravel-style JSON errors with field messages and 422 for validation (15). No idempotency keys, and the read, write and destructive labels live in the docs rather than as MCP annotations. unschedule-post and restore-post give safe ways back (6). No official SDKs, only an n8n community node (5).

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. Reliability, 70 out of 100, up to 6 more on the total

Why it scored 70: Scored on the checklist for software you run yourself, since Pro installs into your own Laravel app and its uptime is whatever your server gives it. Mixpost Cloud has no status page we could find. Installs from Inovector's Composer repository with PHP 8.2 or later stated (20). Lite runs a public test workflow on PHP 8.2 and 8.3, and Pro's CI isn't public (10). The Lite repo has 27 open issues, including bug reports from December 2025 to June 2026 with no maintainer replies visible, and Pro's tracker is private (10). Release notes per version, with v7.0.0 flagged as breaking (15). Past 1.0, at Pro v7.0.3 (15).

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. Transparency & trust, 51 out of 100, up to 4.3 more on the total

Made of editorial 45, provenance 57.

Why it scored 51: The API and MCP live in Pro and Enterprise, which are proprietary with clear licence terms and a perpetual fallback licence. Lite is MIT (15). Privacy policy from INOVECTOR DIGITAL S.R.L. of Moldova names Hetzner, DigitalOcean, PayPal and Sentry, but has no date, no DPA and vague retention (12). v7.0.0 is flagged breaking and the MIXPOST_CORE_PATH default change is documented, with no formal deprecation policy (8). Cloud subprocessors and countries named. We found no statement on whether self-hosted installs report anything back (10).

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: mixpost.app, registered 2022-07-28 (4 years) (7 of 15)
- Endpoint on the vendor's domain:  is not on mixpost.app (0 of 15)
- Status page: not found (0 of 10)
- security.txt: not found (0 of 10)

## 6. Schema & documentation, 76 out of 100, up to 3.9 more on the total

Why it scored 76: OpenAPI 3.1 linked from the API docs (25). No llms.txt found (0). The MCP tools page groups 30 tools and labels each read, write or destructive (12). Inputs typed in the spec (12). A dedicated errors page, consistent JSON error shapes, and 422 with errors.limit for plan limits (12). Public release notes for every Pro version (15).

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. Maintenance & community, 63 out of 100, up to 3.2 more on the total

Why it scored 63: Pro v7.0.3 on 30 September 2026 (30). v7.0.0, v7.0.1, v7.0.2 and v7.0.3 between 26 and 30 September, after v6.3.0 and v6.3.1 in July and August (20). The public Lite tracker shows no maintainer replies on recent issues, and Pro support is private (8). No official SDKs or registry entry (0). Lite has CI but last released 2.6.0 on 13 March 2026 (5).

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.

- 2026-02-24. Issue #194 reports path traversal in the system log download and clear endpoints of Mixpost Lite. On 1 October 2026 the main branch still builds the path as the log directory plus the user-supplied filename (src/Support/SystemLogs.php, getFilePath), so a signed-in user can read or truncate files outside the logs folder. No fix or advisory. We couldn't check whether Pro shares the code. -4 (https://github.com/inovector/mixpost/issues/194)

## 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 Pro and Cloud share the Lite system-log path traversal, and whether the Lite XSS report (#204) is real
- unchecked: Mixpost Cloud prices, which the pricing page didn't show
- Whether self-hosted Pro installs contact Inovector for licence checks or telemetry
- unchecked: Pro's CI and issue tracker, which aren't public

## Weaknesses

- No API or MCP in the free Lite edition
- Tokens carry the full authority of the user who created them, with no scopes
- Public path-traversal (24 February 2026) and XSS (17 June 2026) reports on the Lite repo, still open with no advisory
- No rate limiting of its own, no idempotency keys and no status page for Cloud
- Self-hosting needs your own developer app approved by each network

## 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 list-workspaces first. Workspace endpoints sit under /api/{workspaceUuid}
- Check MIXPOST_CORE_PATH. It's empty by default from Pro v7 but defaults to mixpost in older versions and Lite
- Create the token as a Viewer-role user when the agent only needs to read
- Use unschedule-post rather than delete-post when a person wants a post pulled back to draft
- Expect HTTP 422 with an errors.limit entry when a Cloud plan limit is hit

## What the review panel asked for

- Published Cloud prices
- Advisory for traversal report
- patch the log traversal
- token scopes

## 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.