ClickSend SMS API + MCP vs Linq

ClickSend SMS API + MCP 37

No public OpenAPI spec found. The MCP package bundles an OpenAPI 3.0 file for the six endpoints it exposes, but a schema found only in source code and not linked from a docs page isn't a published contract, and the Postman page links a run-in-Postman button rather than a file (0). llms.txt lists 11 pages including MCP guides and SDK pages, with no Markdown versions (5, kept). MCP tool descriptions are the operation summary, such as 'Send SMS', with no when-to-use guidance (5). Typed inputs generated from the spec (10). Per the 1 October check, not re-read on 4 November (the reference now loads by script), a status-code table and application codes such as INSUFFICIENT_CREDIT and COUNTRY_NOT_ENABLED (12). /v3 path, SDK migration guides and no public API changelog (5). 0+5+5+10+12+5 = 37.

Linq 93

OpenAPI 3.1 file for the Partner API and another for WhatsApp, both public (25). llms.txt, llms-full.txt and Markdown for every page (10). Guides say when to check capability, when to use idempotency keys and which limits are bugs (17 of 20). 93 enums in the spec and typed parts for messages (14 of 15). Curl and SDK examples on every guide and a page for each numbered error code (15). Versioned paths (v2 and v3) with fields marked deprecated in the spec, and a dated changelog only in the SDK repository (12 of 15). 25 + 10 + 17 + 14 + 15 + 12 = 93.

ClickSend SMS API + MCP 62

clicksend-client 6.0.2 tagged on 25 September 2026 (20, within 90 days, cause time). In the 90 days from 6 August, the Node SDK clicksend v6.0.0 (2 September), v6.0.1 (8 September) and v7.0.0 (11 September) from ClickSend/clicksend-nodejs-v2, Python 6.0.2, and the MCP package 2026.8.23 (20). The 1 October check counted two, missing the v2 SDK repositories. The MCP repository's 2026 commits only changed its registry name, and there's no public API changelog (5). Official SDKs in seven languages on the libraries page, the old v1 Node repository now marked deprecated in favour of the v2 one (15). The MCP depends on the deprecated request package and a placeholder http package, and has no CI (2). 20+20+5+15+2 = 62.

Linq 83

@linqapp/sdk and @linqapp/sdk-mcp 0.80.0 on 5 November 2026 (30). Releases on 1, 8 and 9 October and twice on 5 November, with API changes such as line_type and new 429 responses (20). Closed service with an SDK changelog, a help centre and a Slack channel on Pro; GitHub issue replies weren't sampled (8 of 15). io.github.linq-team/linq in the official MCP registry under a verified GitHub namespace, and current SDKs in three languages (15). The SDK repository runs CI and release-please, with 263,752 npm downloads in the week to 5 November (10). 30 + 20 + 8 + 15 + 10 = 83.

ClickSend SMS API + MCP 70

6 MCP tools, with inputs generated from the spec (20 of 25). Pages with page and limit (15 to 100) and a next_page_url, and SMS history filters by date, which the MCP parses from natural language (20). HTTP and application error codes, though the MCP returns them as plain text (15 of 20). No idempotency key on sends and no tool annotations (0 of 20). SDKs in ten languages, and a send needs only a recipient and a body (15).

Linq 90

The MCP server has two tools, code execution against the SDK and docs search, so its definitions cost little context (25). Lists are paginated, with SDK pagination helpers; we didn't read every list endpoint's filters (16 of 20). Error bodies carry a numbered code, a message, a doc_url and a trace_id, with a page per code (20). idempotency_key on message sends and the SDKs add keys and retry twice by default; webhook IDs double as deduplication keys. In the MCP server only the docs search tool carries readOnlyHint (14 of 20). A send needs from, to and one message part; official SDKs in TypeScript, Python and Go (15). 25 + 16 + 20 + 14 + 15 = 90.

ClickSend SMS API + MCP 30

HTTP Basic auth with the account username and one API key, and subaccounts get their own keys. The MCP server still writes the full request options, the Basic Authorization header included, to stderr on every call (repository unchanged since 11 August 2026), and MCP hosts keep stderr in log files (10 of 30). No read-only mode or confirmation before sends. Subaccounts give some separation (5 of 20). Inbound replies and SMS history are untrusted text returned straight to the model, with no injection guidance (0 of 15). SMS history and statistics by API (8 of 15). The security page now loads and names only AWS's certifications. ClickSend's footer links Sinch's trust centre for ClickSend, which gives security@sinch.com to report a vulnerability and posts dated vulnerability notes. Its ISO 27001 and SOC 2 badges "may apply to specific products" and aren't stated for ClickSend, and no security.txt (404) or bug bounty was found, so a reporting route with no acknowledgement time (7). 10+5+0+8+7 = 30.

Linq 50

Bearer API keys in a header, never in the query string, rotated or revoked in the dashboard, scoped to the account with no per-action or read-only scopes (20 of 30). Sandbox keys reach only verified handles, and the MCP server's --code-allow-http-gets and method allow and block lists limit its code tool; no approval step for sends (10 of 20). Inbound iMessage and SMS text reaches the agent, and no prompt-injection guidance was found in the docs or the MCP instructions (0 of 15). Every response carries a trace_id; no operator request log was found in the docs (5 of 15). SOC 2 Type II reports for 2024, 2025 and 2026 and a 2026 penetration test on request, a vulnerability disclosure policy open on the trust centre and SECURITY.md in the SDK repository; no security.txt or bug bounty (15 of 20). 20 + 10 + 0 + 5 + 15 = 50.

ClickSend SMS API + MCP 20

No x402, MPP or L402 (0). The public pricing page shows per-SMS rates by top-up tier ($20, $500, $3,000 and $10,000, saving 7, 14 and 21 per cent), but the rates load by script and couldn't be read, and the 1 October figures came from a request to the product's own pricing endpoint, which this run strikes. So the readable pricing is tier-only (10). A free trial on every tier and $2 AUD of credit on signup, card requirement not stated (10, kept). A person signs up in a browser (0). 0+10+10+0 = 20.

Linq 40

No x402, MPP or L402 (0). Public plan prices only, Hobby $0 and Pro from $260 a month, with no per-message fee (10 of 20). Hobby is free with no card, and the Pro trial needs no card (20). linq signup creates an account, an API key and a number from a terminal, but a person has to read back the emailed code, so half (10 of 20). 0 + 10 + 20 + 10 = 40.

ClickSend SMS API + MCP 65

Statuspage at status.clicksend.com with component history, read through its history.atom feed on 4 November (20). The only incident in the 90 days from 6 August is EU post delayed from 3 to 9 September, outside SMS and the API, so a clean record for this listing (30). No rate limit numbers published (0). Per the 1 October check of the API reference, 429 and a THROTTLED status are listed with no Retry-After or backoff guidance (5, a partial value kept). The reference now renders only by script and wasn't re-read on 4 November. No SLA found (0). REST API v3 is generally available (10). 20+30+0+5+0+10 = 65.

Linq 83

Read with the hosted lines. status.linqapp.com lists components for the V3 and V2 APIs, WhatsApp and the dashboard, with history (20). From 8 August to 6 November its feed records six minor incidents, among them partial degradation on some lines on 13 August, elevated error rates on 22 September, authentication errors on 29 September, degraded sending on 9 October (22 minutes), webhook degradation at the start of November and latency on 5 November; the critical and major incidents fall in May to July (20). Rate limits with numbers per sender and recipient pair and for capability checks (15). 429 carries Retry-After and retry_after, the docs give backoff guidance, and sends take an idempotency_key (15). llms.txt states 99.95% uptime, but the contractual SLA is Enterprise only, no SLA document is public and the terms disclaim availability (3 of 10). Partner API v3 is generally available (10). 20 + 20 + 15 + 15 + 3 + 10 = 83.