Add AccountsOS third-party MCP plugin

[paulgosnell]

Adds AccountsOS (https://accounts-os.com), an AI-native accounting platform for UK limited companies and sole traders, as a third-party plugin.

What it is

• Hosted MCP endpoint (https://accounts-os.com/api/mcp, type: http) with Bearer auth via a typed ACCOUNTSOS_API_KEY variable. Nothing runs locally, no npm download.
• 4 auto-firing skills with UK tax knowledge (corporation tax, VAT/MTD, expense deductibility, filing deadlines), figures verified for the 2026/27 tax year against gov.uk.
• 6 slash commands (/weekly-check, /vat-check, /deadlines, /invoices, /log-expense, /categorize).

Security declaration

• The only network endpoint the plugin calls is https://accounts-os.com/api/mcp.
• The only credential is ACCOUNTSOS_API_KEY, user-created and revocable in AccountsOS settings, scoped to the user's own company data.
• No hooks, no shell execution, no postinstall scripts. Skills and commands are plain markdown.

Checks

• scripts/validate-plugins.mjs passes locally (manifest + marketplace entry).
• Plugin source is maintained at https://github.com/thriveventurelabs/accountsos-agent-plugin (MIT), same repo that serves the Claude and Grok Build plugin ecosystems.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Aix7YPfN9j2268KUHUZo1Q

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Note

Medium Risk
Users supply a third-party API key to a remote service with read/write accounting access; risk is bounded to markdown plus one external endpoint (no hooks or local execution), but mistaken agent actions could change real financial records.

Overview
Adds AccountsOS as a new third-party integration under third_party/accountsos/, and registers it in .cursor-plugin/marketplace.json and the root README plugin table (author: Thrive Venture Labs).

The plugin wires Cursor to a hosted HTTP MCP at https://accounts-os.com/api/mcp via mcp.json, with a required ACCOUNTSOS_API_KEY variable in plugin.json so the client can prompt for configuration. Beyond MCP, it ships four auto-trigger UK tax skills (2026/27) and six slash commands (weekly-check, log-expense, vat-check, deadlines, invoices, categorize) as markdown-only workflows that call AccountsOS tools. Supporting docs include README, CHANGELOG (v1.3.0), and MIT license with a tax-disclaimer addendum.

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