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MCP and Automation

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github-actions edited this page Jul 2, 2026 · 1 revision

MCP and Automation

The add-in exposes a public API (VCS / clsVersionControl) for scripting, CI, and MCP (Model Context Protocol) agents. Automation can export/import objects, run tests, and execute controlled VBA — but every sensitive capability is disabled by default.

This page is for database owners and administrators deciding what to enable. API details for developers and agents are in the repository AGENTS.md.

What MCP can do (when permitted)

Capability Option gate Risk if misused
Import objects from source files Allow Object Import from Source (McpAllowImport) Overwrites database objects from untrusted source
Call existing public VBA procedures Part of import/VBA policy Runs code already in the database
Read-only SELECT via DAO Allow Read-Only SQL Queries (McpAllowExecuteSQL) Reads data exposed to the add-in connection
Arbitrary VBA in a temp module Allow Arbitrary VBA Execution (McpAllowRunVBA) Highest risk — full VBA execution as the interactive user
Run test suites / round-trip harness Requires Allow Arbitrary VBA Execution Can modify sandbox objects and fixture folders

Configure gates under Options → MCP.

Default posture: all Off

New projects and upgrades leave MCP permissions Off. Agents connecting through an MCP server cannot import, run SQL, or execute arbitrary VBA until an administrator explicitly enables the needed flags in Options and saves vcs-options.json.

Treat enabling Allow Arbitrary VBA Execution like granting macro/VBA trust to an automated operator.

Threat model (practical)

  1. Trust the add-in file — Only install Version Control.accda from official releases or builds you compiled from source.
  2. Trust source files — Import/build runs VBA hooks and object definitions from your .src tree. Protect the repository branch permissions.
  3. Session scope — MCP can use session-scoped option overrides; they should not persist beyond the session without your intent.
  4. UI skipped — Agent operations may auto-resolve merge conflicts and skip dialogs. Human review happens in Git, not in Access prompts.
  5. Index — Single-object agent export/import may skip updating vcs-index.idx by design; run a normal export afterward for consistent Fast Save.

When to enable each permission

Permission Enable when…
Object Import You use an agent to apply reviewed PRs to a dev database; source repo is trusted.
Read-Only SQL Agent needs to inspect data for debugging; no write access required.
Arbitrary VBA You run VCS.RunTests, VCS.RunRoundtripTests, or custom automation via RunVBA; dev machine only.
VBA function calls Agent should call existing project APIs without injecting new code.

For production databases, prefer no MCP permissions or a dedicated sandbox copy.

Related security topics

Further reading

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