[FEATURE]:Plan mode should block MCP write tools, not just local file operations

[vaibhavlaturkar]

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Problem

Plan mode currently restricts local file system operations (file edits, bash
commands) but does NOT restrict MCP tool calls. This means an agent in plan
mode can still write to external services like Jira, Confluence, GitHub, etc.

This gives users a false sense of safety — "I'm in plan mode so nothing will
change" — but external API writes go through unblocked.

Expected behaviour

In plan mode, all MCP tools that perform write operations (create, update,
delete) should be blocked, the same way file edits are blocked. Read-only
MCP tools (search, get, list) should still be allowed.

Actual behaviour

MCP write tools execute freely in plan mode. A Jira ticket was updated during
a plan-mode session without any warning or block.

Suggested fix

• Detect write-capable MCP tools (or tools not marked read-only) and block
  them in plan mode
• Optionally show a warning: "This tool would make external changes —
  blocked in plan mode"

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• MCP filesystem tools bypass plan mode edit: deny permission rule #30291: MCP filesystem tools bypass plan mode edit: deny permission rule — covers the same core problem of MCP tools not being blocked in plan mode, though it focuses on filesystem MCP tools rather than external-service write tools (Jira, Confluence, GitHub, etc.)

If your request goes beyond #30291 (i.e., extending blocking to all MCP write operations against external services, not just filesystem tools), please clarify the distinction so this can be tracked separately.

[rekram1-node]

Detect write-capable MCP tools (or tools not marked read-only) and block
them in plan mode

There isnt really a way to detect this afaik, best that u just set permissions as needed for ur mcps that u use instead