Permission rules use first-match-wins instead of documented last-matching-rule-wins #31854

Description

The Permissions documentation states:

Rules are evaluated by pattern match, with the last matching rule winning. A common pattern is to put the catch-all "*" rule first, and more specific rules after it.

However, the actual implementation uses first-matching-rule-wins. This means the documented "common pattern" of putting "*": "deny" first with specific "allow" overrides after it never works — the catch-all always takes priority.

Example

{
  "edit": {
    "*": "deny",
    "Docs/*": "allow"
  }
}

• Expected per docs: editing Docs/foo.md is allowed (last match Docs/* → allow)
• Actual: editing Docs/foo.md is denied (first match * → deny)

Workaround

List allow rules before deny rules, and avoid using a catch-all "*" entirely:

{
  "edit": {
    "Docs/*": "allow",
    "*.cs": "deny"
  }
}

This happens to work because the first match (allow) wins, but it contradicts the documented behavior.

Plugins

Jetbrains - OpenCode UI

OpenCode version

1.17.3

Steps to reproduce

1. Create opencode.json with:

{
  "agent": {
    "Design": {
      "permission": {
        "edit": {
          "*": "deny",
          "Docs/*": "allow"
        }
      }
    }
  }
}

2. Start opencode with opencode --agent test
3. Ask the agent to edit a file under Docs/ (e.g. Docs/readme.md)
4. Observe that the edit is denied even though the specific Docs/*: allow rule should take precedence per documentation

Screenshot and/or share link

Operating System

Windows 10 Pro 24H2 (build 26100)

Terminal

Windows Terminal, PowerShell 5.1