fix: use case-insensitive matching for prometheus agent detection

[code-yeongyu]

Summary

• Fix prometheus-md-only hook's agent name detection which used exact string equality (agentName !== "prometheus") and failed when display names like "Prometheus (Plan Builder)" were stored in session state
• Replace with case-insensitive substring matching via isPrometheusAgent() helper, consistent with the pattern used in keyword-detector hook

Problem

The prometheus-md-only hook enforces that Prometheus can only write .md files inside .sisyphus/. However, the agent detection logic used exact match:

// Before (fragile)
if (agentName !== PROMETHEUS_AGENT) return

getSessionAgent() can return display names (e.g., "Prometheus (Plan Builder)", "Prometheus (Planner)") depending on how OpenCode stores the agent name. When this happens, the hook silently fails to activate, allowing Prometheus to write arbitrary files — bypassing the policy enforcement.

Solution

Extract a robust matcher into agent-matcher.ts:

export function isPrometheusAgent(agentName: string | undefined): boolean {
  return agentName?.toLowerCase().includes(PROMETHEUS_AGENT) ?? false
}

This matches the pattern already used by keyword-detector/ultrawork/source-detector.ts.

Testing

Added 6 new test cases covering:

• Exact name "prometheus" → blocked ✅
• Display name "Prometheus (Plan Builder)" → blocked ✅
• Display name "Prometheus (Planner)" → blocked ✅
• Uppercase "PROMETHEUS" → blocked ✅
• Non-Prometheus agent "sisyphus" → not blocked ✅
• Undefined agent → not blocked ✅

All 35 tests pass. Typecheck clean.

Related

Closes #1764 (Bug 3: Prometheus Detection)

---

Summary by cubic

Make Prometheus md-only enforcement reliable by detecting the agent with case-insensitive substring matching. Also clarify errors for namespaced marketplace slash commands.

• Bug Fixes
  • Prometheus md-only: replace exact match with isPrometheusAgent (case-insensitive substring) to catch display names like “Prometheus (Plan Builder)” and uppercase variants; aligns with keyword-detector. Added 6 tests. Closes [Meta-Issue]: Critical Orchestration Regressions in v3.5.x - Skills, Todos, and Agent Detection #1764.
  • Slash commands: detect namespaced commands (contain “:”) and show a clear “marketplace plugins not supported” message with guidance to use .claude/commands, in both executor and tool. Closes Claude plugin command compatibility: /daplug:run-prompt not resolved in OpenCode #1682.

^{Written for commit c12c6fa. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 5 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Auto-approved: Changes are low-risk: 1) Error message improvements for marketplace plugin commands (better UX, no logic change), 2) Refactored agent matching from exact string to case-insensitive includes (safer, no}