DynamicSkillMiddleware

Dynamically composes skills from an ordered list of repositories (AgentSkillRepository) on every call() via #onSystemPrompt(Agent, RuntimeContext, String), replacing the static skill prompt with a per-call view that supports per-user skill isolation and one-click marketplace integration.

The repository list is iterated low-priority first; when two repositories provide a skill with the same AgentSkill#getName(), the later (higher-priority) entry wins.

Rebuilding on every call is intentional: per-user namespaced repositories may return different content under the same skill name as the RuntimeContext switches users, so caching by skill id alone would mask those swaps. A content-addressed cache keyed by the visible-view signature reuses an already-materialised (immutable) box when the visible content is unchanged, so uploadSkillFiles only re-runs when content actually changes. No tools are (re)registered on the shared toolkit.

Subclasses can plug runtime visibility logic (canary lists, environment gates, etc.) by overriding #filterVisible(List, RuntimeContext) — the default implementation returns the input list unchanged.