v3.6.0

Added

• Agent-as-tool composition — Wrap any agent as a RubyLLM tool with AgentTool adapter. Use tools AgentTool.from(OtherAgent) to let agents call other agents. Execution hierarchy tracked via parent_execution_id in metadata
• Queryable agents — Query execution history directly from agent classes: .executions, .last_run, .failures(since:), .total_spent(since:), .stats(since:), .cost_by_model(since:), .with_params(**params). Includes replay support for A/B testing models on real inputs
• ActiveSupport Notifications — Instrument the full pipeline with ruby_llm_agents.* events:
  • Execution lifecycle: execution.start, execution.complete, execution.error
  • Cache: cache.hit, cache.miss, cache.write
  • Budget: budget.check, budget.record, budget.exceeded
  • Reliability: reliability.fallback, reliability.exhausted
• Custom middleware — Inject custom middleware into the pipeline globally via config.middleware or per-agent via middleware DSL. Supports before/after/around positioning relative to built-in middleware
• Agent rename support — Three complementary approaches for handling agent class renames:
  • Aliases DSL — aliases "OldName", "AnotherOldName" on agent classes makes by_agent scopes, analytics, and budget checks automatically include records from all previous names
  • Programmatic helper — RubyLLM::Agents.rename_agent("Old", to: "New") updates execution records and tenant budget keys in-place, with dry_run: true support
  • Migration generator — rails generate ruby_llm_agents:rename_agent OldName NewName creates a reversible migration
  • Rake task — rake ruby_llm_agents:rename_agent FROM=Old TO=New [DRY_RUN=1] as a CLI alternative
• Debugging helpers — Configuration#to_h, BaseAgent.config_summary, Result#execution for console inspection
• Parameter descriptions — desc: / description: keyword on param DSL for documenting agent parameters
• Dashboard enhancements — Custom date range picker for stats/charts, cache savings display, top tenants overview, favicons

Changed

• Tenant middleware now supports objects responding to llm_tenant_id in addition to string/symbol tenant IDs
• Deep symbolize hash keys in agent response processing for consistent access patterns
• Replaced test doubles with real objects across spec suite for more reliable tests

Removed

• Dead code cleanup: removed unused Reliability::Executor sub-classes, duplicate error classes, orphaned async_max_concurrency config, unimplemented redaction stub, hardcoded pricing constants, dead Pipeline convenience methods and Instrumentation diagnostic methods