Migrating from 0.3.x to 0.4.0¶

0.4.0 is the EU AI Act compliance line. It is additive for almost everyone — the compliance kit, MCP integration, typed outputs, session memory, and step-level durability are all new, opt-in surface. There is one breaking change.

Breaking change: the Orchestrator alias is removed¶

Orchestrator was a deprecated compatibility alias for AgentSession (it has emitted a DeprecationWarning since 0.2.1, noting removal "no earlier than 0.4.0"). It is now gone.

# Before (0.3.x) — REMOVED in 0.4.0:
#   from techrevati.runtime import Orchestrator
#   agent = Orchestrator(role="writer", phase="draft")

# After (0.4.0):
from techrevati.runtime import AgentSession

agent = AgentSession(role="writer", phase="draft")

The constructor and behavior are identical — this is a name change only. If you consume the runtime through a re-export shim, update the shim's export list.

New in 0.4.0 (all opt-in, no migration required)¶

• EU AI Act compliance kit — from techrevati.runtime.compliance import EUAIActComplianceKit; wire via AgentSession(compliance=kit) or attach just the audit log via AgentSession(audit_log=...). See EU AI Act.
• MCP tools — pip install 'techrevati-runtime[mcp]'; MCPToolAdapter. See MCP Tools.
• Typed outputs — OutputSpec[T] (JsonOutputSpec, RegexOutputSpec, CallableOutputSpec). See Typed Outputs.
• Session memory — ConversationMemory + compaction. See Session Memory.
• Step-level durability — StepCheckpointSaver.put_step / get_step / list_steps. See Durability.
• PostgreSQL / Redis — [postgres] / [redis] extras + adapter recipes.

Behavioral notes carried from 0.2.x / 0.3.x¶

If you are jumping several versions, these earlier changes still apply:

• GuardrailViolatedError.violations is a tuple of all guardrails that fired at a stage (was first-only before 0.2.1).
• Non-cost overruns raise UsageLimitExceededError, not BudgetExceededError. Catch the common base UsageBoundExceededError for both.
• The OpenTelemetry sink emits nested parent/child spans (since 0.2.0), not one-shot spans — APM filters keyed on gen_ai.operation.name may need broadening.
• 0.3.x constructors validate inputs more strictly (__post_init__); inputs that were silently accepted before (empty role, non-int project_id, negative token counts) now raise.

Not changed in 0.4.0¶

ProviderRouter and RecoveryRecipe.step_retries defaults are unchanged in 0.4.0. (Earlier roadmaps floated reworking them here; doing so without a concrete motivation would be a gratuitous break for downstream consumers, so it is deferred.)