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praxis/server/scenarios/runtime.py
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Praxis CI fbd6602814 docs(milestone): complete v0.1 foundation
---ci---
phase: 0
milestone: v0.1
status: complete
---/ci---
2026-08-01 13:32:48 +00:00

103 lines
3.5 KiB
Python

"""Scenario runtime — maps a Scenario to a Pipecat Flows state machine (TASK-03-03).
The v0.1 branch point is a post-hoc outcome classification (G-002): the
conversation is linear, and at session end an LLM-as-judge (TASK-03-06)
classifies the learner's signals into accept_resolution or escalate. Pipecat
Flows is wired so the branch field is part of the data model; Phase 2+ can
activate true in-flight branching without a schema change.
This module:
- builds the system prompt from scenario.setup.system_prompt
- provides the opening line (scenario.setup.opening_line) as the first TTS utterance
- exposes the branch transition logic (driven by the classifier in TASK-03-06)
TASK-03-07: the pipeline uses scenario-driven prompts instead of the
SLICE-02 hardcoded walking-skeleton prompt.
"""
from __future__ import annotations
from dataclasses import dataclass
from typing import Any
from server.scenarios.schema import Branch, Scenario
@dataclass
class ScenarioRuntime:
"""Runtime state for one scenario session."""
scenario: Scenario
branch: Branch | None = None
turn_count: int = 0
@property
def system_prompt(self) -> str:
return self.scenario.setup.system_prompt
@property
def opening_line(self) -> str:
return self.scenario.setup.opening_line
@property
def branch_id(self) -> str | None:
return self.branch.id if self.branch else None
@property
def outcome(self) -> str | None:
return self.branch.outcome if self.branch else None
def set_branch(self, branch_id: str) -> Branch:
"""Set the session's branch outcome (from the classifier, TASK-03-06)."""
b = self.scenario.branch_by_id(branch_id)
if b is None:
raise ValueError(
f"Unknown branch id {branch_id!r} for scenario {self.scenario.id!r}; "
f"known: {self.scenario.branch_ids()}"
)
self.branch = b
return b
def debrief_focus(self) -> str:
"""The debrief focus for the resolved branch (or a default)."""
if self.branch:
return self.branch.debrief_focus
return "General coaching feedback for this session."
def as_flow_spec(self) -> dict[str, Any]:
"""Render the scenario as a Pipecat Flows state-machine spec.
v0.1: a single 'conversation' state with the system prompt; branch
transitions are post-hoc (G-002). The spec carries the branch metadata
so Phase 2+ can fork in-flight.
"""
return {
"initial_state": "conversation",
"states": {
"conversation": {
"system_prompt": self.system_prompt,
"opening_line": self.opening_line,
"branches": [
{"id": b.id, "outcome": b.outcome,
"learner_signals": b.trigger.learner_signals}
for b in self.scenario.branches
],
},
},
"transitions": [], # v0.1: no in-flight transitions (G-002)
}
def build_runtime(scenario: Scenario) -> ScenarioRuntime:
"""Construct a ScenarioRuntime for the given scenario."""
return ScenarioRuntime(scenario=scenario)
def build_runtime_from_id(scenario_id: str) -> ScenarioRuntime:
"""Load + build a runtime by scenario id (convenience for the pipeline)."""
from server.scenarios.loader import load
return build_runtime(load(scenario_id))
__all__ = ["ScenarioRuntime", "build_runtime", "build_runtime_from_id"]