Fix/preference distillation original date

[mbt1909432]

Why We Need This PR?

Problem

When users upload historical chat messages with original_date set in session configs, the skill learner correctly uses the historical date for task distillation, but user preferences distillation was missing the original_date.

This caused preference MQ messages to have original_date: null, leading to skill files being written with today's date instead of the historical session date.

Production logs showed:

{"original_date": null, "task_id": "00000000-0000-0000-0000-000000000000", ...}

• task_id: "00000000-..." indicates user preferences distillation (not a real task).
• original_date: null was the bug.

Root Cause

task_agent_curd in task.py has two code paths for publishing SkillLearnDistilled:

1. Task Success/Fail distillation – had original_date ✓
2. User Preferences distillation – was missing original_date ✗

Solution

Fetch session.configs.original_date at the start of task_agent_curd and pass it when publishing preferences.

Code Change

File: src/server/core/acontext_core/llm/agent/task.py

async with DB_CLIENT.get_session_context() as db_session:
    # Get session configs to extract original_date
    r_sess = await SD.fetch_session(db_session, session_id)
    session, _ = r_sess.unpack()
    original_date = (
        session.configs.get("original_date")
        if session and session.configs
        else None
    )

    # ... existing task fetch logic ...

# ... later when publishing preferences:
await publish_mq(
    EX.learning_skill,
    RK.learning_skill_agent,
    SkillLearnDistilled(
        ...
        original_date=original_date,  # Added this line
    ).model_dump_json(),
)

Implementation Tasks

• Add original_date fetching from session.configs in task_agent_curd
• Merge session fetch into existing DB_CLIENT.get_session_context() block (avoid breaking atomicity tests)
• Pass original_date when publishing SkillLearnDistilled for user preferences

Files Changed

File	Change
src/server/core/acontext_core/llm/agent/task.py	Add original_date fetch and pass to preferences MQ

Impact Areas

Which part of Acontext would this feature affect?

• Client SDK (Python)
• Client SDK (TypeScript)
• Core Service
• API Server
• Dashboard
• CLI Tool
• Documentation
• Other: ...

[GenerQAQ]

CI Failure Analysis + Suggestion

The 3 failing tests in test_task_agent_atomicity.py all report RuntimeError: coroutine raised StopIteration.

Root cause: These tests mock DB_CLIENT.get_session_context() with a side_effect list to return different mock sessions in order. The PR adds a new, separate get_session_context() block for SD.fetch_session, which consumes an extra entry from the list and exhausts it before the test expects.

Suggestion: Merge SD.fetch_session into the existing DB session block (current L132-143) instead of opening a new one. All three functions (fetch_session, fetch_current_tasks, fetch_planning_task) take the same AsyncSession parameter and are read-only queries — safe to share a single session context. This is consistent with how skill_learner.py (L40-54) already does it.

Roughly:

original_date = None
async with DB_CLIENT.get_session_context() as db_session:
    r_sess = await SD.fetch_session(db_session, session_id)
    sess, _ = r_sess.unpack()
    if sess and sess.configs:
        original_date = sess.configs.get("original_date")

    r = await TD.fetch_current_tasks(db_session, session_id)
    tasks, eil = r.unpack()
    if eil:
        return r
    r_plan = await TD.fetch_planning_task(db_session, session_id)
    planning_task, _ = r_plan.unpack()
    ...

This avoids an extra connection pool checkout and preserves the existing tests' expectations on get_session_context call count.

[GenerQAQ]

LGTM! Clean fix — correctly wires original_date into the preferences distillation path.

One minor suggestion: consider mirroring the eil-guarded pattern from skill_learner.py (L51-58) for consistency and observability:

session, eil = r_sess.unpack()
original_date = None
if not eil and session and session.configs:
    original_date = session.configs.get("original_date")
    LOG.info("task_agent.original_date_parsed", session_id=str(session_id), original_date=original_date)

Not a blocker — the current code is functionally correct.