Drift Session Handover Authoring

Use this skill when you are about to call drift_session_end and must produce the handover artifacts required by ADR-079 and the session-handover contract in .github/prompts/_partials/session-handover-contract.md.

When To Use

• You touched files under src/drift/ during the session.
• You completed one or more fix-plan tasks.
• You ran multiple scans / diffs / nudges and want to hand off to the next agent (or to the maintainer).
• drift_session_end returned DRIFT-6100 and you need to fill the missing artifacts.

When Not To Use

• Empty sessions (no tool calls beyond session start, no completed tasks, no touched files). The gate auto-exempts them.
• Pure read-only exploration that touched no code.

Core Rules

1. Agent writes, server validates. You author the artifacts. The MCP server only checks existence, shape, placeholders (and optionally runs an LLM review). Do not try to satisfy the gate with generated filler.
2. No placeholder tokens. TODO, FIXME, XXX, TBD, ???, <N>, <NNN>, LOREM, IPSUM, FOO, BAR, BAZ outside of ≥5-line code fences block the gate at L3.
3. Cross-check session id. The session_id in the Markdown frontmatter must match the active session exactly.
4. SIGNAL / ARCHITECTURE classes require all three artifacts. Evidence JSON, ADR draft, and session markdown.
5. force=true is a last resort. It requires an auditable bypass_reason of at least 40 characters without placeholder tokens, and it is logged and persisted in the session trace.

Step 1: Policy Gate

Before writing artifacts, run the mandatory gate from .github/instructions/drift-policy.instructions.md. If the underlying change is inadmissible the gate blocks you here, not at drift_session_end.

Step 2: Determine Your Change Class

Ask yourself what the session actually changed:

When in doubt, pick the highest-priority class that applies.

Step 3: Author the Session Markdown

Copy docs/session_handover_template.md into work_artifacts/session_<first 8 chars of session_id>.md and fill every required section. Minimum length ≥ 200 bytes (the template already exceeds this when filled meaningfully).

Required frontmatter fields:

• session_id (full id, matching the active session)
• duration_seconds
• tool_calls
• tasks_completed
• findings_delta
• change_class

Required sections:

1. ## Scope — what you changed and what you deliberately did not.
2. ## Ergebnisse — observable outcomes (tests, metrics, behaviour).
3. ## Offene Enden — known follow-ups. Write "Keine offenen Enden" (no "TODO") if there really are none.
4. ## Next-Agent-Einstieg — the exact first tool call and the first file path the next agent should open.
5. ## Evidenz — pointers to the evidence JSON, ADR, and updated audit artifacts.

Step 4: Author the Evidence JSON (signal / architecture only)

Use the drift-evidence-artifact-authoring skill to produce a versioned file in benchmark_results/. The gate's L2 layer requires these JSON keys at minimum:

• version
• feature
• description
• tests
• audit_artifacts_updated (non-empty list when the class is signal or architecture)

Step 5: Author the ADR Draft (signal / architecture only)

Use the drift-adr-workflow skill. The gate's L2 layer requires:

• Frontmatter status: proposed or accepted.
• ## Kontext with ≥ 120 substantive characters.
• At least two explicit "Alternative" mentions.
• ## Entscheidung and ## Konsequenzen sections with non-empty content.

Step 6: Call drift_session_end

Pass explicit paths so the server can skip path-discovery:

drift_session_end(
    session_id="<sid>",
    session_md_path="work_artifacts/session_<id8>.md",
    evidence_path="benchmark_results/v<ver>_<slug>_feature_evidence.json",
    adr_path="docs/decisions/ADR-<NNN>-<slug>.md",
)

If the gate blocks, read the missing_artifacts, shape_errors, and placeholder_flags arrays in the response and fix the specific issue before retrying.

Step 7: Force-Bypass (Notausgang)

Only if a release-critical hotfix makes full artifacts impossible and a follow-up task is already queued:

drift_session_end(
    session_id="<sid>",
    force=True,
    bypass_reason=(
        "Hotfix-Session fuer Release-Blocker; Evidence-JSON und ADR "
        "werden im Follow-up-Task <task-id> bis <date> nachgereicht."
    ),
)

The reason must be specific, meaningful, and free of placeholder tokens. force=true is logged at WARNING level and recorded in the session trace. After the limit of 5 blocked retries the gate auto-unblocks if — and only if — a valid bypass_reason is supplied.

Validation

• drift_session_end returns status: ok with handover_gate.ok=true, or handover_bypass.forced=true with a valid reason.
• The session markdown shows up in git status under work_artifacts/.
• Evidence JSON and ADR are parseable and referenced from the session markdown's ## Evidenz section.

References

• docs/decisions/ADR-079-session-handover-artifact-gate.md
• .github/prompts/_partials/session-handover-contract.md
• docs/session_handover_template.md
• src/drift/session_handover.py