Session Lifecycle Patterns

Structure AI agent sessions for predictable outcomes, context preservation, and clean handoffs.

The Phase Model

FRAME → SHAPE → BUILD → PROVE → DONE
  ↑       ↑       ↑       ↑
  └───────┴───────┴───────┘
     (back-transitions allowed)

Phase Definitions

Phase	Purpose	Activities	Gate
FRAME	Understand context	Explore code, read docs, ask questions	Can articulate the problem
SHAPE	Design approach	Create plan, identify files, consider tradeoffs	Plan reviewed and approved
BUILD	Implement	Write code, create files, apply changes	Implementation complete
PROVE	Verify	Run tests, validate output, check quality	All checks pass
DONE	Close	Summarize, commit, document decisions	Session artifacts preserved

Phase Transitions

VALID_TRANSITIONS = {
    "FRAME": ["SHAPE"],
    "SHAPE": ["FRAME", "BUILD"],       # Can go back to reframe
    "BUILD": ["SHAPE", "PROVE"],       # Can go back to reshape
    "PROVE": ["BUILD", "DONE"],        # Can go back to fix
    "DONE": [],                        # Terminal
}

def can_transition(current: str, target: str) -> bool:
    return target in VALID_TRANSITIONS.get(current, [])

Phase Anti-Patterns

• Skipping FRAME — Jumping to code without understanding the problem
• SHAPE → BUILD without approval — Building before alignment on approach
• Staying in BUILD forever — Not proving that the work is correct
• PROVE → DONE without evidence — Claiming completion without verification

Session Metadata

Session Record Structure

session:
  id: "sess_2026-03-20_a1b2c3"
  started: "2026-03-20T10:58:00Z"
  ended: "2026-03-20T12:30:00Z"
  phase_history:
    - phase: FRAME
      entered: "2026-03-20T10:58:00Z"
      duration_minutes: 15
    - phase: SHAPE
      entered: "2026-03-20T11:13:00Z"
      duration_minutes: 20
    - phase: BUILD
      entered: "2026-03-20T11:33:00Z"
      duration_minutes: 45
    - phase: PROVE
      entered: "2026-03-20T12:18:00Z"
      duration_minutes: 12
  scope:
    organ: IV
    repo: a-i--skills
    task: "Create python-packaging-patterns skill"
  artifacts:
    files_created: [skills/development/python-packaging-patterns/SKILL.md]
    files_modified: []
    commits: ["abc123"]
  decisions:
    - "Chose hatchling as recommended build backend"
    - "Included namespace package pattern for multi-repo use"

Context Preservation

Intra-Session Context

Maintain context as the session progresses through phases:

class SessionContext:
    def __init__(self):
        self.discoveries: list[str] = []   # FRAME findings
        self.plan: dict = {}               # SHAPE output
        self.changes: list[str] = []       # BUILD artifacts
        self.evidence: list[str] = []      # PROVE results

    def frame_discovery(self, finding: str):
        self.discoveries.append(finding)

    def shape_decision(self, key: str, value: str, rationale: str):
        self.plan[key] = {"value": value, "rationale": rationale}

Inter-Session Context

For multi-session work, preserve essential context at session end:

## Session Close Summary

### What was accomplished
- Created 6 Wave 0 skills (python-packaging-patterns through vector-search-patterns)

### What remains
- 18 more Wave 0 skills in Batches 2-4
- Waves 1-4 pending

### Key decisions
- Using governance_norm_group: repo-hygiene for packaging/config skills
- Using organ_affinity: [all] for cross-cutting infrastructure skills

### Blockers
- None

### Next session should start by
- Reading this summary
- Continuing with Wave 0 Batch 2

Session Types

Exploration Session

FRAME (80%) → SHAPE (20%) → DONE

Heavy on reading, light on planning, no implementation. Produces understanding and a plan for a future BUILD session.

Implementation Session

FRAME (10%) → SHAPE (15%) → BUILD (55%) → PROVE (20%) → DONE

Quick reorientation, then focused building and verification.

Debug Session

FRAME (40%) → BUILD (30%) → PROVE (30%) → DONE

Heavy investigation, targeted fix, thorough verification.

Review Session

FRAME (30%) → PROVE (70%) → DONE

Mostly reading and validating existing work.

Multi-Session Continuity

Session Chains

When work spans multiple sessions, each session references the chain:

chain:
  id: "skill-fortification-campaign"
  session_index: 3
  total_sessions_estimated: 15
  previous_session: "sess_2026-03-20_wave0-batch1"
  completed_items: ["A1", "A2", "A3", "A4", "A5", "A6"]
  remaining_items: ["A7", "A8", "A13", "A14", "B1", "B2", ...]

Handoff Protocol

At session end, produce a handoff document:

1. State snapshot — What exists now (files, branches, test status)
2. Decision log — Why choices were made (so next session doesn't re-litigate)
3. Next actions — Exactly what to do next, with no ambiguity
4. Risk flags — Anything the next session should watch for

Session Quality Signals

Signal	Healthy	Unhealthy
Phase transitions	Sequential with occasional back-steps	Skipping phases, staying in one phase
FRAME duration	10-30% of session	<5% or >50%
PROVE evidence	Concrete test/validation output	"I think this works"
Context preserved	Summary written at DONE	Session ends abruptly
Scope creep	Stays within stated scope	Expanding mid-BUILD

Anti-Patterns

• Infinite FRAME — Analysis paralysis; at some point, start shaping
• Skipping PROVE — Every BUILD must be proved before DONE
• No session close — Always write a summary, even if brief
• Context loss between sessions — Handoff documents are mandatory for multi-session work
• Phase theater — Going through motions without substance in each phase