Dev Session

Manage multi-session development work with structured progress files, checkpoint commits, and durable learnings. Produces SESSION.md files that survive context compaction and enable clean handoff between sessions.

Operating Modes

Mode 1: Start Session

When: Beginning multi-step work, "start session", "new session for [feature]"

• Check if SESSION.md already exists in the project root

• If yes: read it and ask whether to continue the existing session or start fresh

• If no: create from template (see references/session-template.md)

• Pre-fill fields:

• Project: from CLAUDE.md or directory name

• Branch: from git branch --show-current

• Last Updated: current timestamp

• Phase: ask user what they're working on

• Read the project's CLAUDE.md to orient on context

• Present a brief summary: "Session started. Working on [phase] on branch [branch]."

Mode 2: Checkpoint

When: "checkpoint", major milestone reached, before risky changes, context getting large

• Update SESSION.md:

• Add completed items to What Works

• Update Current Position with exact location (file paths, line numbers)

• Clear resolved Blockers, add new ones

• Write concrete Resume Instructions

• Capture learnings:

• If any patterns, gotchas, or commands were discovered during work, add them to CLAUDE.md

• One line per concept — concise, not verbose

• Git checkpoint: git add -A && git commit -m "WIP: [what was accomplished]"

• Record the commit hash in SESSION.md under Checkpoint

• Confirm: "Checkpointed at [hash]. SESSION.md updated."

Mode 3: Resume Session

When: "resume", "continue from last session", "where were we", start of a new conversation

• Read SESSION.md — if missing, inform user and offer to start a new session

• Read the project's CLAUDE.md for context

• Check what's changed since the recorded checkpoint: git log --oneline [checkpoint-hash]..HEAD

• Check for uncommitted changes: git status

• Present a summary:

• Phase: what we were working on

• Position: where we left off

• Changes since: any commits or modifications since checkpoint

• Blockers: anything unresolved

• Suggested next step: first item from Resume Instructions

Mode 4: Wrap Session

When: "wrap session", "done for now", "save progress", ending a session

• Run a full checkpoint (Mode 2)

• Review SESSION.md for completeness:

• Are Resume Instructions concrete enough for a fresh session to continue?

• Is Current Position specific (file paths, not vague descriptions)?

• If the phase is complete:

• Collapse the phase summary to 2-3 lines

• Clear Resume Instructions or note "Phase complete — ready for next phase"

• Confirm: "Session wrapped. Resume with 'resume session' next time."

When to Use

Scenario Use this skill?

Multi-phase feature spanning 2+ sessions Yes

Work that might hit context compaction Yes

Before making risky or destructive changes Yes (checkpoint first)

Quick bug fix or single-file edit No

Single-session task with clear scope No

SESSION.md Principles

• Track progress, not architecture — SESSION.md is a work log, not project documentation

• Concrete over vague — "Resume at src/auth.ts:42 , implement token refresh" beats "Continue auth work"

• Collapse completed work — finished phases become 1-2 line summaries

• Keep under 100 lines — if it's longer, collapse more aggressively

Autonomy Rules

• Just do it: Read SESSION.md, read CLAUDE.md, check git status/log, present summaries

• Brief confirmation: Creating new SESSION.md, committing WIP checkpoints

• Ask first: Overwriting an existing SESSION.md, deleting session data

Reference Files

When Read

Creating a new SESSION.md references/session-template.md

Context compaction tips, what survives references/compaction-survival.md