multi-phase-session

multi-phase-session is a skill for Claude Code, Codex from avizmarlon/agent-skills. It costs 43 tokens per session (1,711 once invoked), scanned A, original, MIT.

A way to manage long software efforts by giving each distinct phase its own session and recording progress in handoff files.

In plain words
What is it for?
Running phased projects, preparing handoffs, validating milestones, and starting the next phase with durable project information.
Why use it?
Long conversations can lose detail as their context fills up, while files preserve decisions, unfinished work, and acceptance criteria for the next session.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Codex.

Good fit Running phased projects, preparing handoffs, validating milestones, and starting the next phase with durable project information.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/avizmarlon/agent-skills/multi-phase-session
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add avizmarlon/agent-skills --skill multi-phase-session
Clone the repo
git clone --depth 1 https://github.com/avizmarlon/agent-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for multi-phase-session

README.md
[![agentmods](https://agentmods.dev/badge/skills/avizmarlon/agent-skills/multi-phase-session.svg)](https://agentmods.dev/skills/avizmarlon/agent-skills/multi-phase-session)
Your own site
<a href="https://agentmods.dev/skills/avizmarlon/agent-skills/multi-phase-session"><img src="https://agentmods.dev/badge/skills/avizmarlon/agent-skills/multi-phase-session.svg" alt="Measured on agentmods" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,711 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00043 $0.01711
Opus 5 $0.00022 $0.00856
Sonnet 5 $0.00009 $0.00342
Haiku 4.5 $0.00004 $0.00171

Measured 8d ago against content hash 9a8a54383fc6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

multi-phase-session scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/multi-phase-session/SKILL.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Multi-Phase Session Management

Large software projects, long-term initiatives, or phased work—where each phase is a distinct milestone with clear acceptance criteria—benefit from a session-per-phase model instead of trying to compact context within a single conversation.

Why separate sessions per phase

AI context quality degrades measurably around 60% of capacity (before auto-compact), and subsequent compacts introduce truncation and lossy summarization. A project split across multiple compact cycles accumulates error.

Better pattern:

  • One AI session per phase
  • Each phase terminates with a commit, updated handoff, and session closure
  • Next phase opens fresh with the handoff file and project docs as context source
  • The codebase, specification documents, and handoff file are the canonical context—not the previous chat history

This preserves quality because:

  • The next agent (or next session with the same agent) reads living docs, not truncated chat summaries
  • Decisions, blocked items, and state are recorded in files meant for future readers, not buried in chat
  • Each phase is independently validated before moving forward
  • Context isn't split across a "what I remember from chat" and "what the files say"

Session lifecycle per phase

Phase completion checklist

Before closing a session:

  1. Code is committed — all work merged to the appropriate branch or merged to main (per project CI rules)
  2. Acceptance criteria are met — the phase has a defined "done" state; validate it
  3. Handoff is written/updated — if the project uses session-handoff.md or equivalent, it reflects current state
  4. Next phase is clear — the handoff names the next objective, expected duration, and any blockers
  5. CHANGELOG or progress log is updated — significant milestones are recorded for future reference

Opening a new session for the next phase

  1. Read the handoff first — open session-handoff.md or equivalent in full before proceeding
  2. Check git stategit status, git branch, git log --oneline -5 to understand current state
  3. Verify acceptance criteria from prior phase — confirm the last phase actually completed and is clean
  4. Read critical docs — specification, architecture decisions (ADRs), any phase-specific README
  5. Begin with verification — first steps validate the prior phase is stable before building the next one

Read the full file on GitHub · 131 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 131 lines · 43 tokens per session scan A 9a8a54383fc6

Subscribe to this mod's changes

multi-phase-session is a skill published in the GitHub repository avizmarlon/agent-skills (2 stars, last pushed 2mo ago), licensed MIT. It adds 43 tokens to every session and 1,711 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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