decompact

See everything your coding agent forgot.

When Claude Code compacts a conversation or you rewind it, the earlier messages vanish from the app. They're still in log files on your disk, though. decompact reads those files and gives you your whole history back as a fast, searchable local web page.

npx decompact

Why

Compaction keeps a long session going, but the agent and the app both lose the details: why you made a decision, the error you already fixed, the approach you rewound away. People keep asking for a way to get that back (#27242, #3138). The data was never deleted, only hidden. decompact shows it.

• Recovers compacted context. Everything above a compaction is shown and labeled, along with the summary the agent was left with.
• Shows rewound branches. Prompts you edited or rewound away stay next to the path you took.
• Searches across every session. It covers every project, every prompt and every answer.
• Works with Claude Code and Codex CLI. Subagent transcripts are linked from the tool call that started them.
• Exports to Markdown. Attach a full transcript to a bug report or keep it in your notes.
• Shares one session as a single HTML file. Common secrets (API keys, tokens, passwords) and your home folder path are redacted.
• Claude Code plugin. /decompact:recall lets Claude read what compaction hid from the session you're in.
• Private by design. No server, no account, no network. It writes static HTML to ~/.decompact, and nothing leaves your machine.

Usage

npx decompact                  # build the site and open it
npx decompact list             # sessions, newest first
npx decompact open 3f2a        # open one session by id prefix
npx decompact export 3f2a > session.md
npx decompact share 3f2a       # one HTML file you can send to someone

Use latest instead of an id for the newest session. Add --project <text> to get the newest session in one project.

Option	What it does
--source claude / --source codex	Only one agent
--project <text>	Only sessions whose folder contains <text>
--out <dir>	Write the site somewhere other than ~/.decompact
--no-open	Build without opening a browser
export --branches	Include rewound branches
export --main-only	Leave out compacted messages
export --thinking	Include thinking blocks
export --no-tools	Leave out tool calls
export --compacted-only	Only the messages compaction hid
share -o <file>	Where to write the shared page (default decompact-<id>.html)
share --no-redact	Keep secrets and paths as they are

share takes the same --main-only, --branches, --thinking and --no-tools flags as export. Redaction catches common key and token formats, not everything, so skim the file before you send it.

Claude Code plugin

claude plugin marketplace add hjk-sys/agentlog
claude plugin install decompact@decompact

Command	What it does
/decompact:recall [topic]	Claude reads the compacted part of the current session and answers from it. Claude also uses it on its own when you ask about something it no longer remembers.
/decompact:open	Builds the history site and opens it
/decompact:share	Saves the current session as one redacted HTML file

It reads ~/.claude/projects (or $CLAUDE_CONFIG_DIR) and ~/.codex/sessions (or $CODEX_HOME). Point it elsewhere with --claude-dir and --codex-dir. It needs Node.js 18 or newer.

How it works

Claude Code appends every event to a JSONL file and never deletes from it. Each entry has a uuid and a parentUuid, so the file is a tree:

• The live conversation is the path from the newest entry back to the root.
• A rewind or edit starts a new child from an earlier message, so the old path stays in the file as a dead branch.
• A compaction writes a compact_boundary entry that cuts the parent link but keeps a logicalParentUuid, so everything before it is still reachable.

decompact walks that tree and labels each message as live, compacted or rewound. Codex rollouts are a flat list with compacted markers, handled the same way.

Library

import { loadSessions, toMarkdown } from 'decompact';

for (const s of loadSessions({ sources: ['claude'] })) {
  console.log(s.title, s.compactions, s.branches);
}

Contributing

Log formats change between agent versions. If a session renders wrong, please open an issue with your agent version and, if you can, a redacted snippet of the log.

npm install
npm test
node scripts/demo-data.mjs /tmp/demo   # made-up sessions for trying changes
CLAUDE_CONFIG_DIR=/tmp/demo/claude CODEX_HOME=/tmp/demo/codex node dist/cli.js

License

MIT