Transcript and logs

Each run leaves a trail in its folder:

File	Written by	Content	Redacted
transcript.jsonl	the transcript logger hook	every tool call and result, as JSON lines	yes
session.log	the chat	what the terminal showed, as plain text	no
conversation.jsonl, subagents/*.jsonl	the run store	the SDK's full transcript	no

transcript.jsonl

A PreToolUse and a PostToolUse hook append one line per event:

{"ts":"2026-09-29T10:15:02.114Z","event":"pre_tool_use","tool":"WebFetch","input":{"url":"https://example.com","prompt":"Summarize"}}
{"ts":"2026-09-29T10:15:04.870Z","event":"post_tool_use","tool":"WebFetch","result":"Example Domain. This domain is for use in illustrative examples…"}

• The file is created on the first tool call; a session without tool calls has none.
• Long results are cut at 2,000 characters, and base64 payloads (screenshots) are replaced by [image omitted, N bytes base64], so a browser agent's transcript stays readable.
• Every line is redacted before it's written: each value in config.secrets, and CLAUDE_CODE_OAUTH_TOKEN always, become ***.

const password = await readPasswordFromVault();

const config: Config = {
  mode: "guided",
  projectDir,
  password,
  secrets: [password, process.env.SHOP_API_KEY!],
};

Redaction replaces exact values. A secret the model reformats (splits, encodes, quotes differently) won't match; keep secrets out of the agent's reach with deniedPaths and by not putting them in prompts.

createTranscriptLogger(path, secrets) and summarizeToolResponse() are exported for sessions assembled by hand.

session.log

The chats mirror what the terminal shows into the run's session.log: the welcome message, each line typed, the agent's replies, [action] lines for tool calls, notices and errors, without colors. It's the easiest way to read what happened in a run. It isn't redacted: it contains whatever was typed and replied.

The SDK's transcript

With a runs folder, the SDK's own transcript (every message, tool input and tool result, in full) is kept in the run folder so the conversation can be resumed. The CLI also keeps its copy in ~/.claude/projects/. Neither is redacted.

aviso

Treat run folders as sensitive: keep them out of version control and backups you share.