[FEATURE] Allow resuming a conversation from an arbitrary JSONL file path

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Currently, claude --resume and claude --continue only work with sessions managed internally by Claude Code under ~/.claude/projects/. There is no way to resume a conversation from a JSONL session file located at an arbitrary path.

Proposed Solution

Add a flag (e.g., --resume-from <path>) that accepts a path to a JSONL session file and resumes the conversation from it, regardless of where the file is located.

# Resume from a shared team conversation
claude --resume-from ./team-sessions/alice/debug-build-issue.jsonl

# Resume from a backup
claude --resume-from /backups/claude-sessions/2026-03-15-session.jsonl

This would open a new session pre-populated with the conversation history from the specified file, similar to how --resume works today but without requiring the file to be in ~/.claude/projects/.

Alternative Solutions

A current workaround is to manually copy JSONL file into the appropriate ~/.claude/projects/ subdirectory and then use claude --resume. This is error-prone (the directory structure must match) and cumbersome.

Another alternative would be to extend --resume <UUID> to search additional directories (related to #5768), but that still requires files to follow Claude Code's internal directory conventions.

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

1. Suppose we have a team that works together on a Claude customization (e.g., a skill) that is version controlled.
2. For evaluation purposes, we save all Claude code conversations that use this customization in that same git repository. (For instance, with a hook that copies session JSONL files from ~/.claude/projects/ to that shared git repository at the end of each conversation.)
3. A teammate debugs an issue with the developed skill and saves the conversation to the shared repo
4. I pull the repo and want to resume that conversation to continue where they left off
5. With --resume-from, I could run claude --resume-from ./team-sessions/alice/debug-build-issue.jsonl and pick up right where my teammate left off

Additional Context

_No response_