[DOCS] /fork documentation missing plan file isolation behavior

Documentation Type

Missing documentation (feature not documented)

Documentation Location

https://code.claude.com/docs/en/interactive-mode

Section/Topic

Built-in commands table — /fork entry; also affects the Plan Mode section in common-workflows.md

Current Documentation

interactive-mode.md documents /fork with a single table entry:

| /fork [name] | Create a fork of the current conversation at this point |

how-claude-code-works.md provides the most complete prose description of fork semantics:

"To branch off and try a different approach without affecting the original session, use the --fork-session flag: claude --continue --fork-session" "This creates a new session ID while preserving the conversation history up to that point. The original session remains unchanged."

settings.md documents the plansDirectory setting but says nothing about how plan files interact with forks.

No documentation page mentions plan file behavior when forking a conversation.

What's Wrong or Missing?

A changelog fix reveals a previously undocumented behavior: each forked conversation now has its own isolated plan file. Before the fix, forks shared the same plan file, causing plan edits in one fork to silently overwrite the other's plan.

This means users who use Plan Mode and then fork a conversation need to know that:

1. Each fork gets its own independent plan file, scoped to its session ID.
2. Edits to the plan in one fork do not affect the plan in sibling forks or the original session.
3. If a custom plansDirectory is configured, the isolation guarantee extends to that directory.

None of this is documented in interactive-mode.md, how-claude-code-works.md, common-workflows.md, or settings.md. The Plan Mode documentation in common-workflows.md (which covers Shift+Tab, --permission-mode plan, Ctrl+G to edit the plan) makes no mention of what happens to plan files when the session is forked.

Suggested Improvement

In interactive-mode.md

Expand the /fork table entry to note plan isolation:

| /fork [name] | Create a fork of the current conversation. Each fork receives its own independent plan file — edits to one fork's plan do not affect other forks or the original session. |

In how-claude-code-works.md or common-workflows.md

Add a note under the fork/Plan Mode sections:

Plan file isolation: When you fork a session that has an active plan, each fork gets its own plan file. Changes to the plan in one fork are isolated from sibling forks and the original session. This applies whether you use /fork interactively or --fork-session from the CLI.

Impact

Medium - Makes feature difficult to understand

Additional Context

Affected Pages:

| Page | Context |
|------|---------|
| https://code.claude.com/docs/en/interactive-mode | /fork table entry — no plan file mention |
| https://code.claude.com/docs/en/common-workflows | Plan Mode section — no fork interaction documented |
| https://code.claude.com/docs/en/how-claude-code-works | Fork semantics prose — no plan file mention |
| https://code.claude.com/docs/en/settings | plansDirectory setting — no fork isolation note |

Total scope: 4 pages affected

Source: Changelog v2.1.71

Exact changelog entry:

"Fixed forked conversations (/fork) sharing the same plan file, which caused plan edits in one fork to overwrite the other"