branch.fork

A branch copy starts from the current state of another branch. After it is created, each branch can receive changes independently.

In plain words
What is it for?
Use it to create an isolated line of work from a source branch, such as testing changes or preparing a separate dataset.
Why use it?
It lets you work from a known state without changing the original branch. Later changes on either branch remain separate.

Command

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.

agentmods
npx agentmods add commands/stratalab/strata-core/branch.fork
Clone the repo
git clone --depth 1 https://github.com/stratalab/strata-core
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 156 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00000 $0.00156
Opus 5 $0.00000 $0.00078
Sonnet 5 $0.00000 $0.00031
Haiku 4.5 $0.00000 $0.00016

Measured 2d ago against content hash 2595ef0e0878, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

branch.fork 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 2d 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.

crates/executor/idl/v1/prose/commands/branch.fork.md · 9 lines

What it actually says

Forks a new branch from the source branch's current head. The new branch sees all data visible on the source at fork time; later writes on either branch stay isolated. The returned branch summary records the parent name, fork version, and generation.

On the CLI, all three fork commands share the single verb strata branch fork <SOURCE> <BRANCH>: with no flags it runs this command, while --version routes to branch.fork_at_version and --timestamp routes to branch.fork_at_timestamp (both wire-surface commands).

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. 2d ago First seen · 9 lines · 0 tokens per session scan A 2595ef0e0878

Subscribe to this mod's changes

branch.fork is a command published in the GitHub repository stratalab/strata-core (2 stars, last pushed 2d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 156 tokens. 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.