implement

A command that carries out planned coding work on separate Git worktrees, then combines the results on an integration branch. A worktree is an additional working copy of the same repository.

In plain words
What is it for?
Use it when a saved fable-flow plan has multiple tracks to implement and merge.
Why use it?
It coordinates several implementation tracks in parallel and checks the combined changes afterward.

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/jjilli/fable-flow/implement
Clone the repo
git clone --depth 1 https://github.com/jjilli/fable-flow
Per session 42 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 558 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 $0.00042 $0.00558
Opus 5 $0.00021 $0.00279
Sonnet 5 $0.00008 $0.00112
Haiku 4.5 $0.00004 $0.00056

Measured yesterday against content hash d3c6c3442fd0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

implement 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 yesterday.

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.

commands/implement.md · 26 lines

How it starts

The opening of the file, as written. The whole thing — 26 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Context

  • Branch: !git branch --show-current
  • Working tree: !git status --porcelain | head -20

Your job

Run the Implement and Merge phases of the fable-flow pipeline from the saved plan.

Input: $ARGUMENTS (--base REF overrides the plan's base)

Preconditions: .fable-flow/plan.md exists (otherwise stop and point the user at /fable-flow:plan), and the working tree is clean (otherwise stop and tell the user what's uncommitted — never stash or discard their work yourself).

  1. Read the plan. BASE_SHA = the plan's recorded base (or --base). SLUG = from .fable-flow/task.md, else derive from the plan title.
  2. Spawn one fable-flow:implementer per track, all in a single message so they run concurrently — each already gets its own isolated worktree. Each prompt carries, inline: its full track manifest, the entire Contracts section, the conventions digest (.fable-flow/explore-conventions.md), any relevant lessons from .fable-flow/memory/lessons/ (worktree subagents can't read .fable-flow/ themselves), BASE_SHA, and branch slug fable-flow/<SLUG>-t<n>. Remind it: reset to BASE_SHA first, touch only owned files, commit before reporting. Save reports to .fable-flow/track-<n>-report.md.
  3. Merge: git checkout -b fable-flow/<SLUG> <BASE_SHA>, then git merge --no-ff each track branch in the plan's merge order. Conflicts resolve in favor of the plan's Contracts. Run the plan's Integration verification commands; fix small breakage directly, or spawn an implementer with a fix manifest based on the integration branch's current SHA for anything larger.
  4. Clean up merged track worktrees (git worktree remove, paths from the reports) and delete merged fable-flow/<SLUG>-t* branches.

Report with evidence: branch, tracks merged, the actual verification output, any deviations the implementers recorded, and anything blocked. If tests fail, say so with the output — don't proceed silently. Point the user at /fable-flow:review as the next step.

Read the full file on GitHub · 26 lines

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. yesterday First seen · 26 lines · 42 tokens per session scan A d3c6c3442fd0

Subscribe to this mod's changes

implement is a command published in the GitHub repository jjilli/fable-flow (2 stars, last pushed 1mo ago), licensed MIT. It adds 42 tokens to every session and 558 once invoked, about $0.0002 per session on Opus 5. 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.