feature-flow

feature-flow is a skill for Claude Code, Codex from tienenwu/fables. It costs 35 tokens per session (1,171 once invoked), scanned A, original, MIT.

A process for handling risky software changes that affect public interfaces, data formats, shared connections between parts of a system, releases, authentication, payments, or production data.

In plain words
What is it for?
Use it to plan and review high-risk features, schema changes, migrations, releases, and cross-layer data flows where mistakes could affect other systems or real users.
Why use it?
It makes important design choices, risks, contracts, rollback needs, and verification limits explicit before implementation begins.

Skill for Claude CodeCodex

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 skills/tienenwu/fables/feature-flow
Any agent
npx skills add tienenwu/fables --skill feature-flow
Clone the repo
git clone --depth 1 https://github.com/tienenwu/fables

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for feature-flow

README.md
[![agentmods](https://agentmods.dev/badge/skills/tienenwu/fables/feature-flow.svg)](https://agentmods.dev/skills/tienenwu/fables/feature-flow)
Your own site
<a href="https://agentmods.dev/skills/tienenwu/fables/feature-flow"><img src="https://agentmods.dev/badge/skills/tienenwu/fables/feature-flow.svg" alt="Measured on agentmods" height="20"></a>
Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,171 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 $0.00035 $0.01171
Opus 5 $0.00017 $0.00585
Sonnet 5 $0.00007 $0.00234
Haiku 4.5 $0.00003 $0.00117

Measured 4d ago against content hash 21f4108a857a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

feature-flow 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 4d 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.

en/feature-flow/SKILL.md · 93 lines

How it starts

The opening of the file, as written. The whole thing — 93 lines — stays where its author put it; the contents beside it link to each section on GitHub.

🌐 繁體中文(canonical) · English mirror

feature-flow — Harness high-risk-feature Profile

Core Principles

This skill supplies spec/design/implementation techniques and artifact templates for high-risk features. When Harness exists, Harness owns risk routing, state transitions, evidence, and contract lifecycle. This skill never creates a second state machine.

Without Harness, use the same profile after creating a risk assessment and one artifact root: docs/plans/<slug>/.

When to Use

Use for public APIs, schemas, shared integration points, cross-layer data flow, migrations, releases, auth/payments/production data, or features with both costly ambiguity and rollback.

Do not use merely because many files change. Low-risk mechanical changes use quick/standard. If design has no material tradeoff and no absolute escalation trigger, return to the risk router and downgrade.

Profile States

1. Discovery / Risk

Add Risk Assessment to plan.md: matched absolute high-risk triggers, why quick conditions do not all hold, matching contracts, reusable patterns, external side effects, and verification limits. Do not total numeric scores.

File count records blast radius but never selects the profile alone.

2. Spec

Create spec.md: Why, in/out scope, GIVEN-WHEN-THEN AC, assumptions, non-goals, and rollback conditions.

Ask the user only for costly ambiguity, product/scope tradeoffs, public contracts, irreversible actions, or external side effects. Decide reversible internals and record assumptions.

UI/UX ambiguity requires a mockup, walkthrough, or annotated screenshot before implementation.

3. Design / Plan

Create plan.md: architecture/data flow, Key Decisions, interfaces, migration/rollback, phases, phase acceptance, and planned evidence for every AC.

Every phase must be independently verifiable. Split phases that span unrelated risk surfaces. Prefer established adjacent patterns over generic design.

Read the full file on GitHub · 93 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 4d ago First seen · 93 lines · 35 tokens per session scan A 21f4108a857a

Subscribe to this mod's changes

feature-flow is a skill published in the GitHub repository tienenwu/fables (4 stars, last pushed 1mo ago), licensed MIT. It adds 35 tokens to every session and 1,171 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.