sfd-v2

sfd-v2 is a skill for Claude Code, Codex from pyros-projects/limitless. It costs 113 tokens per session (6,613 once invoked), scanned A, original, MIT.

A planning method that helps shape an app, tool, workflow, or other project result before choosing its technical design.

In plain words
What is it for?
Use it to prototype and refine products, APIs, command-line tools, automations, policies, curricula, and other plans before development.
Why use it?
It makes the intended result clear before implementation begins, reducing the risk of building the wrong thing or leaving requirements unclear.

Skill for Claude CodeCodex

Part of the limitless plugin — 10 skills shipped together

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/pyros-projects/limitless/sfd-v2
Any agent
npx skills add pyros-projects/limitless --skill sfd-v2
Clone the repo
git clone --depth 1 https://github.com/pyros-projects/limitless

Made for: Claude Code, Codex.

Or install limitless, the plugin that ships this one along with the rest of its 10 skills.

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 sfd-v2

README.md
[![agentmods](https://agentmods.dev/badge/skills/pyros-projects/limitless/sfd-v2.svg)](https://agentmods.dev/skills/pyros-projects/limitless/sfd-v2)
Your own site
<a href="https://agentmods.dev/skills/pyros-projects/limitless/sfd-v2"><img src="https://agentmods.dev/badge/skills/pyros-projects/limitless/sfd-v2.svg" alt="Measured on agentmods" height="20"></a>
Per session 113 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,613 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 $0.00113 $0.06613
Opus 5 $0.00056 $0.03306
Sonnet 5 $0.00023 $0.01323
Haiku 4.5 $0.00011 $0.00661

Measured 4d ago against content hash 18dce6010cf8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sfd-v2 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.

plugins/limitless/skills/sfd-v2/SKILL.md · 430 lines

How it starts

The opening of the file, as written. The whole thing — 430 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Surface-First Development

Reference

If anything in this skill feels unclear, underspecified, or in tension with a real project situation, stop and read references/whitepaper-v0.6.md before improvising. Treat that whitepaper as the authoritative reference for the methodology — EXCEPT for contract derivation and handoff (Phases 4.5–5.5, Gates 1–2): this is the docket-emitting SFD v2 variant, and for everything contract-shaped, references/contract-emission.md supersedes the whitepaper's v0.6 wording. The whitepaper describes prose contract derivation; this variant emits machine-admissible contract YAML.

Triggers

  • User says "let's build", "I want an app/tool/CLI/API that...", "I have an idea for..."
  • User describes a product, feature, or tool without specifying architecture or internals
  • User wants to converge a requirements document, knowledge tree/graph, policy/rule set, curriculum, argument outline, workflow map, or other artifact before implementation
  • User says "surface first", "click dummy", "show me what it would look like", "prototype this"
  • User says "SFD", "surface-first"
  • User wants to start a new project or feature and hasn't locked in a tech approach yet
  • User asks "how should this work?" or "what would the UX be?" or "what would the workflow look like?"

Purpose

You are following the Surface-First Development methodology. The core principle: always start by building and iterating the outermost artifact the steering human can evaluate cheaply, converge it with the user, derive contracts, then build inward.

Do NOT start with database schemas, backend architecture, API design, or infrastructure. Start with what the user will actually see, touch, type, read, review, navigate, or sign.

What Counts as a Surface

The surface is the outermost artifact the steering human can evaluate cheaply. A UI is one instance. So is a requirements document, a knowledge graph, a policy, an argument outline, a curriculum, a workflow map, or a contract clause set. The binding constraints are concreteness and legibility to whoever steers — not clickability, visualness, or software-ness.

Read the full file on GitHub · 430 lines

Files

What ships with it

3 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 · 430 lines · 113 tokens per session scan A 18dce6010cf8

Subscribe to this mod's changes

sfd-v2 is a skill published in the GitHub repository pyros-projects/limitless (9 stars, last pushed 22d ago), licensed MIT. It adds 113 tokens to every session and 6,613 once invoked, about $0.0006 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.