feasibility-study

feasibility-study is a skill for Claude Code, Codex from sd0xdev/sd0x-harness. It costs 53 tokens per session (1,783 once invoked), scanned A, original, MIT.

A feasibility analysis that compares possible solutions before detailed technical planning. It examines whether each option is workable, how much effort it needs, its risks, and its future maintenance cost.

In plain words
What is it for?
Use it to ask whether something is possible, compare technical approaches, assess risks, or decide what to build before writing a technical specification.
Why use it?
It helps you choose an approach before implementation begins, when changing direction is still relatively easy. The result includes a quantitative comparison and recommendation.

Skill for Claude CodeCodex

Part of the sd0x-dev-flow plugin — 98 skills, 16 agents, 5 hooks 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/sd0xdev/sd0x-harness/feasibility-study
Any agent
npx skills add sd0xdev/sd0x-harness --skill feasibility-study
Clone the repo
git clone --depth 1 https://github.com/sd0xdev/sd0x-harness

Made for: Claude Code, Codex.

Or install sd0x-dev-flow, the plugin that ships this one along with the rest of its 98 skills, 16 agents, 5 hooks.

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 feasibility-study

README.md
[![agentmods](https://agentmods.dev/badge/skills/sd0xdev/sd0x-harness/feasibility-study.svg)](https://agentmods.dev/skills/sd0xdev/sd0x-harness/feasibility-study)
Your own site
<a href="https://agentmods.dev/skills/sd0xdev/sd0x-harness/feasibility-study"><img src="https://agentmods.dev/badge/skills/sd0xdev/sd0x-harness/feasibility-study.svg" alt="Measured on agentmods" height="20"></a>
Per session 53 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,783 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 $0.00053 $0.01783
Opus 5 $0.00026 $0.00892
Sonnet 5 $0.00011 $0.00357
Haiku 4.5 $0.00005 $0.00178

Measured 4d ago against content hash 9c207de4a0c8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

feasibility-study 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.

skills/feasibility-study/SKILL.md · 181 lines

How it starts

The opening of the file, as written. The whole thing — 181 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Feasibility Study Skill

Supplementary Agent

For each solution option, dispatch background exploration:

Agent({ description: "Explore feasibility of solution option", subagent_type: "feasibility-analyst", prompt: Research the feasibility of: <solution description> Evaluate technical feasibility, effort, risk, extensibility, and maintenance cost. })

Trigger

  • Keywords: feasibility, is this possible, can we, should we, explore options, before tech spec

When NOT to Use

  • Already have a tech spec (use /deep-analyze)
  • Need implementation, not analysis (use /codex-implement)
  • Quick question (use /codex-explain or /codex-architect)

Workflow

Resolve → Decompose → Constraints → Code research → Solutions → Codex discussion → Decision → Report

Phase 0: Resolve the feature context

The sets Phase 1 reads have to come from somewhere, and this skill is invoked directly (/feasibility-study <topic>) as often as it is invoked from another skill — so it resolves them itself rather than assuming a caller supplied them:

# The shim over the wrapper. This skill grants `Bash(bash:*)` and no node permission, and the rule
# is that a skill names the entrypoint it is permitted to run — which is also why the shared
# algorithm reference is deliberately not linked from here: it teaches the node entrypoint, and a
# file of commands this skill cannot execute has no business in its reachable graph.
bash scripts/resolve-feature.sh [--feature <key>]

The reply is one JSON document. What this skill reads out of it: scan_error first — the gate below decides whether anything else in the payload means what it says — then current_authority (what the system does today) and the design_records entries — design records carry the rationale; it is the type: requirements subset of them that states what was asked for, which is why Phase 1 filters before it selects. Each entry is { file, type, namespace, confidence, is_canonical, role }, file relative to docs_path. An empty or non-JSON reply is a failure too — node may be unavailable, which the shim cannot report as a payload. Treat it exactly as scan_error !== false below.

Read the full file on GitHub · 181 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 · 181 lines · 53 tokens per session scan A 9c207de4a0c8

Subscribe to this mod's changes

feasibility-study is a skill published in the GitHub repository sd0xdev/sd0x-harness (188 stars, last pushed yesterday), licensed MIT. It adds 53 tokens to every session and 1,783 once invoked, about $0.0003 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 2026-08-30.

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