specflow-simulate

specflow-simulate is a skill for Claude Code, Codex from Hulupeep/Specflow. It costs 172 tokens per session (940 once invoked), scanned A, original, MIT.

A method for simulating a Specflow story with several user types and different routes before the feature is built. A Specflow story is a detailed description of intended product behavior and its acceptance conditions.

In plain words
What is it for?
Use it to test a story from different behavioral perspectives and routes. It helps improve the story before the formal audit and implementation stages.
Why use it?
It finds missing cases, edge cases, and unhandled paths that a single happy-path review may overlook. Each finding is turned into a proposed requirement, acceptance condition, scenario, or journey step.

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/hulupeep/specflow/specflow-simulate
Any agent
npx skills add Hulupeep/Specflow --skill specflow-simulate
Clone the repo
git clone --depth 1 https://github.com/Hulupeep/Specflow

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 specflow-simulate

README.md
[![agentmods](https://agentmods.dev/badge/skills/hulupeep/specflow/specflow-simulate.svg)](https://agentmods.dev/skills/hulupeep/specflow/specflow-simulate)
Your own site
<a href="https://agentmods.dev/skills/hulupeep/specflow/specflow-simulate"><img src="https://agentmods.dev/badge/skills/hulupeep/specflow/specflow-simulate.svg" alt="Measured on agentmods" height="20"></a>
Per session 172 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 940 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 $0.00172 $0.00940
Opus 5 $0.00086 $0.00470
Sonnet 5 $0.00034 $0.00188
Haiku 4.5 $0.00017 $0.00094

Measured 4d ago against content hash ef0033b37ab5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

specflow-simulate 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/specflow-simulate/SKILL.md · 43 lines

How it starts

The opening of the file, as written. The whole thing — 43 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Specflow Simulate

Run a story through realistic usage — multiple personas, multiple routes — to find the gaps and edges a single happy-path reading misses. The output is not commentary; it is a set of concrete, proposed additions that make the story sharper before any code is written.

When to run

Trigger on: "simulate this story", "simulate usage end to end", "find gaps / edges", "run personas through this", "stress-test this story", or /specflow-simulate <file-or-issue>.

Position in the Specflow flow — this runs after create, before audit:

create (specflow-writer) → SIMULATE (this skill) → audit/uplift (specflow-audit) → pre-flight gate

It is generative (discover + propose). It is NOT the pre-flight gate (that verifies and blocks). Do not conflate the two.

The method

Full method (persona archetypes, route taxonomy, gap→edit mapping, output format) is in references/simulation-method.md. Summary:

  1. Read the story (issue via gh issue view <n> --json title,body,comments, or the file). Extract the intended outcome, the actors, and the surfaces.
  2. Derive 3–5 distinct personas — not demographics; behavioural archetypes that route through the problem differently (e.g. power user, first-timer, adversarial/edge user, wrong-permissions user, interrupted/returning user). Pick the ones that stress this story.
  3. Walk each persona through the story end-to-end — the happy path AND at least one divergent route per persona: where do they get confused, blocked, take an unanticipated branch, hit an empty/error/permission state, or make a decision the story didn't plan for?
  4. Collect gaps — each gap is a concrete moment where the story is silent, ambiguous, or wrong for that persona/route.
  5. Map every gap to a story edit — a new REQ-NN, a negative-path AC, a new Gherkin scenario/branch, a new journey step + data-testid, or a flagged open question. A gap with no proposed edit is incomplete.
  6. Propose, don't silently rewrite — post the findings as ONE labelled block: a GitHub comment (gh issue comment) or an appended ## Simulation Findings (proposed) section. The user (or the subsequent specflow-audit uplift) folds accepted items into the story body. Only edit the body directly if the user explicitly says to apply.

Read the full file on GitHub · 43 lines

Files

What ships with it

1 file 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 · 43 lines · 172 tokens per session scan A ef0033b37ab5

Subscribe to this mod's changes

specflow-simulate is a skill published in the GitHub repository Hulupeep/Specflow (24 stars, last pushed 1mo ago), licensed MIT. It adds 172 tokens to every session and 940 once invoked, about $0.0009 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.