fire-number

fire-number is a cursor rule for Cursor from mohitagw15856/pm-claude-skills. It costs 98 tokens per session (967 once invoked), scanned A, original, MIT.

A financial-independence calculator that estimates the savings target and time needed to reach it. Financial independence means having enough invested money to support planned spending without relying on work income.

In plain words
What is it for?
Use it to estimate a FIRE target, project years to reach it, and compare outcomes under different savings and investment assumptions.
Why use it?
It shows how the answer changes with investment returns and withdrawal rates instead of presenting one overly precise retirement date. It also names risks such as taxes and market downturns.

Cursor rule for Cursor

Written for Cursor: a Cursor rule (.mdc).

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is python3 scripts/fire_number.py --savings 120000 --monthly 3000 --spend 60000.

Good fit Use it to estimate a FIRE target, project years to reach it, and compare outcomes under different savings and investment assumptions.

Compare 6 cursor rules from other repositories ↓
About the project

PM Skills is a collection of plain-Markdown instructions that teach AI assistants structured methods for handling professional, personal, and life-admin tasks. People use it with Claude, ChatGPT, Gemini, Cursor, Codex, and other supported agents for work such as writing product requirements, reviewing documents, or planning difficult situations.

mohitagw15856/pm-claude-skills · 1,357 stars · on GitHub · mohitagw15856.github.io

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/mohitagw15856/pm-claude-skills
agentmods
npx agentmods add rules/mohitagw15856/pm-claude-skills/fire-number

Made for: Cursor.

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 fire-number

README.md
[![agentmods](https://agentmods.dev/badge/rules/mohitagw15856/pm-claude-skills/fire-number/github.svg)](https://agentmods.dev/rules/mohitagw15856/pm-claude-skills/fire-number)
Your own site
<a href="https://agentmods.dev/rules/mohitagw15856/pm-claude-skills/fire-number"><img src="https://agentmods.dev/badge/rules/mohitagw15856/pm-claude-skills/fire-number/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for fire-number

Your own site · 80×15
<a href="https://agentmods.dev/rules/mohitagw15856/pm-claude-skills/fire-number"><img src="https://agentmods.dev/badge/rules/mohitagw15856/pm-claude-skills/fire-number.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 98 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 967 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00098 $0.00967
Opus 5 $0.00049 $0.00483
Sonnet 5 $0.00020 $0.00193
Haiku 4.5 $0.00010 $0.00097

Measured 8d ago against content hash 69dee084e535, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

fire-number 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 8d 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.

exports/cursor/pm-calculators/fire-number/fire-number.mdc · 79 lines

How it starts

The opening of the file, as written. The whole thing — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FIRE Number Skill

Every FIRE calculation is three assumptions wearing a number's clothing: a withdrawal rate, a real return, and the pretense that returns arrive in a convenient order. This skill does the math properly and refuses the false precision — the deliverable is a surface of outcomes with the assumptions labeled, not a single date to organize a life around.

What This Skill Produces

  • The FIRE number — annual spend ÷ withdrawal rate, with the withdrawal rate named as the choice it is
  • Years to target — at stated savings, contributions, and real return
  • The sensitivity grid — years-to-target across return (3/5/7%) × withdrawal rate (3/3.5/4%)
  • The ignored-risks list — sequence-of-returns, taxes, spending drift — stated, not buried

Required Inputs

Ask for these if not provided:

  • Current invested savings (invested — not home equity, not emergency cash)
  • Monthly contribution (realistic, not aspirational — ask which)
  • Target annual spend in retirement (today's dollars; if unknown, current spend is the honest starting guess, labeled)
  • Return and withdrawal assumptions (defaults: 5% real, 4% withdrawal — both labeled as defaults)

Programmatic Helper

python3 scripts/fire_number.py --savings 120000 --monthly 3000 --spend 60000
python3 scripts/fire_number.py --savings 120000 --monthly 3000 --spend 60000 --return 5 --wr 4 --json

Deterministic monthly compounding at a constant real return (inflation already removed — never stack an inflation adjustment on top). The script prints the sensitivity grid and its own not-modeled list.

Framework: The Honesty Rules

  • The 4% rule is a study, not a law — one country, one era, 30-year horizons; early retirees have longer horizons, which is why the grid includes 3% and 3.5%
  • Sequence risk is unmodeled and largest near the finish — a crash in year 1 of retirement ≠ a crash in year 20; say this every time
  • Real vs nominal discipline — everything here is in today's dollars; mixing in nominal market returns (~+3%) silently is the classic error
  • A range is the deliverable — "17–24 years depending on returns" is honest; "August 2043" is astrology with a spreadsheet

Read the full file on GitHub · 79 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. 8d ago First seen · 79 lines · 98 tokens per session scan A 69dee084e535

Subscribe to this mod's changes

fire-number is a cursor rule published in the GitHub repository mohitagw15856/pm-claude-skills (1,357 stars, last pushed today), licensed MIT. It adds 98 tokens to every session and 967 once invoked, about $0.0005 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 2026-09-03.