# project-estimation

A skill that helps the agent estimate project scope, timeline and resources. Useful when you need a budget or a plan you can defend.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 659 installs · ★ 371
- Author: aj-geddes
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/aj-geddes/useful-ai-prompts/tree/HEAD/skills/project-estimation/SKILL.md
- Updated: 2026-03-04
- HTML: https://affpapa.org/en/nevibecode/skills/project-estimation

## What it does

The skill hands the agent several estimation techniques: bottom-up, top-down, analogous and three-point (PERT). Reference guides live in the `references/` directory and cover PERT, bottom-up, analogous estimation, resource estimation and templates. There is also a Python example with the PERT formula `(O + 4M + P) / 6`, standard deviation and a confidence interval.

The agent runs more than one method and compares the results. The guidance calls for a contingency buffer of 15-25% on new projects. It also says to include planning, testing and deployment in the estimate, not just coding.

Estimating without a clear scope definition produces garbage, so pin down the project boundaries first. The skill does not supply historical data from your past projects. Without it, analogous estimation leans on whatever you tell the agent.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add aj-geddes/useful-ai-prompts --skill project-estimation -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/project-estimation/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/project-estimation/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add aj-geddes/useful-ai-prompts --skill project-estimation -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/project-estimation/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add aj-geddes/useful-ai-prompts --skill project-estimation -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/project-estimation/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install aj-geddes/useful-ai-prompts project-estimation
```

2. **Manually: put the files in place**
- File: `.github/skills/project-estimation/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add aj-geddes/useful-ai-prompts --skill project-estimation -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/aj-geddes/useful-ai-prompts --path skills/project-estimation
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/project-estimation/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add aj-geddes/useful-ai-prompts --skill project-estimation -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/aj-geddes/useful-ai-prompts/tree/HEAD/skills/project-estimation/SKILL.md

## When to use it
- estimate a project timeline with three methods and compare them
- add a risk buffer to a new project budget
- break a large effort into parts and estimate each one
- explain to a client where the number in the plan came from
- re-estimate after the scope changes

## Example prompts
- Estimate the timeline for this module using PERT and bottom-up
- Work out the project budget with a contingency buffer
- Compare analogous and three-point estimates for this feature

## Source text · SKILL.md · MIT

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BEGIN THIRD-PARTY FILE 19125ddc6f31d1c5
````text
---
name: project-estimation
description: >
  Estimate project scope, timeline, and resource requirements using multiple
  estimation techniques including bottom-up, top-down, and analogous estimation
  methods for accurate project planning.
---

# Project Estimation

## Table of Contents

- [Overview](#overview)
- [When to Use](#when-to-use)
- [Quick Start](#quick-start)
- [Reference Guides](#reference-guides)
- [Best Practices](#best-practices)

## Overview

Accurate project estimation determines realistic timelines, budgets, and resource allocation. Effective estimation combines historical data, expert judgment, and structured techniques to minimize surprises.

## When to Use

- Defining project scope and deliverables
- Creating project budgets and timelines
- Allocating team resources
- Managing stakeholder expectations
- Assessing project feasibility
- Planning for contingencies
- Updating estimates during project execution

## Quick Start

Minimal working example:

```python
# Three-point estimation technique for uncertainty

class ThreePointEstimation:
    @staticmethod
    def calculate_pert_estimate(optimistic, most_likely, pessimistic):
        """
        PERT formula: (O + 4M + P) / 6
        Weighted toward most likely estimate
        """
        pert = (optimistic + 4 * most_likely + pessimistic) / 6
        return round(pert, 2)

    @staticmethod
    def calculate_standard_deviation(optimistic, pessimistic):
        """Standard deviation for risk analysis"""
        sigma = (pessimistic - optimistic) / 6
        return round(sigma, 2)

    @staticmethod
    def calculate_confidence_interval(pert_estimate, std_dev, confidence=0.95):
        """
        Calculate confidence interval for estimate
        95% confidence ≈ ±2 sigma
        """
        z_score = 1.96 if confidence == 0.95 else 2.576
// ... (see reference guides for full implementation)
```

## Reference Guides

Detailed implementations in the `references/` directory:

| Guide | Contents |
|---|---|
| [Three-Point Estimation (PERT)](references/three-point-estimation-pert.md) | Three-Point Estimation (PERT) |
| [Bottom-Up Estimation](references/bottom-up-estimation.md) | Bottom-Up Estimation |
| [Analogous Estimation](references/analogous-estimation.md) | Analogous Estimation |
| [Resource Estimation](references/resource-estimation.md) | Resource Estimation |
| [Estimation Templates](references/estimation-templates.md) | Estimation Templates |

## Best Practices

### ✅ DO

- Use multiple estimation techniques and compare results
- Include contingency buffers (15-25% for new projects)
- Base estimates on historical data from similar projects
- Break down large efforts into smaller components
- Get input from team members doing the actual work
- Document assumptions and exclusions clearly
````
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