dev-days-estimate

Estimates development effort in 8-hour dev days from Notion feature specs and codebase analysis.

Updated Jul 7, 2026
One-click install
npx skills add https://github.com/Takkuya/claude-skills --skill dev-days-estimate-takkuya
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: dev-days-estimate
Source: https://github.com/Takkuya/claude-skills/tree/main/dev-days-estimate
Command: npx skills add https://github.com/Takkuya/claude-skills --skill dev-days-estimate-takkuya

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? Estimating how long a feature will take is error-prone when done from memory or a quick skim of the spec. This Skill applies Codeleap's official "Process: How to Estimate" workflow end to end: it reads the full Notion Feature Spec, checks technical specs and real code in the repository, maps the flow, surfaces hidden coupling and edge cases, and produces a justified line-item estimate in dev days (1 dev day = 8 hours). ## Core Features & Use Cases - Spec-driven estimation: Reads a Notion Feature Spec (or pasted text), classifies ambiguities as blocking questions or additive line items, and asks all blocking questions in a single round before finalizing numbers. - Codebase-grounded analysis: Explores the actual repositories per area (Mobile/Web/Backend) to confirm reuse, hidden coupling, and risks, citing real evidence instead of guessing. - Structured output across 5 areas: Always breaks work into Mobile, Web, Backend, QA, and Design line items with per-item justification, additive items, and risk buffers shown separately from the base total. - Use Case: Paste a Notion Feature Spec URL and ask "how many dev days will this take" — the Skill reads the spec, explores the code, asks clarifying questions, and returns a per-area estimate table in the chat, optionally filling the spec's Calculator database only if explicitly requested. ## Quick Start Estimate how many dev days this Notion Feature Spec will take, checking the codebase for reuse before giving me the numbers.

Frequently Asked Questions about dev-days-estimate

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I estimate dev days for a feature spec?

Provide a Notion Feature Spec URL or pasted feature text. The Skill reads the full spec, explores the relevant repositories for reuse and coupling, asks one round of blocking questions, then returns a per-area estimate table in dev days of 8 hours.

What is a dev day in this estimation process?

One dev day equals 8 hours of work by one person, calibrated to a senior developer using LLM assistance. It includes build, integration, edge-case handling, and code review — never calendar days.

Does the estimate write to Notion automatically?

No. The default deliverable is the estimate in the chat. Lines are only created in the spec's Calculator database, or Days/T-Shirt Sizing properties updated, when the user explicitly asks.

How are unknown libraries or integrations handled in estimates?

Unknown integrations are not estimated blindly. They become a separate spike line item with its own days, and the final number for that area is explicitly marked as dependent on the spike result.

When should I not use dev-days-estimate?

Do not use it to break work into execution phases (that is plan-phases) or to create the development task itself (that is create-dev-task). It only estimates effort in days, and never estimates items marked Out of Scope.