Bring Test-First Planning to Your Agent with plan-feature

Where this fits

A developer opens a repo and says to their agent: 'plan this' or 'how should we implement this?'. Without a structured workflow, the agent may respond with vague bullet points or jump straight to code. This skill gives the agent a concrete test-first planning orchestration: check plan mode, classify the task as feature/spec change, then produce implementation steps with tests in mind before any code is written.

Why agents benefit

• Performs an explicit plan-mode gate first. If ExitPlanMode is in the deferred tools list, the skill stops and asks the user to enter plan mode, preventing silent misuse.
• Standardizes task type checks. The agent distinguishes feature/spec changes from bug investigations, and can ask for more detail instead of generating an off-target plan.
• Enforces a test-first sequence. The planning output naturally includes test cases and acceptance criteria, which later guides implementation and review.
• Reduces hallucinated scaffolding. The skill loads a narrow set of orchestration rules instead of letting the agent improvise a plan from generic memory.
• Makes plans reproducible. Every invocation follows the same workflow, so users can compare plan quality across sessions and teach the agent one consistent process.

Practical scenarios

'Plan this' for a new feature

The user is in plan mode and points at a GitHub issue. The skill loads, confirms the task is a feature request, and organizes the plan around failing tests first, then the minimal implementation and verification steps.

Spec change on an existing module

The user says 'we are changing the shipping calculation spec'. The skill classifies this as a spec change and drives the agent to restate the changed behavior, identify existing tests that need updating, and outline a test-first migration path.

Agent interrupted mid-planning

The user toggles plan mode off while the skill is active. On the next step, the skill notices ExitPlanMode is back in the deferred tools list, stops, and asks for plan mode to be re-enabled before continuing.

Add it to your agent workflow

Install it in an agent project:

npx skills add nowsprinting/unity-coding-skills --skill plan-feature

Then, with plan mode active, give the skill a short spec argument:

npx skills run plan-feature 'Add a discount code field to the checkout form'

The agent will load the workflow only when it is safe to call ExitPlanMode, verify the task type, and produce a test-first plan before any implementation starts. For a broader catalog of this skill and similar ones, see the OpenAgentSkill entry: https://www.openagentskill.com/skills/nowsprinting-plan-feature.

Compare before adopting

Before adding plan-feature, compare it with alternatives.

• Quality signals: Does the skill describe concrete workflow steps and mode checks, or is it just a prompt template?
• Maintenance freshness: Check the repository for recent commits, issue responses, and whether it is actively used by the author's own Unity projects.
• Alternatives: Look for other plan-mode skills that fit your agent runtime, or in-house workflows already covering test-first planning.
• Workflow fit: The skill is written for Unity development context, but its orchestration pattern is mostly language-agnostic; confirm it matches your assistant's plan-mode conventions and file-generation format before relying on it.

Why it is worth tracking

This skill is a small but well-defined automation package: it encodes a specific workflow and enforces it through a mode check, which is a useful pattern for any agent team. With only 19 stars, it is not a mainstream choice, but the maintenance signal matters more: the author has a history of Unity coding skills, and the plan-feature skill is narrow enough to evaluate in an afternoon. Track it when you are building a test-first planning loop and want a concrete reference for how an agent should behave when the user simply says plan this.