A command that creates a technical specification for a game feature or system. A technical specification explains how a feature should fit into the existing code, dependencies, tests, and architecture.

Use it before building a game feature to document its design, affected code, dependencies, testing approach, and implementation details.

It reduces guesswork before implementation by connecting the proposed feature to current project patterns and integration points.

tech-spec — Command for coding agents by sponticelli: A command that creates a technical specification for a…

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 commands/sponticelli/gamedev-claude-plugins/tech-spec

Clone the repo

git clone --depth 1 https://github.com/sponticelli/gamedev-claude-plugins

Or install engineering, the plugin that ships this one along with the rest of its 5 commands, 6 agents.

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.

README.md

[![agentmods](https://agentmods.dev/badge/commands/sponticelli/gamedev-claude-plugins/tech-spec.svg)](https://agentmods.dev/commands/sponticelli/gamedev-claude-plugins/tech-spec)

Your own site

<a href="https://agentmods.dev/commands/sponticelli/gamedev-claude-plugins/tech-spec"><img src="https://agentmods.dev/badge/commands/sponticelli/gamedev-claude-plugins/tech-spec.svg" alt="Measured on agentmods" height="20"></a>

Per session 14 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 606 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.

Model	Per session	Once invoked
Fable 5	$0.00014	$0.00606
Opus 5	$0.00007	$0.00303
Sonnet 5	$0.00003	$0.00121
Haiku 4.5	$0.00001	$0.00061

Measured 5d ago against content hash 124f57f3d3e4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

tech-spec 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 5d 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.

plugins/engineering/commands/tech-spec.md · 116 lines

How it starts

The opening of the file, as written. The whole thing — 116 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Technical Specification Generator

Create a tech spec for implementing a game feature.

Context Gathering

Before generating the tech spec, understand the existing codebase:

Analyze Existing Architecture

List source directories and their apparent purpose
Identify existing patterns (ECS, component-based, MVC, etc.)
Check for existing tech documentation or architecture notes
Note code style conventions (naming, structure)

Understand Dependencies

Read package/dependency files (package.json, Cargo.toml, *.csproj)
Identify external services or APIs in use
Note any middleware (networking, audio, UI frameworks)

Check Testing Setup

Look for test frameworks and existing tests
Identify testing patterns used in the codebase
Check for CI/CD configuration

Identify Related Code

Find similar features already implemented
Look for patterns that should be followed
Note any shared utilities or base classes

Use this context to:

Match the tech spec to existing patterns
Reference the right base classes and utilities
Suggest realistic locations for new code
Identify integration points accurately

Output Format

# Technical Spec: [Feature Name]

## Overview
**Purpose:** [What this implements]
**Design Doc Reference:** [Link to GDD section if applicable]
**Estimated Complexity:** [Low/Medium/High]

## Requirements

### Functional
- [What it must do]

### Non-Functional
- Performance: [Frame budget, memory limits]
- Platform: [Target platforms]
- Dependencies: [What it relies on]

## Architecture

### Components
| Component | Responsibility | Location |
|-----------|---------------|----------|
| [Name] | [What it does] | [Where in codebase] |

### Data Structures
```[language]
// Key data structures with comments

Interfaces

// Public interfaces

Flow

[How data/control flows through the system]

Implementation Plan

Phase 1: Foundation

[Core functionality]

[Task]
[Task]

Phase 2: Features

[Additional capabilities]

[Task]
[Task]

Phase 3: Polish

[Final touches]

[Task]
[Task]

Edge Cases

[Scenarios that need special handling]

Testing Strategy

Unit tests: [What to test]
Integration tests: [What to verify]
Manual tests: [Playtesting scenarios]

Risks & Mitigations

Risk	Likelihood	Impact	Mitigation
[Risk]	[L/M/H]	[L/M/H]	[How to address]

Open Questions

[Decisions that need to be made]

Read the full file on GitHub · 116 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.

5d ago First seen · 116 lines · 14 tokens per session scan A 124f57f3d3e4

Subscribe to this mod's changes

tech-spec is a command published in the GitHub repository sponticelli/gamedev-claude-plugins (15 stars, last pushed 7mo ago), licensed MIT. It adds 14 tokens to every session and 606 once invoked, about $0.0001 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.

Game development Planning

tech-spec