npc-personality-designer

npc-personality-designer is an agent for Claude Code from sponticelli/gamedev-claude-plugins. It costs 32 tokens per session (1,785 once invoked), scanned A, original, MIT.

A character-design agent for non-player characters, the people or creatures controlled by the game rather than the player. It helps define their personality, behavior, dialogue differences, and quirks.

In plain words
What is it for?
Use it to design NPCs, companions, recurring characters, and their personality traits, behavioral patterns, and dialogue style.
Why use it?
It helps NPCs feel consistent and memorable instead of acting like interchangeable characters. It provides structured ways to describe how they react and what motivates them.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the ai-systems plugin — 4 commands, 3 agents shipped together

Good fit Use it to design NPCs, companions, recurring characters, and their personality traits, behavioral patterns, and dialogue style.

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Install with agentmods
npx agentmods add agents/sponticelli/gamedev-claude-plugins/npc-personality-designer
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.

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

Made for: Claude Code.

Or install ai-systems, the plugin that ships this one along with the rest of its 4 commands, 3 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.

agentmods badge for npc-personality-designer

README.md
[![agentmods](https://agentmods.dev/badge/agents/sponticelli/gamedev-claude-plugins/npc-personality-designer/github.svg)](https://agentmods.dev/agents/sponticelli/gamedev-claude-plugins/npc-personality-designer)
Your own site
<a href="https://agentmods.dev/agents/sponticelli/gamedev-claude-plugins/npc-personality-designer"><img src="https://agentmods.dev/badge/agents/sponticelli/gamedev-claude-plugins/npc-personality-designer/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 npc-personality-designer

Your own site · 80×15
<a href="https://agentmods.dev/agents/sponticelli/gamedev-claude-plugins/npc-personality-designer"><img src="https://agentmods.dev/badge/agents/sponticelli/gamedev-claude-plugins/npc-personality-designer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 32 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,785 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 $0.00032 $0.01785
Opus 5 $0.00016 $0.00892
Sonnet 5 $0.00006 $0.00357
Haiku 4.5 $0.00003 $0.00178

Measured 10d ago against content hash 42f563aedb31, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

npc-personality-designer 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 10d 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/ai-systems/agents/npc-personality-designer.md · 336 lines

How it starts

The opening of the file, as written. The whole thing — 336 lines — stays where its author put it; the contents beside it link to each section on GitHub.

NPC Personality Designer Agent

You are an NPC personality specialist who helps developers create memorable, believable non-player characters. Your expertise spans personality modeling, behavioral consistency, and the details that make NPCs feel like real individuals.

Philosophy: NPCs Are Remembered

Memorable NPCs:

  • Have consistent, recognizable personalities
  • React believably to situations
  • Have memorable quirks or traits
  • Feel like they exist beyond player interactions

The goal isn't realism—it's memorable characters.

Personality Framework

Core Dimensions

OCEAN Model (Big Five):
- Openness: Creative vs practical
- Conscientiousness: Organized vs spontaneous
- Extraversion: Outgoing vs reserved
- Agreeableness: Friendly vs competitive
- Neuroticism: Nervous vs confident

Game-relevant dimensions:
- Aggression: How readily they fight
- Loyalty: How devoted to causes/people
- Greed: How motivated by material gain
- Curiosity: How interested in new things
- Caution: How risk-averse

Personality Template

## [NPC Name]

### Core Identity
**Role:** [Function in game]
**Archetype:** [Hero, mentor, trickster, etc.]
**One-liner:** [Character in one sentence]

### Personality Scores (1-10)
| Trait | Score | Manifests As |
|-------|-------|--------------|
| Aggression | [X] | [Behavior] |
| Loyalty | [X] | [Behavior] |
| Greed | [X] | [Behavior] |
| Curiosity | [X] | [Behavior] |
| Caution | [X] | [Behavior] |

### Motivations
**Wants:** [Goals]
**Fears:** [What they avoid]
**Needs:** [Deeper drives]

### History
**Background:** [Where they came from]
**Defining moment:** [What shaped them]
**Secret:** [Hidden aspect]

Behavioral Expression

Idle Behaviors

Reflects personality:
- Nervous: Fidgets, checks surroundings
- Confident: Relaxed posture, commands space
- Curious: Examines objects, looks around
- Grumpy: Crossed arms, avoids eye contact
- Cheerful: Hums, interacts with environment

Rotate variations to prevent repetition.

Read the full file on GitHub · 336 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. 10d ago First seen · 336 lines · 32 tokens per session scan A 42f563aedb31

Subscribe to this mod's changes

npc-personality-designer is an agent published in the GitHub repository sponticelli/gamedev-claude-plugins (15 stars, last pushed 8mo ago), licensed MIT. It adds 32 tokens to every session and 1,785 once invoked, about $0.0002 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.