Subagent

Plugin Developer

Main thread configuration for Claude Code plugin development sessions. Optimized for creating, validating, and improving plugins in the night-market ecosystem. Use via: claude --agent plugin-developer Or set in .claude/settings.json: { "agent": "plugin-developer" }

Type: Subagent
Repository: athola/claude-night-market
GitHub stars: 339
License: MIT
Repo last updated: Sep 24, 2026
Source file: .claude/agents/plugin-developer.md
Model: sonnet

What Plugin Developer is

Plugin Developer is a subagent published in the athola/claude-night-market repository on GitHub, which has about 339 stars. The repository describes itself as: “23 Claude Code plugins: TDD enforcement hooks, git/PR workflows, spec-driven development, code review, project lifecycle, fix-from-error, maintenance automation, context optimization, research, and multi-LLM delegation. 186 skills, 128 commands, 54 agents.”

A subagent is a specialist assistant that Claude can hand part of a task to. It is a markdown file whose frontmatter sets a name, a description that tells Claude when to delegate, and optionally the tools and model it may use; the body becomes the subagent's own system prompt.

Because a subagent works in its own context, it keeps the main conversation focused: Claude can send a narrow job, such as a review or a specialised analysis, to Plugin Developer and get back a compact result.

It is set up to use these tools: Read, Write, Edit, Bash, Glob, Grep, Task, WebFetch, WebSearch. Limiting tools is a good sign: the subagent can only do what those tools allow.

How to install Plugin Developer

Claude Code

Download plugin-developer.md from the repository.
Save it to ~/.claude/agents/ to use it in every project, or to .claude/agents/ inside one project to share it through version control.
Claude Code watches these folders, so the subagent is usually available right away. Ask Claude to use it by name, or @-mention it to make sure it runs.

Claude Cowork

Cowork loads subagents through plugins. If the repository is packaged as a plugin marketplace, add it under Customize → Plugins → Add marketplace and install the plugin that contains this subagent.
Otherwise, bundle the file into your own plugin's agents/ folder and upload it from Customize → Plugins.

New to extending Cowork? Our plugins guide and Customize guide explain how skills, plugins, and connectors fit together.

Inside the source file

An excerpt from .claude/agents/plugin-developer.md, shared under the repository's MIT license. Read the full file on GitHub.

You are in plugin development mode for the claude-night-market ecosystem.

Context

This is a Claude Code plugin marketplace containing multiple plugins:

abstract - Meta-skills for plugin/skill development
conserve - Context and token optimization
imbue - Review methodologies and evidence logging
memory-palace - Knowledge management and digital gardens
parseltongue - Python development expertise
pensive - Code review specializations
sanctum - Git workflow and documentation
spec-kit - Specification-driven development

Primary Focus

Validation First: Always validate plugin structure before making changes
Skill Quality: Follow modular skill patterns with proper frontmatter
Agent Design: Use appropriate model escalation and tool restrictions
Documentation: Keep READMEs and CHANGELOG updated

Available Subagents

Delegate specialized work to:

abstract:plugin-validator - Validate plugin structure
abstract:skill-auditor - Audit skill quality
pensive:code-reviewer - Review code changes

Development Workflow

Understand existing patterns in the target plugin
Follow the established conventions
Validate changes with abstract:validate-plugin
Test any Python code with parseltongue agents
Update documentation as needed

Before you install

Read the whole file first. Skills, commands, and subagents are instructions Claude will follow, so make sure they match what you want.
Check which tools, scripts, or MCP servers it uses. Local servers and scripts run with your permissions.
Try it in a test project or a copy of your files before pointing it at real work.
Pin the version you tested, and review changes before updating.
Watch for instructions that fetch web content or run shell commands; those are where prompt injection risks start. See our prompt injection guide.

FAQ

What is Plugin Developer?

Plugin Developer is a subagent for Claude Code and Claude Cowork from the athola/claude-night-market repository on GitHub. Main thread configuration for Claude Code plugin development sessions. Optimized for creating, validating, and improving plugins in the night-market ecosystem. Use via: claude --agent plugin-developer Or set in .claude/settings.json: { "agent": "plugin-developer" }

How do I install Plugin Developer in Claude Code?

Download plugin-developer.md from the repository. Save it to ~/.claude/agents/ to use it in every project, or to .claude/agents/ inside one project to share it through version control. Claude Code watches these folders, so the subagent is usually available right away. Ask Claude to use it by name, or @-mention it to make sure it runs.

Can I use Plugin Developer in Claude Cowork?

Cowork loads subagents through plugins. If the repository is packaged as a plugin marketplace, add it under Customize → Plugins → Add marketplace and install the plugin that contains this subagent. Otherwise, bundle the file into your own plugin's agents/ folder and upload it from Customize → Plugins.

Is Plugin Developer safe to install?

It is a third-party community resource, not reviewed by Anthropic or this site. Read the source file first, check which tools and connectors it uses, and install only from sources you trust.

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Listing data comes from the public GitHub repository and was last checked in September 2026. Excerpts are © their authors and shared under MIT. This directory is independent and not affiliated with Anthropic or the resource's authors.