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janjaali/janjaali-agent-plugin

v1.0.0MIT

Reusable, agent-agnostic skills: general code and markdown conventions, Scala development conventions, and a spec-driven development workflow.

GitHub

Agent Plugin

A single, agent-agnostic Agent Plugin — an open, vendor-neutral package format for reusable AI agent components. This plugin bundles a set of Agent Skills, each covering one convention or workflow, so any Agent Plugins-compatible client (GitHub Copilot, or others) can discover and load them consistently.

Installing

GitHub Copilot CLI

Copilot CLI is deprecating direct repo/URL/path plugin installs in favor of marketplace-based installs, so register this repository as a marketplace first, then install the plugin from it:

copilot plugin marketplace add janjaali/agent-plugin
copilot plugin install janjaali-agent-plugin@janjaali-agent-plugin

.github/plugin/marketplace.json is what makes marketplace add work — it's a Copilot CLI-specific discovery file, not part of the Agent Plugins specification (see Why marketplace.json? below). Its single entry points at . (the repository root), since this repository is one plugin, not a catalog of several.

Other Agent Plugins-compatible clients

Any client that implements the Agent Plugins specification can load this repository directly as a plugin — point it at the repository root, where plugin.json lives.

Skills

  • skills/code-development — general conventions for markdown and code (skills/code-development/references/): uppercase markdown filenames, no hard-wrapped prose, structure, doc comments, why-comments, ~80-column line widths, and no trailing commas.
  • skills/git-development — git conventions for agents (skills/git-development/references/): the agent commits and pushes only when asked (staging only the files it modified), and commit messages have a period-terminated subject plus a detailed body.
  • skills/scala-development — Scala conventions (skills/scala-development/references/) for test structure, file hygiene, sequence literal style, exhaustive pattern matching, HOCON comment syntax, and validation object return types.
  • skills/spec-driven-development — a spec-driven development workflow producing SPEC.md and companion documents (DESIGN.md, DOMAIN.md, DATABASE.md, KAFKA.md, CONVENTIONS.md).

Repository structure

plugin.json                       # Agent Plugins manifest ($schema: https://agent-plugins.org/schemas/1.0.0/plugin.schema.json)
skills/<skill-name>/SKILL.md      # Skill definition (YAML frontmatter: name, description)
skills/<skill-name>/...           # Optional supporting files (for example, references/ with ADRs for code-development, git-development and scala-development)
.github/plugin/marketplace.json   # Copilot CLI marketplace wrapper, not part of the Agent Plugins spec

This repository is a single plugin, not a marketplace of plugins — plugin.json sits at the repository root and every skill is a subdirectory of skills/.

Adding or changing a skill

  1. Add a subdirectory under skills/<skill-name>/ with a SKILL.md file (YAML frontmatter with name and description, followed by the skill's instructions).
  2. Keep the description specific enough that a client can determine when the skill applies.
  3. Put supporting files in a references/ subfolder next to the skill's SKILL.md, and link each from SKILL.md with a one-line summary. Write every reference as an ADR named with a skill-specific prefix and number (for example CODE-0001-..., SCALA-0001-..., GIT-0001-...).
  4. Follow the code-development skill's conventions in this repository too — for example, avoid hard-wrapping markdown prose.

Why marketplace.json?

The Agent Plugins specification defines only the portable plugin package itself (plugin.json, skills/, mcp.json); it explicitly leaves distribution, installation, and discovery to each client. A marketplace index format isn't standardized yet — it's an open, unresolved proposal in the spec's own discussion tracker. .github/plugin/marketplace.json here exists solely so GitHub Copilot CLI can register and browse this repository as a marketplace ahead of its removal of direct repo installs; it has no bearing on the plugin's portability or spec conformance.