Schema errors in marketplace.json and plugin.json prevent installation in Claude Code 2.1

[imtylervo]

Hi, thanks for publishing this collection — the skills/commands are useful. Ran into two schema validation errors when trying to install via Claude Code 2.1.117. Sharing the exact errors + fixes so anyone else hitting this has a reference.

Bug 1 — .claude-plugin/marketplace.json fails schema validation

Reproduce

claude plugin marketplace add Owl-Listener/ai-design-skills

Error

✘ Failed to add marketplace: Failed to parse marketplace file at .../marketplace.json: Invalid schema:
  name: Marketplace name cannot contain spaces. Use kebab-case (e.g., "my-marketplace"),
  owner: Invalid input: expected object, received undefined,
  plugins.0: Invalid input: expected object, received string,
  plugins.1: Invalid input: expected object, received string,
  plugins.2: Invalid input: expected object, received string,
  plugins.3: Invalid input: expected object, received string,
  plugins.4: Invalid input: expected object, received string,
  plugins.5: Invalid input: expected object, received string

Root cause

Current marketplace.json:

{
  "name": "AI Design Skills Collection",
  "description": "...",
  "plugins": ["model-interaction-design", "ai-alignment-reasoning", ...]
}

The current Claude Code marketplace schema requires:

• name in kebab-case (no spaces)
• owner object (required)
• plugins array of objects, each with {name, source, description?} — bare strings are rejected

Suggested fix

{
  "name": "ai-design-skills",
  "description": "Agentic skills, commands, and plugins for designing AI products — from interaction patterns to alignment, evaluation, agent orchestration, and prompt architecture.",
  "owner": {
    "name": "Owl-Listener",
    "url": "https://github.com/Owl-Listener"
  },
  "plugins": [
    { "name": "model-interaction-design", "source": "./model-interaction-design", "description": "Patterns and skills for designing model interactions." },
    { "name": "ai-alignment-reasoning", "source": "./ai-alignment-reasoning", "description": "Skills focused on alignment and reasoning evaluation." },
    { "name": "system-behavior-shaping", "source": "./system-behavior-shaping", "description": "Techniques to shape system-level behavior via prompts/skills." },
    { "name": "evaluation", "source": "./evaluation", "description": "Evaluation skills and commands for AI products." },
    { "name": "design-agent-orchestration", "source": "./design-agent-orchestration", "description": "Patterns for multi-agent orchestration design." },
    { "name": "prompt-architecture", "source": "./prompt-architecture", "description": "Skills and commands for structuring production prompts." }
  ]
}

---

Bug 2 — Each <plugin>/.claude-plugin/plugin.json fails on install

Reproduce

After patching marketplace.json locally and re-adding:

claude plugin install model-interaction-design@ai-design-skills

Error

Validation errors: commands: Invalid input, skills: Invalid input

(Same error for all 6 plugins.)

Root cause

Each plugin.json currently contains:

{
  "name": "model-interaction-design",
  "description": "...",
  "skills": "../skills",
  "commands": "../commands"
}

Two problems:

1. The skills / commands keys aren't accepted by the current schema (expected types mismatch).
2. Even if they were, the paths ../skills and ../commands point outside the plugin directory — but each plugin dir already contains skills/ and commands/ as siblings of .claude-plugin/, so the paths are also wrong.

Suggested fix

Claude Code auto-discovers skills/ and commands/ subdirectories of the plugin root — the fields aren't needed at all. Compare to the official plugins (e.g. anthropics/claude-plugins-official → hookify/plugin.json) which only declare name, description, version, author.

Simply remove both keys:

{
  "name": "model-interaction-design",
  "description": "Design how humans and AI models communicate — conversation patterns, turn-taking, mixed-initiative flows, and generative UI."
}

Apply to all 6 plugin.json files.

---

Verification

After applying both fixes locally, all 6 plugins install cleanly:

Installing plugin "model-interaction-design@ai-design-skills"...✔ Successfully installed
Installing plugin "ai-alignment-reasoning@ai-design-skills"...✔ Successfully installed
Installing plugin "system-behavior-shaping@ai-design-skills"...✔ Successfully installed
Installing plugin "evaluation@ai-design-skills"...✔ Successfully installed
Installing plugin "design-agent-orchestration@ai-design-skills"...✔ Successfully installed
Installing plugin "prompt-architecture@ai-design-skills"...✔ Successfully installed

Happy to send a PR if that helps — just wanted to flag the issue first in case the schema mismatch is intentional for another tool.

Environment: Claude Code 2.1.117 on Ubuntu 24.04.