Build and Share Custom AI Skills: The k-claw Marketplace

What are AI agent skills?

A skill is a package of files and instructions that gives your AI agent a new capability. Without skills, your agent is a general-purpose assistant — smart but generic. With skills, it becomes a specialist. An agent with the SEO audit skill can analyze website structures and meta tags. An agent with the invoice generation skill can produce professional PDF invoices from conversation data.

Skills are the bridge between a capable AI model and a domain-specific tool. They turn potential into practical output.

How skills work under the hood

Every skill in k-claw is composed of two elements:

• Context files — Documents placed in the agent's working directory that provide domain knowledge, templates, formatting rules, and reference material. These files become part of the agent's permanent context.
• Personality additions — Instructions appended to the agent's system prompt that tell it how and when to use the skill. These define the behavioral patterns, output formats, and trigger conditions.

When you install a skill, k-claw uses the connector daemon to write these files to the agent's directory on your server via write_file commands. The agent picks up the new files automatically — no restart required. Removing a skill deletes the files via delete_file commands, cleanly reverting the agent to its pre-skill state.

This file-based approach means skills are transparent and auditable. You can open any skill file, read exactly what it adds to your agent, and modify it if needed.

Built-in skill packs

k-claw ships with five built-in skill packs that cover common business needs:

Skill Pack	What It Does	Best For
SEO Audit	Analyzes URLs for meta tags, heading structure, content quality, and technical SEO issues	CMO agents, content writers
Invoice Generation	Creates structured invoice data from conversation context — client name, line items, totals, tax calculations	Operations agents, admin assistants
Code Review	Reviews code snippets for bugs, security vulnerabilities, performance issues, and best practice violations	CTO agents, engineering agents
Social Media	Generates platform-specific posts (Twitter/X, LinkedIn, Instagram) with appropriate tone, length, and hashtag strategies	CMO agents, content agents
Email Drafting	Produces professional emails following customizable templates — outreach, follow-up, negotiation, support response	COO agents, support agents

Each built-in skill is installed with a single click from the agent detail page in your k-claw dashboard. Installation takes seconds — the files are written to your server, and the agent gains the new capability immediately.

Creating your own custom skill

The real power of the skills system is that anyone can create new skills. If you have domain expertise that an AI agent could benefit from, you can package it as a skill.

Step 1: Define the capability

Start by clearly describing what your skill does. Good skills are focused and specific. "General business advice" is too broad. "SaaS churn analysis from monthly metrics data" is specific enough to be useful.

Ask yourself: what files would a human expert want on their desk to do this task? Those files become your skill's context documents.

Step 2: Create context files

Write the reference documents your agent needs. These are plain text or markdown files that contain:

• Domain knowledge — Key concepts, terminology, frameworks, and methodologies
• Templates — Output formats, document structures, report layouts
• Examples — Sample inputs and expected outputs that demonstrate correct behavior
• Rules and constraints — What the agent should and should not do when using the skill

For example, a "legal contract review" skill might include files like contract-checklist.md (key clauses to verify), red-flags.md (common problematic language), and review-template.md (the expected output format).

Step 3: Write personality additions

Create the system prompt instructions that tell the agent how to use the skill. These should cover:

• When to activate the skill (trigger conditions)
• How to process input (steps and methodology)
• What output format to use
• What limitations to acknowledge

Good personality additions are clear and structured. For example: "When the user asks you to review a contract, follow the checklist in contract-checklist.md. Flag any language matching patterns in red-flags.md. Format your response using the template in review-template.md. Always include a disclaimer that this is AI-assisted analysis, not legal advice."

Step 4: Test locally

Install your skill on one of your own agents and test it extensively. Send various inputs, check edge cases, and refine the context files and personality additions until the output consistently meets your quality standards.

This iterative process is where most of the work happens. A first draft might produce 70% quality output. After a few rounds of refinement — adding missing context, clarifying instructions, improving examples — the skill reaches 90%+ quality.

Step 5: Package and share

Once your skill is tested and polished, package it for the marketplace. A skill package includes:

• A name and description
• The context files
• The personality additions
• Tags for discoverability
• A recommended agent type (which roles benefit most from this skill)

The marketplace ecosystem

The k-claw marketplace is where the community shares skills. The vision is a growing library of specialized capabilities that any k-claw user can install on their agents with a single click.

Categories currently include:

• Marketing and SEO — Content optimization, keyword research, competitor analysis
• Development — Code review, documentation generation, architecture assessment
• Business operations — Invoice handling, report generation, data analysis
• Communication — Email templates, social media, customer support scripts
• Industry-specific — E-commerce, SaaS, consulting, healthcare, legal

As the community grows, the marketplace becomes more valuable. A marketing agency can share its content grading rubric as a skill. A DevOps team can share their incident response framework. A legal firm can share their contract review checklist. Each contribution makes every agent on the platform more capable.

Installing community skills

Installing a skill from the marketplace follows the same process as built-in skills:

1. Browse the marketplace or search by category/tag
2. Read the skill description and reviews
3. Click install on the agent you want to enhance
4. The skill files are written to your server via the connector
5. Your agent gains the new capability immediately

Because skills are file-based, they are completely transparent. After installation, you can read every file the skill added to your agent. If you want to modify a skill for your specific needs — adjusting templates, adding your own examples, tweaking the personality additions — you are free to do so.

Skill composition: combining capabilities

Skills are designed to be composable. An agent can have multiple skills installed simultaneously, and they work together rather than conflicting. A CMO agent might have the SEO audit skill, the social media skill, and the email drafting skill installed at the same time.

The agent's AI model handles the integration naturally. When asked to "create a social media campaign for our new product launch and include SEO-optimized blog post outlines," the agent draws on both the social media and SEO skills to produce a comprehensive response.

However, be mindful of context window limits. Each installed skill adds files to the agent's context. With the ~1.5GB RAM per agent, you can comfortably install 5-8 skills before context overhead becomes a concern.

Skill versioning and updates

Skills evolve over time. When a skill author updates their skill — improving the context files, refining the personality additions, fixing edge cases — the updated version appears in the marketplace. You can update installed skills from the dashboard, or choose to keep your current version if you have made local modifications.

The k-claw platform tracks which version of each skill is installed on each agent through the agentSkills table, making it easy to manage skill inventories across your entire fleet.

Best practices for skill creation

Based on the patterns we see in the most effective community skills:

• Be specific — A skill that does one thing well is more valuable than a skill that does ten things poorly.
• Include examples — Agents learn more from examples than from abstract instructions. Include 3-5 input/output pairs in your context files.
• Define boundaries — Clearly state what the skill does not do. A "contract review" skill should explicitly say it does not constitute legal advice.
• Format output consistently — Use templates. Users want predictable, structured output they can rely on.
• Test with different models — A skill that works with GPT-4o should also work with Claude. Avoid model-specific prompt patterns.
• Keep files focused — Multiple small, focused context files are better than one large document. The agent can reference the relevant file for each task.

The network effect

Every skill added to the marketplace makes the entire k-claw platform more valuable. A user considering k-claw sees not just the base platform but the full library of community skills that extend its capabilities. And every new user is a potential skill creator who might contribute the exact capability someone else needs.

This is the flywheel: more users create more skills, which attract more users, who create more skills. The goal is a marketplace where any business need — from GDPR compliance checks to competitive pricing analysis to event planning workflows — has a ready-made skill that can be installed in seconds.

The skills system turns k-claw from a platform into an ecosystem. And ecosystems, once they reach critical mass, compound in value far beyond what any single product can deliver.