// Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets.
| name | skill-creator |
| description | Create or update AgentSkills. Use when designing, structuring, or packaging skills with scripts, references, and assets. |
This skill provides guidance for creating effective skills.
Skills are modular, self-contained packages that extend the agent's capabilities by providing specialized knowledge, workflows, and tools. Think of them as "onboarding guides" for specific domains or tasks—they transform the agent from a general-purpose agent into a specialized agent equipped with procedural knowledge that no model can fully possess.
The context window is a public good. Skills share the context window with everything else the agent needs: system prompt, conversation history, other Skills' metadata, and the actual user request.
Default assumption: the agent is already very smart. Only add context the agent doesn't already have. Challenge each piece of information: "Does the agent really need this explanation?" and "Does this paragraph justify its token cost?"
Prefer concise examples over verbose explanations.
Match the level of specificity to the task's fragility and variability:
High freedom (text-based instructions): Use when multiple approaches are valid, decisions depend on context, or heuristics guide the approach.
Medium freedom (pseudocode or scripts with parameters): Use when a preferred pattern exists, some variation is acceptable, or configuration affects behavior.
Low freedom (specific scripts, few parameters): Use when operations are fragile and error-prone, consistency is critical, or a specific sequence must be followed.
Every skill consists of a required SKILL.md file and optional bundled resources:
skill-name/
├── SKILL.md (required)
│ ├── YAML frontmatter metadata (required)
│ │ ├── name: (required)
│ │ └── description: (required)
│ └── Markdown instructions (required)
└── Bundled Resources (optional)
├── scripts/ - Executable code (Python/Bash/etc.)
├── references/ - Documentation intended to be loaded into context as needed
└── assets/ - Files used in output (templates, icons, fonts, etc.)
Every SKILL.md consists of:
name and description fields. These are the only fields that the agent reads to determine when the skill gets used, thus it is very important to be clear and comprehensive in describing what the skill is, and when it should be used.scripts/)Executable code (Python/Bash/etc.) for tasks that require deterministic reliability or are repeatedly rewritten.
scripts/rotate_pdf.py for PDF rotation tasksreferences/)Documentation and reference material intended to be loaded as needed into context.
references/api_docs.md, references/policies.mdassets/)Files not intended to be loaded into context, but rather used within the output the agent produces.
assets/logo.png, assets/slides.pptx, assets/frontend-template/A skill should only contain essential files that directly support its functionality. Do NOT create extraneous documentation or auxiliary files, including:
The skill should only contain the information needed for an AI agent to do the job at hand.
Skills use a three-level loading system to manage context efficiently:
Keep SKILL.md body to the essentials and under 500 lines to minimize context bloat. Split content into separate files when approaching this limit.
Pattern 1: High-level guide with references
# PDF Processing
## Quick start
Extract text with pdfplumber:
[code example]
## Advanced features
- **Form filling**: See [FORMS.md](FORMS.md) for complete guide
- **API reference**: See [REFERENCE.md](REFERENCE.md) for all methods
Pattern 2: Domain-specific organization
bigquery-skill/
├── SKILL.md (overview and navigation)
└── reference/
├── finance.md (revenue, billing metrics)
├── sales.md (opportunities, pipeline)
└── product.md (API usage, features)
Pattern 3: Conditional details
# DOCX Processing
## Creating documents
Use docx-js for new documents. See [DOCX-JS.md](DOCX-JS.md).
## Editing documents
For simple edits, modify the XML directly.
**For tracked changes**: See [REDLINING.md](REDLINING.md)
Important guidelines:
Skill creation involves these steps:
Follow these steps in order, skipping only if there is a clear reason why they are not applicable.
plan-mode).Skip this step only when the skill's usage patterns are already clearly understood.
To create an effective skill, clearly understand concrete examples of how the skill will be used. For example, when building an image-editor skill, relevant questions include:
To avoid overwhelming users, avoid asking too many questions at once. Prefer 1-2 targeted questions.
Before writing the skill, plan what resources it needs:
Use the bundled initialization script:
scripts/init_skill.py <skill-name> --path <output-path>
scripts/init_skill.py <skill-name> --path <output-path> --resources scripts,references
scripts/init_skill.py <skill-name> --path <output-path> --resources scripts --examples
This creates a skill directory with a SKILL.md template and optional resource directories.
Required fields:
---
name: my-skill-name
description: >-
Clear description of what this skill does and when to use it.
Include trigger scenarios, file types, or tasks that should activate this skill.
Example: "Process and manipulate PDF files including merging, splitting, extracting text,
filling forms, or any other document tasks"
---
Keep frontmatter minimal. metadata and always are also supported when needed, but avoid adding extra fields unless they are actually required.
Write instructions for using the skill and its bundled resources.
Once development of the skill is complete, it must be packaged into a distributable .skill file. The packaging process automatically validates the skill first:
scripts/package_skill.py <path/to/skill-folder>
Optional output directory specification:
scripts/package_skill.py <path/to/skill-folder> ./dist
The packaging script will:
Validate the skill automatically, checking:
Package the skill if validation passes, creating a .skill file named after the skill (e.g., my-skill.skill) that includes all files and maintains the proper directory structure for distribution. The .skill file is a zip file with a .skill extension.
Security restriction: symlinks are rejected and packaging fails when any symlink is present.
If validation fails, the script will report the errors and exit without creating a package. Fix any validation errors and run the packaging command again.
After testing the skill, users may request improvements. Often this happens right after using the skill, with fresh context of how the skill performed.
Iteration workflow:
Plan mode — inspect context, write a markdown plan into the active workspace's `.echo-agent/plans/` directory, and do not execute the work.
Summarize or extract text/transcripts from URLs, podcasts, and local files (great fallback for "transcribe this YouTube/video").
Get current weather and forecasts (no API key required).
Search and retrieve academic papers from arXiv using their free REST API. No API key needed. Search by keyword, author, category, or ID. Combine with web_extract or the ocr-and-documents skill to read full paper content.