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What Are Skills?

Skills are self-contained packages of domain expertise that extend what your agents can do. Each skill provides:
  • Instructions — detailed guidance the agent follows (loaded from SKILL.md)
  • Scripts — executable code templates the agent can run or read
  • References — supporting documentation (style guides, API docs, cheatsheets)
  • Assets — supporting files like templates, fonts, and icons
Agents discover skills progressively: they see summaries upfront and load full details on demand via tool calls — keeping context lean.

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Quick Start

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Skills on an Agent

from upsonic import Agent
from upsonic.skills import Skills, LocalSkills

agent = Agent(
    model="anthropic/claude-sonnet-4-6",
    name="Code Reviewer",
    role="Senior Developer",
    goal="Review code for quality and best practices",
    skills=Skills(loaders=[LocalSkills("./my-skills")]),
)

result = agent.print_do("Review this Python function for bugs and style issues.")

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Skills on a Task

Attach skills to a specific task instead of the agent. The agent uses them only for that task. 
from upsonic import Agent, Task
from upsonic.skills import Skills, BuiltinSkills

agent = Agent(
    model="anthropic/claude-sonnet-4-6",
    name="Writer",
    role="Content Writer",
    goal="Create clear, engaging content",
)

task = Task(
    description="Summarize this technical document in 3 bullet points.",
    skills=Skills(loaders=[BuiltinSkills(skills=["summarization"])]),
)

result = agent.print_do(task)

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Skills on a Team

Skills attached to a Team propagate to all member agents automatically. Each agent gets independent metrics. 
from upsonic import Agent, Task, Team
from upsonic.skills import Skills, BuiltinSkills

analyst = Agent(
    model="anthropic/claude-sonnet-4-6",
    name="Data Analyst",
    role="Data Analysis Expert",
    goal="Analyze data and extract insights",
)

writer = Agent(
    model="anthropic/claude-sonnet-4-6",
    name="Report Writer",
    role="Business Report Specialist",
    goal="Create professional summaries",
)

team = Team(
    agents=[analyst, writer],
    skills=Skills(loaders=[BuiltinSkills(skills=["data-analysis", "summarization"])]),
    mode="coordinate",
    model="anthropic/claude-sonnet-4-6",
)

task = Task(description="Analyze Q4 sales trends and write an executive summary.")
result = team.print_do(tasks=task)

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How It Works

When an agent runs with skills:
  1. System prompt injection — skill summaries (name, description, available scripts/references) are added to the agent’s system prompt
  2. Tool registration — four tool functions are registered so the agent can access skill content on demand
  3. Progressive loading — the agent decides when to load full instructions, read references, or run scripts
The four skill tools available to the agent:
ToolPurpose
get_skill_instructions(skill_name)Load the full instructions for a skill
get_skill_reference(skill_name, reference_path)Read a specific reference document
get_skill_script(skill_name, script_path, execute)Read or execute a script
get_skill_asset(skill_name, asset_path)Read an asset file (template, font, icon)
When skills are on both Agent and Task, tool names are automatically prefixed (task_get_skill_*) to avoid collisions. The agent decides which scope to use.

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Built-in Skills

Upsonic ships with ready-to-use skills:
SkillDescription
code-reviewStructured code reviews with severity-classified feedback, security audits, and language-specific pattern detection
summarizationMulti-format summarization (executive, technical, research, meeting, changelog) with templates
data-analysisStatistical data analysis with cleaning, exploration, visualization, and hypothesis testing
from upsonic.skills import Skills, BuiltinSkills

# Load all built-in skills
skills = Skills(loaders=[BuiltinSkills()])

# Load specific ones
skills = Skills(loaders=[BuiltinSkills(skills=["code-review"])])

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Skill Sources

Load skills from multiple sources:
LoaderSource
LocalSkills(path)Local filesystem directory
BuiltinSkills()Bundled with Upsonic
InlineSkills(skills)Programmatically defined Skill objects
GitHubSkills(repo)GitHub repository
URLSkills(url)Remote URL (zip/tar)
from upsonic.skills import Skills, LocalSkills, GitHubSkills, BuiltinSkills

skills = Skills(loaders=[
    BuiltinSkills(skills=["code-review"]),
    LocalSkills("./company-skills"),
    GitHubSkills(repo="myorg/shared-skills", branch="main"),
])
Later loaders override earlier ones when skill names conflict.

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Next Steps