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Overview

Register callback functions to be notified when agents interact with skills. Useful for logging, analytics, and custom monitoring.

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Available Callbacks

CallbackTriggered WhenArguments
on_loadAgent loads a skill’s instructionsskill_name: str, description: str
on_script_executeAgent executes a skill scriptskill_name: str, script_path: str, returncode: int
on_reference_accessAgent reads a skill referenceskill_name: str, reference_path: str

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Usage

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


def on_skill_loaded(skill_name: str, description: str):
    print(f"[SKILL LOADED] {skill_name}: {description}")


def on_script_executed(skill_name: str, script_path: str, returncode: int):
    print(f"[SCRIPT RUN] {skill_name}/{script_path} -> exit code {returncode}")


def on_reference_accessed(skill_name: str, reference_path: str):
    print(f"[REFERENCE READ] {skill_name}/{reference_path}")


skills = Skills(
    loaders=[LocalSkills("./my-skills")],
    on_load=on_skill_loaded,
    on_script_execute=on_script_executed,
    on_reference_access=on_reference_accessed,
)

agent = Agent(
    model="anthropic/claude-sonnet-4-6",
    name="Agent",
    role="Developer Assistant",
    goal="Assist with development tasks",
    skills=skills,
)

result = agent.print_do("Review this code using the code-review skill.")
# Output:
# [SKILL LOADED] code-review: Code quality analysis and best practices
# [REFERENCE READ] code-review/style-guide.md

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Error Handling

Callback exceptions are caught and logged as warnings — they never interrupt the agent’s execution: 
def buggy_callback(skill_name: str, description: str):
    raise ValueError("oops")

skills = Skills(
    loaders=[LocalSkills("./my-skills")],
    on_load=buggy_callback,  # Logs warning, doesn't crash
)