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SergeyMenshykh 1d94518f37 Python: Add ClassSkill for class-based skill definitions (#5678)
* Python: Add ClassSkill for class-based skill definitions

Add ClassSkill abstract base class with decorator-based resource and script
discovery, porting .NET's AgentClassSkill (PRs #5027 and #5183) to Python.

- Add ClassSkill(Skill, ABC) with instructions abstract property, cached
  content/resources/scripts properties
- Add @ClassSkill.resource and @ClassSkill.script static method decorators
  for auto-discovery of methods and properties
- Extract _build_skill_content() and _create_resource_element() shared
  helpers from InlineSkill for reuse
- Add _discover_marked_members() for scanning class hierarchies
- Add _make_method_name() for Python-to-skill name conversion
- Add class_based_skill sample (UnitConverterSkill)
- Update mixed_skills sample with TemperatureConverterSkill
- Add 58 new tests covering ClassSkill, decorator discovery, property
  resources, inheritance, kwargs forwarding, and duplicate detection
- Export ClassSkill from agent_framework public API

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: replace try/except/continue with assignment to satisfy bandit B112

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* address PR review feedback

- Walk cls.__mro__ in _discover_marked_members for inherited property resources
- Use inspect.getattr_static for MRO-aware is_property check
- Return defensive copies from resources/scripts properties
- Raise TypeError on wrong decorator stacking order (@resource above @property)
- Log warning instead of silently swallowing descriptor errors during discovery
- Validate explicit name= at decoration time via _validate_member_name
- Add tests for all of the above

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix temperature converter skill: make resource necessary for script

Refactor TemperatureConverterSkill so the agent must read the
formulas resource (factor/offset) before calling the script,
aligning with the volume-converter pattern.

- Resource: numeric factor/offset table instead of symbolic formulas
- Script: generic linear transform (value * factor + offset)
- Instructions: updated to reflect new workflow

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-05-07 19:39:12 +00:00

5.0 KiB

Mixed Skills — Code, Class, and File Skills

This sample demonstrates how to combine code-defined skills, class-based skills, and file-based skills in a single agent using SkillsProvider.

Concepts

Concept Description
Code skill A Skill created in Python with @skill.script decorators for in-process callable functions and @skill.resource for dynamic content
Class skill A self-contained skill class extending ClassSkill, bundling instructions, resources, and scripts
File skill A skill discovered from a SKILL.md file on disk, with reference documents and executable script files
script_runner A callable (sync or async) satisfying the SkillScriptRunner protocol — required when file skills have scripts
SkillsProvider Registers code-defined, class-based, and file-based skills in a single provider

Skills in This Sample

volume-converter (code skill)

Defined entirely in Python code using decorators:

  • @skill.resourceconversion-table: gallons↔liters conversion factors
  • @skill.scriptconvert: converts a value using a multiplication factor

Code scripts run in-process — no subprocess or external runner needed.

temperature-converter (class skill)

Defined as a TemperatureConverterSkill class extending ClassSkill:

  • @ClassSkill.resourcetemperature-conversion-formulas: °F↔°C↔K formulas
  • @ClassSkill.scriptconvert-temperature: converts between temperature scales

Class-based scripts run in-process — no subprocess or external runner needed.

unit-converter (file skill)

Discovered from skills/unit-converter/SKILL.md:

  • Reference: references/CONVERSION_TABLES.md — supported unit conversions and their factors
  • Script: scripts/convert.py — converts a value using a multiplication factor (e.g. miles to kilometers)

File scripts are executed as local Python subprocesses via the script_runner callback.

How It Works

┌─────────────────────────────────────────────────────────────┐
│  SkillsProvider(                                            │
│    DeduplicatingSkillsSource(                               │
│      AggregatingSkillsSource([                              │
│        FileSkillsSource("./skills",       # file skills     │
│            script_runner=runner),                            │
│        InMemorySkillsSource([                               │
│            volume_skill,                  # code skill      │
│            temp_converter,                # class skill     │
│        ]),                                                  │
│      ])                                                     │
│    )                                                        │
│  )                                                          │
└─────────────┬───────────────────────────────────────────────┘
              │
              ▼
┌─────────────────────────────────────────────────────────────┐
│  script_runner(skill, script, args)                          │
│                                                             │
│  • Code scripts (@skill.script) → in-process call           │
│  • Class scripts (@ClassSkill.script) → in-process call     │
│  • File scripts (scripts/*.py) → subprocess via             │
│    the callback function                                    │
└─────────────────────────────────────────────────────────────┘

Prerequisites

Set environment variables (or create a .env file):

FOUNDRY_PROJECT_ENDPOINT=https://your-project.openai.azure.com/
AZURE_OPENAI_MODEL=gpt-4o-mini

Authenticate with Azure CLI:

az login

Running the Sample

cd python
uv run samples/02-agents/skills/mixed_skills/mixed_skills.py

Directory Structure

mixed_skills/
├── mixed_skills.py                # Main sample — wires code + file skills together
├── README.md
└── skills/
    └── unit-converter/            # File-based skill (discovered from SKILL.md)
        ├── SKILL.md
        ├── references/
        │   └── CONVERSION_TABLES.md
        └── scripts/
            └── convert.py

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