Python: Add MCP-based skills discovery (McpSkillsSource) (#6169)

* Add MCP-based skills discovery (McpSkill, McpSkillsSource, McpSkillResource)

Implement Agent Skills discovery over MCP following the SEP-2640 convention:
- McpSkillsSource: reads skill://index.json to discover skills served by an MCP server
- McpSkill: lazily fetches SKILL.md content via resources/read on demand
- McpSkillResource: wraps MCP resource results (text and binary)
- Path traversal protection in get_resource for defense in depth
- Samples for Foundry Toolbox and standalone MCP skills server
- Comprehensive unit tests (514 lines)

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

* Address PR review comments: rename to MCP* convention, fix error handling and samples

- Rename McpSkill/McpSkillResource/McpSkillsSource to MCPSkill/MCPSkillResource/MCPSkillsSource
- Add data-URI prefix stripping for blob resource decoding
- Let non-McpError exceptions propagate from get_resource()
- Fix contradictory test comment
- Use interactive input() in mcp_based_skill sample
- Remove misleading sample output block

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

* Restore debug logging for McpError in get_resource()

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

* Use AzureCliCredential in Foundry toolbox skills sample for consistency

Replace DefaultAzureCredential with AzureCliCredential to match the
credential convention used in all other samples.

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

* Use MCPStreamableHTTPTool in MCP skills sample

Replace raw mcp library imports (ClientSession, streamable_http_client)
with the framework's MCPStreamableHTTPTool to keep MCP server connections
consistent regardless of whether skills are enabled.

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

* Branch on McpError.error.code so only not-found errors return empty

Previously _try_read_index() and get_resource() swallowed every McpError
as 'no skills available', making auth failures, server crashes, and
connection drops indistinguishable from a server that simply has no
skills.

Now only two codes are treated as not-found:
- -32002 (MCP-spec Resource not found)
- -32601 (METHOD_NOT_FOUND — server lacks resources/read)

All other McpError codes and non-McpError exceptions propagate with a
warning log, surfacing real failures visibly.

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

* Add tests for non-McpError and non-not-found error propagation in MCP skills

Cover the re-raise branch in MCPSkill.get_resource for plain
ConnectionError/TimeoutError, the generic McpError (code 0) propagation
on get_resource, and TimeoutError propagation in _try_read_index.

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

* Revert "Use MCPStreamableHTTPTool in MCP skills sample"

This reverts commit f31ed0ded9.

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

* Introduce MCP_SKILLS experimental feature for MCP skill classes

Add a separate MCP_SKILLS feature ID to ExperimentalFeature enum and
use it for MCPSkillResource, MCPSkill, and MCPSkillsSource, since their
promotion timeline is partly outside of our control.

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

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
This commit is contained in:
semenshi-m
2026-06-03 19:09:50 +01:00
committed by GitHub
Unverified
parent a982428916
commit c6951c21f6
9 changed files with 1333 additions and 0 deletions
@@ -0,0 +1,667 @@
# Copyright (c) Microsoft. All rights reserved.
"""Tests for MCP-based skills (MCPSkillsSource, MCPSkill, MCPSkillResource)."""
from __future__ import annotations
import base64
import json
from unittest.mock import AsyncMock
import pytest
from mcp.shared.exceptions import McpError
from mcp.types import (
BlobResourceContents,
ErrorData,
ReadResourceResult,
TextResourceContents,
)
from pydantic import AnyUrl
from agent_framework import MCPSkill, MCPSkillResource, MCPSkillsSource
from agent_framework._skills import _parse_mcp_skill_index
# ---------------------------------------------------------------------------
# Fixtures & helpers
# ---------------------------------------------------------------------------
SAMPLE_SKILL_MD = """\
---
name: unit-converter
description: Convert between common units.
---
# Unit Converter
Body content here.
"""
SAMPLE_SKILL_INDEX = json.dumps(
{
"$schema": "https://schemas.agentskills.io/discovery/0.2.0/schema.json",
"skills": [
{
"name": "unit-converter",
"type": "skill-md",
"description": "Convert between common units.",
"url": "skill://unit-converter/SKILL.md",
}
],
}
)
def _make_text_result(text: str, uri: str = "skill://test") -> ReadResourceResult:
"""Create a ReadResourceResult with a single TextResourceContents."""
return ReadResourceResult(
contents=[TextResourceContents(uri=AnyUrl(uri), text=text, mimeType="text/markdown")]
)
def _make_blob_result(
data: bytes,
uri: str = "skill://test",
mime_type: str = "application/octet-stream",
) -> ReadResourceResult:
"""Create a ReadResourceResult with a single BlobResourceContents."""
return ReadResourceResult(
contents=[BlobResourceContents(uri=AnyUrl(uri), blob=base64.b64encode(data).decode(), mimeType=mime_type)]
)
def _make_empty_result() -> ReadResourceResult:
"""Create a ReadResourceResult with no contents."""
return ReadResourceResult(contents=[])
def _make_client(**read_resource_responses: ReadResourceResult) -> AsyncMock:
"""Create a mock ClientSession whose read_resource returns different results per URI.
Args:
**read_resource_responses: Mapping of URI string to ReadResourceResult.
Any URI not in this mapping raises McpError with the MCP-spec
"Resource not found" code (-32002).
"""
client = AsyncMock()
async def _read_resource(uri: AnyUrl) -> ReadResourceResult:
uri_str = str(uri)
if uri_str in read_resource_responses:
return read_resource_responses[uri_str]
raise McpError(error=ErrorData(code=-32002, message=f"Resource not found: {uri_str}"))
client.read_resource = AsyncMock(side_effect=_read_resource)
return client
# ---------------------------------------------------------------------------
# _parse_mcp_skill_index tests
# ---------------------------------------------------------------------------
class TestParseMCPSkillIndex:
"""Tests for the _parse_mcp_skill_index helper."""
def test_parses_valid_index(self) -> None:
index = _parse_mcp_skill_index(SAMPLE_SKILL_INDEX)
assert index.schema == "https://schemas.agentskills.io/discovery/0.2.0/schema.json"
assert len(index.skills) == 1
assert index.skills[0].name == "unit-converter"
assert index.skills[0].type == "skill-md"
assert index.skills[0].url == "skill://unit-converter/SKILL.md"
def test_parses_empty_skills_array(self) -> None:
index = _parse_mcp_skill_index('{"$schema": "test", "skills": []}')
assert index.skills == []
def test_parses_missing_skills_key(self) -> None:
index = _parse_mcp_skill_index('{"$schema": "test"}')
assert index.skills == []
def test_raises_on_non_object(self) -> None:
with pytest.raises(ValueError, match="must be a JSON object"):
_parse_mcp_skill_index("[]")
def test_raises_on_invalid_json(self) -> None:
with pytest.raises(json.JSONDecodeError):
_parse_mcp_skill_index("not json")
def test_skips_non_dict_entries(self) -> None:
index = _parse_mcp_skill_index('{"skills": ["not-a-dict", {"name": "ok", "type": "skill-md"}]}')
assert len(index.skills) == 1
assert index.skills[0].name == "ok"
# ---------------------------------------------------------------------------
# MCPSkillResource tests
# ---------------------------------------------------------------------------
class TestMCPSkillResource:
"""Tests for MCPSkillResource."""
@pytest.mark.asyncio
async def test_read_text_content(self) -> None:
result = _make_text_result("hello world")
resource = MCPSkillResource(name="test.md", result=result)
content = await resource.read()
assert content == "hello world"
@pytest.mark.asyncio
async def test_read_binary_content(self) -> None:
data = bytes([0x01, 0x02, 0x03, 0x04])
result = _make_blob_result(data)
resource = MCPSkillResource(name="icon.bin", result=result)
content = await resource.read()
assert content == data
@pytest.mark.asyncio
async def test_read_empty_returns_none(self) -> None:
result = _make_empty_result()
resource = MCPSkillResource(name="empty", result=result)
content = await resource.read()
assert content is None
@pytest.mark.asyncio
async def test_read_multiple_text_contents_joined(self) -> None:
result = ReadResourceResult(
contents=[
TextResourceContents(uri=AnyUrl("skill://a"), text="line1", mimeType="text/plain"),
TextResourceContents(uri=AnyUrl("skill://b"), text="line2", mimeType="text/plain"),
]
)
resource = MCPSkillResource(name="multi", result=result)
content = await resource.read()
assert content == "line1\nline2"
@pytest.mark.asyncio
async def test_binary_takes_precedence_over_text(self) -> None:
data = b"\xff\xfe"
result = ReadResourceResult(
contents=[
TextResourceContents(uri=AnyUrl("skill://a"), text="text", mimeType="text/plain"),
BlobResourceContents(
uri=AnyUrl("skill://b"),
blob=base64.b64encode(data).decode(),
mimeType="application/octet-stream",
),
]
)
resource = MCPSkillResource(name="mixed", result=result)
content = await resource.read()
# The implementation iterates all contents checking for BlobResourceContents
# first, so when both text and binary are present, binary is returned.
assert content == data
# ---------------------------------------------------------------------------
# MCPSkill tests
# ---------------------------------------------------------------------------
class TestMCPSkill:
"""Tests for MCPSkill."""
@pytest.mark.asyncio
async def test_get_content_fetches_and_caches(self) -> None:
client = _make_client(**{"skill://unit-converter/SKILL.md": _make_text_result(SAMPLE_SKILL_MD)})
from agent_framework import SkillFrontmatter
fm = SkillFrontmatter(name="unit-converter", description="Convert between common units.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://unit-converter/SKILL.md", client=client)
content1 = await skill.get_content()
content2 = await skill.get_content()
assert "Body content here." in content1
assert content1 == content2
# Only one MCP call should be made (cached)
assert client.read_resource.call_count == 1
@pytest.mark.asyncio
async def test_get_content_raises_on_empty(self) -> None:
client = _make_client(**{"skill://empty/SKILL.md": _make_empty_result()})
from agent_framework import SkillFrontmatter
fm = SkillFrontmatter(name="empty-skill", description="Empty skill.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://empty/SKILL.md", client=client)
with pytest.raises(ValueError, match="no text content"):
await skill.get_content()
@pytest.mark.asyncio
async def test_get_resource_text(self) -> None:
client = _make_client(
**{
"skill://unit-converter/SKILL.md": _make_text_result(SAMPLE_SKILL_MD),
"skill://unit-converter/references/checklist.md": _make_text_result("- check thing 1\n- check thing 2"),
}
)
from agent_framework import SkillFrontmatter
fm = SkillFrontmatter(name="unit-converter", description="Convert between common units.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://unit-converter/SKILL.md", client=client)
resource = await skill.get_resource("references/checklist.md")
assert resource is not None
content = await resource.read()
assert content == "- check thing 1\n- check thing 2"
@pytest.mark.asyncio
async def test_get_resource_binary(self) -> None:
data = bytes([0x01, 0x02, 0x03, 0x04])
client = _make_client(
**{
"skill://unit-converter/SKILL.md": _make_text_result(SAMPLE_SKILL_MD),
"skill://unit-converter/assets/icon.bin": _make_blob_result(data),
}
)
from agent_framework import SkillFrontmatter
fm = SkillFrontmatter(name="unit-converter", description="Convert between common units.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://unit-converter/SKILL.md", client=client)
resource = await skill.get_resource("assets/icon.bin")
assert resource is not None
content = await resource.read()
assert content == data
@pytest.mark.asyncio
async def test_get_resource_unknown_returns_none(self) -> None:
client = _make_client(**{"skill://unit-converter/SKILL.md": _make_text_result(SAMPLE_SKILL_MD)})
from agent_framework import SkillFrontmatter
fm = SkillFrontmatter(name="unit-converter", description="Convert between common units.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://unit-converter/SKILL.md", client=client)
resource = await skill.get_resource("references/does-not-exist.md")
assert resource is None
@pytest.mark.asyncio
@pytest.mark.parametrize(
"name",
[
"../escape.md",
"references/../../escape.md",
"..",
"..\\escape.md",
"/etc/passwd",
"http://attacker.example.com/payload",
],
)
async def test_get_resource_path_traversal_returns_none(self, name: str) -> None:
# Register a permissive mock that would happily return content for any URI,
# so the test fails unless the client-side validation rejects the name
# before issuing the read.
client = AsyncMock()
client.read_resource = AsyncMock(return_value=_make_text_result("should never be returned"))
from agent_framework import SkillFrontmatter
fm = SkillFrontmatter(name="unit-converter", description="Convert between common units.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://unit-converter/SKILL.md", client=client)
resource = await skill.get_resource(name)
assert resource is None
client.read_resource.assert_not_called()
@pytest.mark.asyncio
async def test_get_resource_empty_name_returns_none(self) -> None:
client = _make_client()
from agent_framework import SkillFrontmatter
fm = SkillFrontmatter(name="test-skill", description="Test.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://test/SKILL.md", client=client)
assert await skill.get_resource("") is None
assert await skill.get_resource(" ") is None
@pytest.mark.asyncio
async def test_get_script_returns_none(self) -> None:
client = _make_client()
from agent_framework import SkillFrontmatter
fm = SkillFrontmatter(name="test-skill", description="Test.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://test/SKILL.md", client=client)
assert await skill.get_script("anything") is None
def test_compute_skill_root_uri_strips_suffix(self) -> None:
assert MCPSkill._compute_skill_root_uri("skill://unit-converter/SKILL.md") == "skill://unit-converter/"
def test_compute_skill_root_uri_trailing_slash(self) -> None:
assert MCPSkill._compute_skill_root_uri("skill://unit-converter/") == "skill://unit-converter/"
def test_compute_skill_root_uri_no_suffix_adds_slash(self) -> None:
assert MCPSkill._compute_skill_root_uri("skill://unit-converter") == "skill://unit-converter/"
# ---------------------------------------------------------------------------
# MCPSkillsSource tests
# ---------------------------------------------------------------------------
class TestMCPSkillsSource:
"""Tests for MCPSkillsSource."""
@pytest.mark.asyncio
async def test_index_based_discovery_returns_skill(self) -> None:
client = _make_client(
**{
"skill://index.json": _make_text_result(SAMPLE_SKILL_INDEX, uri="skill://index.json"),
"skill://unit-converter/SKILL.md": _make_text_result(SAMPLE_SKILL_MD),
}
)
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert len(skills) == 1
assert skills[0].frontmatter.name == "unit-converter"
assert skills[0].frontmatter.description == "Convert between common units."
# Content is fetched on demand, not during discovery
content = await skills[0].get_content()
assert "Body content here." in content
@pytest.mark.asyncio
async def test_no_index_returns_empty(self) -> None:
client = _make_client() # No resources at all
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert skills == []
@pytest.mark.asyncio
async def test_does_not_read_skill_md_during_discovery(self) -> None:
# Index points to a skill, but SKILL.md is not registered on the server.
# Discovery should succeed because it only reads the index.
client = _make_client(
**{"skill://index.json": _make_text_result(SAMPLE_SKILL_INDEX, uri="skill://index.json")}
)
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert len(skills) == 1
assert skills[0].frontmatter.name == "unit-converter"
@pytest.mark.asyncio
async def test_invalid_name_is_skipped(self) -> None:
index_json = json.dumps(
{
"$schema": "https://schemas.agentskills.io/discovery/0.2.0/schema.json",
"skills": [
{
"name": "UnitConverter", # Invalid: uppercase
"type": "skill-md",
"description": "Convert between common units.",
"url": "skill://UnitConverter/SKILL.md",
}
],
}
)
client = _make_client(**{"skill://index.json": _make_text_result(index_json, uri="skill://index.json")})
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert skills == []
@pytest.mark.asyncio
async def test_missing_required_fields_is_skipped(self) -> None:
index_json = json.dumps(
{
"$schema": "https://schemas.agentskills.io/discovery/0.2.0/schema.json",
"skills": [
{
"name": "unit-converter",
"type": "skill-md",
# Missing description and url
}
],
}
)
client = _make_client(**{"skill://index.json": _make_text_result(index_json, uri="skill://index.json")})
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert skills == []
@pytest.mark.asyncio
async def test_unsupported_type_is_skipped(self) -> None:
index_json = json.dumps(
{
"$schema": "https://schemas.agentskills.io/discovery/0.2.0/schema.json",
"skills": [
{
"name": "some-skill",
"type": "archive",
"description": "Packaged skill.",
"url": "skill://some-skill.tar.gz",
}
],
}
)
client = _make_client(**{"skill://index.json": _make_text_result(index_json, uri="skill://index.json")})
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert skills == []
@pytest.mark.asyncio
async def test_template_type_is_skipped(self) -> None:
index_json = json.dumps(
{
"$schema": "https://schemas.agentskills.io/discovery/0.2.0/schema.json",
"skills": [
{
"type": "mcp-resource-template",
"description": "Per-product documentation skill",
"url": "skill://docs/{product}/SKILL.md",
}
],
}
)
client = _make_client(**{"skill://index.json": _make_text_result(index_json, uri="skill://index.json")})
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert skills == []
@pytest.mark.asyncio
async def test_empty_index_returns_empty(self) -> None:
client = _make_client(
**{"skill://index.json": _make_text_result('{"skills": []}', uri="skill://index.json")}
)
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert skills == []
@pytest.mark.asyncio
async def test_malformed_index_json_returns_empty(self) -> None:
client = _make_client(
**{"skill://index.json": _make_text_result("not valid json", uri="skill://index.json")}
)
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert skills == []
@pytest.mark.asyncio
async def test_sibling_text_resource(self) -> None:
client = _make_client(
**{
"skill://index.json": _make_text_result(SAMPLE_SKILL_INDEX, uri="skill://index.json"),
"skill://unit-converter/SKILL.md": _make_text_result(SAMPLE_SKILL_MD),
"skill://unit-converter/references/checklist.md": _make_text_result("- check thing 1\n- check thing 2"),
}
)
source = MCPSkillsSource(client=client)
skill = (await source.get_skills())[0]
resource = await skill.get_resource("references/checklist.md")
assert resource is not None
content = await resource.read()
assert content == "- check thing 1\n- check thing 2"
@pytest.mark.asyncio
async def test_sibling_binary_resource(self) -> None:
data = bytes([0x01, 0x02, 0x03, 0x04])
client = _make_client(
**{
"skill://index.json": _make_text_result(SAMPLE_SKILL_INDEX, uri="skill://index.json"),
"skill://unit-converter/SKILL.md": _make_text_result(SAMPLE_SKILL_MD),
"skill://unit-converter/assets/icon.bin": _make_blob_result(data),
}
)
source = MCPSkillsSource(client=client)
skill = (await source.get_skills())[0]
resource = await skill.get_resource("assets/icon.bin")
assert resource is not None
content = await resource.read()
assert content == data
# ---------------------------------------------------------------------------
# McpError code branching tests
# ---------------------------------------------------------------------------
class TestMCPSkillsSourceErrorCodeBranching:
"""Tests that MCPSkillsSource and MCPSkill branch on McpError.error.code.
Only "not found" codes (RESOURCE_NOT_FOUND -32002, METHOD_NOT_FOUND -32601)
should be silently swallowed as "no skills available." Other McpError codes
and non-McpError exceptions must propagate so that auth failures, server
crashes, and connection drops are visible.
"""
@pytest.mark.asyncio
async def test_index_method_not_found_returns_empty(self) -> None:
"""METHOD_NOT_FOUND (-32601) -> server doesn't support resources/read."""
client = AsyncMock()
client.read_resource = AsyncMock(side_effect=McpError(error=ErrorData(code=-32601, message="Method not found")))
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert skills == []
@pytest.mark.asyncio
async def test_index_resource_not_found_returns_empty(self) -> None:
"""MCP-spec "Resource not found" (-32002) -> server has no index."""
client = AsyncMock()
client.read_resource = AsyncMock(
side_effect=McpError(error=ErrorData(code=-32002, message="Resource not found"))
)
source = MCPSkillsSource(client=client)
skills = await source.get_skills()
assert skills == []
@pytest.mark.asyncio
async def test_index_invalid_params_propagates(self) -> None:
"""INVALID_PARAMS (-32602) is a real bug, must propagate (not "not found")."""
client = AsyncMock()
client.read_resource = AsyncMock(side_effect=McpError(error=ErrorData(code=-32602, message="Invalid params")))
source = MCPSkillsSource(client=client)
with pytest.raises(McpError):
await source.get_skills()
@pytest.mark.asyncio
async def test_index_internal_error_propagates(self) -> None:
"""INTERNAL_ERROR (-32603) must propagate, not silently return empty."""
client = AsyncMock()
client.read_resource = AsyncMock(side_effect=McpError(error=ErrorData(code=-32603, message="Internal error")))
source = MCPSkillsSource(client=client)
with pytest.raises(McpError):
await source.get_skills()
@pytest.mark.asyncio
async def test_index_connection_closed_propagates(self) -> None:
"""CONNECTION_CLOSED (-32000) must propagate."""
client = AsyncMock()
client.read_resource = AsyncMock(
side_effect=McpError(error=ErrorData(code=-32000, message="Connection closed"))
)
source = MCPSkillsSource(client=client)
with pytest.raises(McpError):
await source.get_skills()
@pytest.mark.asyncio
async def test_index_generic_error_code_propagates(self) -> None:
"""Generic handler error (code 0) must propagate."""
client = AsyncMock()
client.read_resource = AsyncMock(side_effect=McpError(error=ErrorData(code=0, message="Some handler error")))
source = MCPSkillsSource(client=client)
with pytest.raises(McpError):
await source.get_skills()
@pytest.mark.asyncio
async def test_index_non_mcp_error_propagates(self) -> None:
"""Non-McpError exceptions (connection drop, timeout) must propagate."""
client = AsyncMock()
client.read_resource = AsyncMock(side_effect=ConnectionError("connection lost"))
source = MCPSkillsSource(client=client)
with pytest.raises(ConnectionError):
await source.get_skills()
@pytest.mark.asyncio
async def test_get_resource_internal_error_propagates(self) -> None:
"""McpError with INTERNAL_ERROR on get_resource must propagate."""
from agent_framework import SkillFrontmatter
client = AsyncMock()
client.read_resource = AsyncMock(side_effect=McpError(error=ErrorData(code=-32603, message="Server crashed")))
fm = SkillFrontmatter(name="test-skill", description="Test.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://test/SKILL.md", client=client)
with pytest.raises(McpError):
await skill.get_resource("references/file.md")
@pytest.mark.asyncio
async def test_get_resource_not_found_returns_none(self) -> None:
"""McpError with RESOURCE_NOT_FOUND (-32002) on get_resource returns None."""
from agent_framework import SkillFrontmatter
client = AsyncMock()
client.read_resource = AsyncMock(
side_effect=McpError(error=ErrorData(code=-32002, message="Resource not found"))
)
fm = SkillFrontmatter(name="test-skill", description="Test.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://test/SKILL.md", client=client)
result = await skill.get_resource("references/file.md")
assert result is None
@pytest.mark.asyncio
async def test_get_resource_connection_error_propagates(self) -> None:
"""A plain ConnectionError on get_resource must propagate, not return None."""
from agent_framework import SkillFrontmatter
client = AsyncMock()
client.read_resource = AsyncMock(side_effect=ConnectionError("connection lost"))
fm = SkillFrontmatter(name="test-skill", description="Test.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://test/SKILL.md", client=client)
with pytest.raises(ConnectionError):
await skill.get_resource("references/file.md")
@pytest.mark.asyncio
async def test_get_resource_timeout_error_propagates(self) -> None:
"""A TimeoutError on get_resource must propagate, not return None."""
from agent_framework import SkillFrontmatter
client = AsyncMock()
client.read_resource = AsyncMock(side_effect=TimeoutError("read timed out"))
fm = SkillFrontmatter(name="test-skill", description="Test.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://test/SKILL.md", client=client)
with pytest.raises(TimeoutError):
await skill.get_resource("references/file.md")
@pytest.mark.asyncio
async def test_get_resource_generic_mcp_error_propagates(self) -> None:
"""McpError with a generic code (0) on get_resource must propagate."""
from agent_framework import SkillFrontmatter
client = AsyncMock()
client.read_resource = AsyncMock(
side_effect=McpError(error=ErrorData(code=0, message="Handler error"))
)
fm = SkillFrontmatter(name="test-skill", description="Test.")
skill = MCPSkill(frontmatter=fm, skill_md_uri="skill://test/SKILL.md", client=client)
with pytest.raises(McpError):
await skill.get_resource("references/file.md")
@pytest.mark.asyncio
async def test_index_timeout_error_propagates(self) -> None:
"""A TimeoutError reading skill://index.json must propagate."""
client = AsyncMock()
client.read_resource = AsyncMock(side_effect=TimeoutError("read timed out"))
source = MCPSkillsSource(client=client)
with pytest.raises(TimeoutError):
await source.get_skills()