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FabledGrimoire/tests/test_mcp_strict_args.py
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bvandeusenandClaude Opus 5.5 914f31359c
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docs(6209): the remaining test files — lessons, reply moment and shape, retrieval specs and scopes, rule doors and judgments, services, snippets, search scope; five tests renamed to their property
Docstrings, section headers and assertion messages drop the record number,
milestone or step that introduced the behaviour, and incident accounts are
restated as the present-tense failure shape. A dead pointer to a design doc
that is not in the repo is removed.

Renamed to the property they check:
  test_the_old_shape_would_be_caught -> test_a_rank_then_scope_query_is_caught
  test_a_ledger_repeat_no_longer_produces_that_case_at_all -> test_a_ledger_repeat_is_counted_not_withheld
  test_the_header_no_longer_promises_once_per_session -> test_the_header_explains_the_seen_marker
  test_the_portal_case_no_longer_stamps_one_canon_onto_a_whole_file -> test_one_canon_is_not_stamped_onto_a_whole_file
  test_the_repos_own_prose_no_longer_defines_with -> test_the_repos_own_prose_does_not_define_with
  test_the_original_regression_create_note_with_content -> test_the_real_server_refuses_content_on_create_note

Fixture and example ids stay: "note 5" in a supersession chain, "rule 156"
in an illustrative question, `#2275` as the hex-versus-citation case,
`#3244` as the example of a bare number, fixed dates in date-filter tests.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-21 21:44:58 -04:00

128 lines
4.6 KiB
Python

"""Unknown tool arguments are rejected, never silently dropped.
The failure this pins: MCPServer validates tool arguments with a pydantic model
whose extra-field policy is "ignore", so `create_note(content=...)` — a
plausible near-miss for `body=`, primed by add_task_log's `content` — would
run, store `body: ""`, and leave a record embedding/search cannot see, while
REPORTING SUCCESS.
The rejection is at the dispatch seam, not per-tool: StrictArgsMCPServer rejects any
call carrying arguments the tool does not declare, with a did-you-mean when
one is close. An error the caller sees once beats data half-written forever.
"""
import pytest
from mcp.server.mcpserver.exceptions import ToolError, UnexpectedToolError
from scribe.mcp.server import StrictArgsMCPServer
def _echo_server() -> StrictArgsMCPServer:
mcp = StrictArgsMCPServer("strict-test")
@mcp.tool()
def echo(text: str = "") -> str:
return text
return mcp
async def test_declared_arguments_still_dispatch():
mcp = _echo_server()
result = await mcp.call_tool("echo", {"text": "hi"})
assert "hi" in str(result)
async def test_unknown_argument_is_an_error_not_a_silent_drop():
"""The load-bearing property: the call must FAIL, because succeeding is
what turned a typo into data loss."""
mcp = _echo_server()
with pytest.raises(ToolError) as exc:
await mcp.call_tool("echo", {"txt": "hi"})
msg = str(exc.value)
assert "'txt'" in msg
assert "did you mean 'text'?" in msg # difflib near-miss hint
assert "Nothing was created or changed" in msg
async def test_empty_arguments_pass():
mcp = _echo_server()
assert await mcp.call_tool("echo", {}) is not None
async def test_unknown_tool_keeps_the_upstream_error():
"""The gate must not swallow or reshape 'no such tool' — that error path
belongs to MCPServer and clients already understand it."""
mcp = _echo_server()
with pytest.raises(Exception) as exc:
await mcp.call_tool("no_such_tool", {"text": "hi"})
assert "no_such_tool" in str(exc.value)
# --- a refusal's text reaches the agent ---------------------------------------
#
# SDK 2.x passes on only a ToolError's text; anything else is wrapped as
# "Error executing tool X" and its message is kept on the server. ValueError is
# how every Scribe tool refuses, so without this every refusal arrives bare.
def _raising_server() -> StrictArgsMCPServer:
mcp = StrictArgsMCPServer("refusal-test")
@mcp.tool()
def refuse() -> str:
raise ValueError("record 7 is not yours to change — open your own copy")
@mcp.tool()
def crash() -> str:
raise RuntimeError("password=hunter2 at db.internal:5432")
return mcp
async def test_a_refusal_reaches_the_caller_with_its_reason():
mcp = _raising_server()
with pytest.raises(ToolError) as exc:
await mcp.call_tool("refuse", {})
msg = str(exc.value)
assert "Error executing tool refuse" in msg
assert "record 7 is not yours to change — open your own copy" in msg
assert not isinstance(exc.value, UnexpectedToolError), (
"still typed as a crash, so the SDK's handler would log it as one")
async def test_a_crash_stays_masked():
"""Only the refusal convention is unmasked: a crash's text can carry
internals, and the SDK hides it for that reason."""
mcp = _raising_server()
with pytest.raises(UnexpectedToolError) as exc:
await mcp.call_tool("crash", {})
assert "hunter2" not in str(exc.value)
@pytest.mark.usefixtures("_bind_user")
async def test_a_real_tools_refusal_reaches_the_caller():
"""Against the real server, on a refusal that needs no database: the
message judge_menu writes for an empty verdict list."""
from scribe.mcp.server import build_mcp_server
with pytest.raises(ToolError) as exc:
await build_mcp_server().call_tool("judge_menu", {"log_id": 1, "verdicts": []})
assert "at least one verdict" in str(exc.value)
async def test_the_real_server_refuses_content_on_create_note():
"""Against the REAL server: `content=` on create_note
must raise before dispatch — naming the bad argument and listing `body`
among the accepted ones — instead of creating a body-less note."""
from scribe.mcp.server import build_mcp_server
mcp = build_mcp_server()
assert isinstance(mcp, StrictArgsMCPServer) # the guard is actually mounted
with pytest.raises(ToolError) as exc:
await mcp.call_tool(
"create_note", {"title": "t", "content": "the body text"}
)
msg = str(exc.value)
assert "'content'" in msg
assert "body" in msg