FA-99741 / Tool call schema validation / Open access

Required property presence is confused with truthiness · case 01

Required property presence is confused with truthiness.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The validator treats a present falsey value as absent.

THE FAILURE

The validator treats a present falsey value as absent.

Unsuccessful approach: Rejecting null values still rejects a present property when null is a valid value.

Case contract

A mapping is valid when every required key exists, even if its value is null, false, zero, or empty.

Why this case matters

Tool argument validation prevents malformed structured payloads from entering a deterministic downstream operation.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(obj, required):
    return all(obj.get(k) for k in required)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('false value present',solve({'enabled':False},['enabled']),True)
check('zero present',solve({'count':0},['count']),True)
check('null present',solve({'x':None},['x']),True)
check('missing key',solve({'x':1},['y']),False)
check('empty requirements',solve({},[]),True)
check('mixed keys',solve({'a':0,'b':''},['a','b']),True)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
false value present	`False`	`True`	Failed
zero present	`False`	`True`	Failed
null present	`False`	`True`	Failed
missing key	`False`	`False`	Passed
empty requirements	`True`	`True`	Passed
mixed keys	`False`	`True`	Failed

SHA-256 / 2b7cad37f6abb7505fa839e786c15e0633c5f6f6dccf8ee20b6542a7b3f5ba2b

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(obj, required):
    return all(k in obj and obj[k] is not None for k in required)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('false value present',solve({'enabled':False},['enabled']),True)
check('zero present',solve({'count':0},['count']),True)
check('null present',solve({'x':None},['x']),True)
check('missing key',solve({'x':1},['y']),False)
check('empty requirements',solve({},[]),True)
check('mixed keys',solve({'a':0,'b':''},['a','b']),True)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
false value present	`True`	`True`	Passed
zero present	`True`	`True`	Passed
null present	`False`	`True`	Failed
missing key	`False`	`False`	Passed
empty requirements	`True`	`True`	Passed
mixed keys	`True`	`True`	Passed

SHA-256 / a639604ea3df29442f9475f6034404cafb61d84016ede9255b140dcfb4e8871f

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 6 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Verification & scope

Self-contained toy JSON-like schema contract over in-memory Python values; no compatibility with a production schema standard or callable binding is claimed. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-30T16:48:27.615698+00:00.

Case digest / 1cf9934f8ad541a4659bb410f7ef06df47412ca2500a839d11f83032ce5396cc