FA-99791 / Tool call schema validation / Open access

Duplicate array values pass a uniqueness constraint · case 01

Duplicate array values pass a uniqueness constraint.

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

ROOT CAUSE

Each value is tested for membership in the same list, a tautology that never detects repetition.

THE FAILURE

Each value is tested for membership in the same list, a tautology that never detects repetition.

Unsuccessful approach: A set catches common duplicates but treats true and one as the same value.

Case contract

Array uniqueness uses JSON-like type-sensitive scalar identity; an empty or singleton list is unique.

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(values):
    return all(v in values for v in values)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('distinct values',solve([N,N+1]),True)
check('duplicate string',solve(['x','x']),False)
check('bool and integer distinct',solve([True,1]),True)
check('empty',solve([]),True)
check('singleton',solve([False]),True)
check('repeated null',solve([None,None]),False)
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
distinct values	`True`	`True`	Passed
duplicate string	`True`	`False`	Failed
bool and integer distinct	`True`	`True`	Passed
empty	`True`	`True`	Passed
singleton	`True`	`True`	Passed
repeated null	`True`	`False`	Failed

SHA-256 / 8c15fbde4375eb252d6c35e64d3d24234ea0252dd60316e25989e48c703cfa17

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(values):
    return len(set(values))==len(values)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('distinct values',solve([N,N+1]),True)
check('duplicate string',solve(['x','x']),False)
check('bool and integer distinct',solve([True,1]),True)
check('empty',solve([]),True)
check('singleton',solve([False]),True)
check('repeated null',solve([None,None]),False)
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
distinct values	`True`	`True`	Passed
duplicate string	`False`	`False`	Passed
bool and integer distinct	`False`	`True`	Failed
empty	`True`	`True`	Passed
singleton	`True`	`True`	Passed
repeated null	`False`	`False`	Passed

SHA-256 / 3fa63fc90cacd411619f9ade93bc90ad544ac63cb3c699c0f6d363c3a9404b84

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 2026-09-30T16:48:28.064411+00:00.

Case digest / 71f6f60039407d9cdde1a7f64fc6a6a3677d69ee2424c5fa6ac08416f84bb943