evaluator: output schema injection

[achuvyas-kv]

Area

Agent Evaluators (evaluators/agent/)

Problem or motivation

When agents output structured JSON, attackers can attempt to inject additional fields or override expected schema fields, potentially affecting downstream consumers.

Proposed solution

Add evaluator under evaluators/agent/injection/ that:

• Tests if malicious input can inject fields into structured output
• Covers JSON/XML output manipulation attempts

Acceptance criteria

• Evaluator YAML file created with pass/fail criteria
• Patterns cover field injection and schema manipulation
• Maps to relevant injection standards

Alternatives considered

No response