AI Agent Guardrails: Input, Tool and Output Authorization Boundaries

List data, tools and permitted actions

Define users, resources, operations and consequential outcomes. Deny unapproved access/actions by default, then identify the enforcing component and tests. Read-only access can cause serious disclosure; it still needs identity/resource scope.

Input, tool and output layers organize controls rather than exhaust threats or define an SDK architecture. Prompts may help constrain behavior, but permissions, limits and approval cannot rely only on model judgment.

Input: separate untrusted content from authority

User messages, retrieved documents, tool results and images can carry untrusted instructions. OWASP LLM01:2025 describes direct/indirect injection and varied forms. Phrase checks or another model may mitigate risks without blocking every attack.

Limit source/task scope and test encoded, cross-source and tool-result instructions. Supply necessary, appropriately authorized data. If masking/token replacement is used, check tools, logs, caches, outputs and protected replacement mappings. Data possession does not authorize reuse; establish purpose/necessity under the Taiwan PDPA.

Tools: authorize the actual request downstream

Tool services check current identity, resource, action, parameters, units, limits and approval. A model-selected tool name cannot grant access to a resource. Bind consequential approval to the request, including checks for parameter changes afterward.

These fields are pseudoconfiguration for planning, not an executable SDK format. Implementations need enforcing components and rule precedence.

Refund/email tools are outside the example allowlist. Confirmation entries do not authorize them. OWASP LLM06:2025 emphasizes least functionality/privilege, user context and downstream authorization. Rate limits reduce damage; one unauthorized or duplicate action can still matter.

Output: validate content and action state separately

Schemas check structure/fields. Citation checks must assess claim support, versions and applicability. Correct format, tone or source existence alone does not establish factual/regulatory correctness.

Generation retries need declared count/cost budgets. Payment, email or mutation retries depend on the external service's deduplication/acknowledgement contract. Timeout or missing acknowledgement does not prove nothing happened. Stop, reconcile state or refer to the owner rather than resending blindly. Output blocking cannot undo earlier side effects.

Test negative paths

For the actual task, test:

• Denied users, wrong resources/tools and post-approval parameter changes.
• Excess limits, inconsistent units, duplicates and unknown outcomes.
• Untrusted documents/tools requesting expanded authority.
• Masked data appearing through other output/log paths.
• Failed checks, unsupported simulation and dependency outages.

Retain necessary identity, request, approval, version and refusal records without raw secrets. Assign handover, stop, reconciliation and recovery conditions; recheck affected behavior after changes. NIST AI RMF (January 26, 2023) provides voluntary risk/monitoring guidance, not security certification.

Sources reviewed October 4, 2026. OWASP's 2025 denotes document versions; exact publication/update dates were not established. See agent sandbox boundaries or define permitted tasks/interfaces through the Agentic workflow service.