guardrail_check

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the transparency burden; it discloses that the tool returns ALLOW, WARN, or BLOCK with a concrete explanation and implies it does not execute the proposed action. It could add explicit no-side-effect or error behavior, but for a guardrail check the core behavior is clearly conveyed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences: the first front-loads the purpose and output, the second gives a concrete usage rule. No words are wasted, and the structure makes the call conventions immediately findable.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the essential aspects an agent needs: what it evaluates, when to call it, and the expected return values. Since there is no output schema, the explicit mention of ALLOW/WARN/BLOCK with explanations fills that gap well, making the description sufficient for this moderately complex tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already describes all three parameters, and schema coverage is 100%, so the description adds little beyond labeling the call as 'proposed'. This matches the baseline of 3 for fully schema-documented parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb-resource pair: 'Evaluate a proposed tool call against the Guardrail policy', which clearly identifies the action and subject. It also distinguishes the tool from siblings by emphasizing 'BEFORE executing it' and enumerating the return values (ALLOW, WARN, or BLOCK), making its role distinct from guardrail_record_outcome and guardrail_agent_history.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly says 'Always call this before performing any action that spends money, deletes data, sends messages externally, or runs code', which is strong when-to-use guidance. It does not name sibling alternatives or state when not to use it, but the 'before' framing implicitly separates it from outcome recording.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.