compare_instances

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is known. The description adds useful context about optional query scoping and the ability to compare either record counts or property values. However, it does not disclose prerequisites like what 'configured' instances entail or what happens when both optional parameters are omitted.

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 tight and front-loaded: two sentences that immediately state the action and purpose. There is no fluff, and every word contributes to understanding.

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 tool has 5 parameters and no output schema, so the description needs to cover the main use cases. It does that, but it lacks a description of the return format or behavior when neither table nor property is specified. The mention of 'configured' instances is also vague, leaving a small but meaningful gap in completeness.

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 has 100% description coverage, so parameters are already documented. The description adds a bit of context by mapping 'table', 'query', and 'property' to the comparison types, but this is redundant with the schema descriptions and does not provide significant additional meaning.

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 uses a specific verb 'Compare' and a clear resource 'two configured ServiceNow instances', and explicitly states what is compared (record counts and/or system property values). This distinguishes it from sibling tools like compare_record_counts or get_system_property, which operate on a single instance or a different scope.

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 provides a clear use case ('dev→prod drift detection and governance') and implies cross-instance comparison, which differentiates it from sibling tools. However, it does not explicitly state when not to use it or mention alternatives, though the context is clear enough for an agent.

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