compare_prompts

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

Annotations already cover readOnly, idempotent, non-destructive, closed-world. The description adds a meaningful behavioral trait beyond them: output is descriptive trade-off analysis rather than a ranked winner. With annotations carrying the safety profile, this extra contextual disclosure earns a 4.

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?

Two terse sentences, front-loaded with the verb+resource and immediately followed by the differentiator. Zero waste.

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?

Output schema exists, so return values need not be explained. Annotations cover safety. The remaining gap is that, with 0% parameter descriptions, the agent must guess parameter semantics; the description's phrase 'task context' helps but does not fully close it. Still complete enough for a comparison 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?

Schema description coverage is 0%, so the schema names promptA/promptB/taskContext but explains nothing. The description compensates partially by implying the two prompts and 'task context' are what get compared, but it never states syntax, limits, or whether taskContext is optional-in-practice. Baseline 3 given partial compensation for a 0%-coverage gap.

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?

Specific verb 'compare' plus resource 'two instructions' and the mechanism 'by heuristic dimensions and task context'. The negation 'does not declare an arbitrary winner' distinguishes it from sibling evaluate_prompt, which presumably ranks or scores.

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?

Contains one useful boundary marker: it produces comparisons, not verdicts. However, it never says when to reach for this versus evaluate_prompt, optimize_prompt, or inspect_prompt, so the agent must infer the selection context.

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