explain_preflight_rule

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered by structured data. The description's 'READ-ONLY' prefix reinforces but does not add to this. It adds minimal behavioral context beyond confirming the rule-explanation output, and does not contradict the annotations.

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?

A single, front-loaded sentence with zero waste. The 'READ-ONLY' prefix overlaps with annotations but is harmless. Appropriately sized for a simple single-parameter tool.

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?

For a low-complexity tool (1 parameter, no output schema, no nesting), the description is reasonably complete — it states what the returned explanation covers. It partially compensates for the missing output schema by describing the explanation's contents, though it doesn't address error behavior for an invalid rule_id. Adequate given the tool's simplicity.

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 coverage is 100% — rule_id is documented with an example ('campaign.daily_volume'). The description adds no parameter-level meaning beyond implying that rule_id selects the rule to explain, which the schema already conveys. Baseline 3 is appropriate since the schema carries the parameter burden.

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 states a specific verb ('Explain') and resource ('one rule'), and clarifies what the explanation covers (checks, data needs, configurable options). It implicitly distinguishes from siblings like list_preflight_rules and validate_preflight_config, though it does not name them explicitly. A clear, well-scoped purpose.

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?

No guidance is given on when to use this tool versus its siblings. The description does not state that this should be used when detailed information about a single rule is needed as opposed to list_preflight_rules for enumeration or validate_preflight_config for config checking. No exclusions or alternative routing provided.

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