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

The description discloses important behaviors beyond the annotations: it replaces the entire selection, anything omitted is turned off, and the action rebuilds/republishes the script with a CDN propagation delay. This is exactly the kind of contextual behavioral information an agent needs and is not present in idempotentHint or destructiveHint.

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?

Three sentences, each earning its place: the core purpose, the critical replacement caveat, and the prerequisite plus propagation effect. The information is front-loaded and free of filler.

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?

Given only two parameters, full schema coverage, and no output schema, the description covers all essential context: what is changed, how the selection should be provided, how to get valid values, and when the change takes effect for visitors. Nothing important is missing.

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 100%, so the schema already documents both parameters. The description reinforces the 'complete list, not a delta' semantics for features and adds the pragmatic reminder to fetch valid ids first, but it mostly restates what the schema already conveys.

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 and resource: 'Set which tracking features the site's script includes.' This clearly identifies the tool's job and distinguishes it from get_tracking_settings and get_tracking_snippet. The replacement caveat further sharpens the 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?

The description gives an explicit prerequisite ('Call get_tracking_settings first for the valid ids') and explains the correct calling pattern by saying the caller must send the complete feature list. It does not explicitly name alternatives or when not to use this tool, but the purpose and precondition make its use context clear.

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