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

Annotations already declare write/destructive/idempotent behavior, but the description adds substantial value: the watch-package prerequisite, the 409 response with `limit` and `plans`, report scheduling (first immediate, then weekly), and optimistic-concurrency ('Saves use the expected version'). It stops short of explaining what toggling off does to existing competitors.

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?

Front-loaded and reasonably sized, but the watch-package prerequisite is stated twice ('Turning on needs a watch package in force. Turning on needs a watch package in force and a free site in it...'), which is redundant and wastes a sentence.

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 mutating, concurrency-sensitive tool with no output schema, the description covers prerequisites, an error case, report timing, and version semantics adequately. Minor gaps remain on the effect of turning reports off, but the core call requirements are present.

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%, so the schema already documents all four parameters, establishing the baseline of 3. The description's 'set up to 3 competitors' and 'Saves use the expected version' lightly reinforce but do not deepen the schema's own descriptions.

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?

States a specific verb and resource ('Turn the weekly report of a site on or off and set up to 3 competitors') with clear scope. It does not, however, distinguish itself from sibling tools like weekly_site_report or weekly_site_report_history, leaving the agent to infer this is the save/mutation variant.

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?

It gives a prerequisite ('needs a watch package in force') which is useful context, but offers no explicit when-to-use guidance or references to alternatives among the weekly_site_report* siblings. Usage is only implied.

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