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

Annotations already declare destructiveHint=true, idempotentHint=true and openWorldHint=true, so the mutation profile is covered. The description adds genuinely new context beyond annotations: the lookup behavior for location strings, the domain-based default country rule (.in, .com.au, .co.uk), and the requirement that .com/.io brands set one before ranking runs. It does not disclose whether an existing location is overwritten or how per-keyword overrides interact.

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 dense sentences, all front-loaded with the core action first, then the input mechanism, then the domain-default edge case. Every sentence carries information, though the parenthetical example list is slightly heavy.

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 7-parameter destructive mutation tool with no output schema, the description covers the action, the input alternatives, defaults, and the prerequisite for ranking to work. It stops short of stating what happens to any previously configured location or whether the change applies uniformly across all tracked keywords, which would matter for a destructiveHint=true 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 100%, setting the baseline at 3, and the description adds real value on top: it frames location and location_code as mutually exclusive alternatives ("Pass location ... or a location_code") and explains that a passed name is looked up. This clarifies the relationship between the two location parameters that the flat schema cannot express.

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 ("Set") and resource ("the market every tracked keyword is ranked in") with scope explicitly bounded to all tracked keywords. The country/state/city plus language and device detail makes the action unambiguous and distinguishable from sibling tools like check_tracked_keyword_rankings or add_tracked_keywords.

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?

Provides a clear precondition for use ("a .com/.io with none set must set one before ranking checks run") and explains the fallback behavior for brands with a ccTLD. It does not name sibling tools as alternatives, but the trigger condition for calling this tool is stated plainly.

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