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

Annotations already declare readOnlyHint, destructiveHint=false, and openWorldHint, so safety is covered. The description adds genuine behavioral context beyond that: the developer token approval status and the account-connection dependency that gates live data, plus a state-dependent fallback. No rate limits or return format, but solid added value.

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, front-loaded with the purpose before the prerequisite and the fallback note. Each sentence earns its place, though the add_tracked_keywords note is slightly tangential to a status-check 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 single-parameter read-only status tool with full annotation coverage and no output schema, the description covers purpose, prerequisites, and an alternative workflow. Nothing essential is missing, though it never describes what the status values themselves look like.

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?

There is a single parameter with 100% schema description coverage ('The brand/site ID'), so the schema carries the meaning. The description adds nothing beyond what the schema already documents, making the baseline 3 correct.

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+resource: the Google Ads (Keyword Planner) connection status for a site. It is clearly distinguishable from sibling status tools like get_ga_status and get_shopify_status, and it names connect_google_ads as the related mutating sibling.

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?

Explains the condition under which Keyword Planner data becomes live (once the owner connects via connect_google_ads) and gives a concrete alternative path for unconnected sites (generate ideas in-chat and store with add_tracked_keywords). It lacks an explicit 'call this to check whether connected' framing, but the guidance is strong and actionable.

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