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

Annotations already declare readOnlyHint=false, destructiveHint=true, idempotentHint=true, and openWorldHint=true, so the safety profile is partly covered. The description usefully adds the downstream consequence that Keyword Planner data activates on completion, but it never explains the destructive aspect, the link's expiry/reuse behavior, or what happens if the site is already connected — the tension between 'Get the OAuth link' and destructiveHint=true is left unaddressed.

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?

Two tight sentences with the purpose front-loaded; the second sentence delivers real context rather than filler. 'Xyle's developer token is approved' is slightly promotional and could be trimmed, keeping it just short of a 5.

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 one-parameter connect tool the definition tells the agent what it returns (an OAuth link), what it connects (Google Ads to a site via site_id), and the payoff after the handshake. With no output schema required for such a simple flow, nothing essential is missing for a correct invocation.

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% for the single site_id parameter, and the description neither names it nor adds format/constraint detail beyond the schema. Baseline 3 is appropriate when the schema fully carries the parameter documentation.

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 names a concrete verb and resource: it returns an OAuth link so the user can connect a Google Ads account to a site. That is far more specific than a tautology, and the effect (Keyword Planner activation) rounds out the purpose. It does not, however, explicitly contrast itself with the nearby get_google_ads_status or the other connect_* siblings, so differentiation relies partly on the tool name.

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?

Usage is only implied: the agent can infer 'use this to connect Google Ads,' but there is no statement of when to call it versus checking existing status (get_google_ads_status) or reconnecting an already-linked site. No prerequisites or exclusions are mentioned, leaving the routing decision to inference.

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