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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false. The description adds genuinely non-obvious behavior beyond that: collection only begins after the next publish, reports take 24-48 hours to populate, and re-enabling resumes prior history rather than starting fresh. It stops short of stating permission requirements or whether enabling has any cost/quota impact.

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?

Four sentences, front-loaded with purpose and followed by rollout behavior, then the one optional parameter that needs explanation. Each sentence carries information; only the parenthetical field list is arguably expendable, so it falls just short of maximum concision.

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 zero-parameter-heavy, non-destructive mutation with full annotation coverage and no output schema, the description supplies what an agent actually needs: the side effect (collection starts on next publish), the latency expectation (24-48h), and idempotent resume semantics. Missing only auth/permission prerequisites, which is a minor gap.

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 baseline is 3. The description earns a bump by clarifying the trigger condition for the optional custom_domain ('when it differs from its published address, e.g. https://example.com'), which tells the agent the format and when to omit it — context the schema's terse 'when it has its own domain' does not fully convey.

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?

Opens with a specific verb+resource ('Turn on the site's built-in visitor analytics') and enumerates what is collected (visitors, page views, traffic sources, devices), so the agent knows exactly what gets enabled. It never names disable_analytics, but the 'built-in' framing clearly separates it from the tracking-tag/connect_data_source siblings.

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?

'No outside account is needed' tells the agent this is not the connect_data_source path, which is a useful disambiguation. However there is no explicit statement of when to prefer this over disable_analytics, install_tracking_tag, or get_growth_dashboard — the enable/disable relationship is only implied by 'If it was turned off before, the same connection resumes.'

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