AI assistant traffic

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful methodological context (session-source matching rather than channel grouping catches referrals other tools miss), but says nothing about auth needs, rate limits, or latency.

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?

A single dense sentence for the method plus a compact enumeration of returned sections. It is front-loaded and wastes little, though the return-value list is somewhat crammed.

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?

With no output schema, the description usefully enumerates the return shape (totals, share of sessions, per-assistant breakdown, top landing pages, daily trend). However it omits any parameter guidance for three of four inputs, so it is incomplete for 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 description coverage is only 25% (only property is documented), so the description carries the burden of explaining top, startDate, and endDate. It mentions none of the parameters, leaving the date-range and result-limit semantics entirely to undocumented schema fields.

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 states a specific verb+resource (GA4 sessions referred by AI assistants) and even explains the measurement basis (session source vs GA4 channel grouping). This clearly separates it from a generic GA4 report, though it never names a sibling like ga_report to route against.

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 implied by the narrow scope (AI-referred traffic only), but there is no explicit when-to-use or when-not guidance and no naming of the alternative reporting tool (ga_report, ga_realtime). An agent must infer the choice from scope alone.

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