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

Annotations already cover read-only/safe (readOnlyHint, destructiveHint=false), and the description usefully adds output-interpretation traits: ctr is a 0-1 fraction, position is a 1-based average, dates are Pacific Time, and the last ~3 days may be incomplete. These freshness and unit caveats are genuinely valuable beyond the structured fields, though some overlap with the schema's dateRange note.

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, front-loaded sentences: purpose first, then usage context, then unit/caveat details. No filler, and the most decision-relevant information (what it is, when to use it) leads.

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 read-only analytics query with 10 fully documented parameters, an output schema, and rich annotations, the description supplies the remaining interpretive context (data freshness, unit conventions, first-party positioning). Nothing essential to correct invocation is missing.

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%, so the parameters are already fully documented in the input schema (filters, dimensions, rowLimit, dateRange, etc.). The description adds meaning about the returned metric units rather than about the parameters themselves, so baseline 3 applies.

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 ('Query the connected Search Console property's Search Analytics') and enumerates the metrics (clicks, impressions, CTR, average position) and breakdowns (query/page/country/device/date). An agent can distinguish it from siblings like get_landing_page_performance or get_ranked_keywords without opening either schema.

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 usage context: 'First-party data — use it for what already ranks, near-ranking queries, and pages with real demand.' This tells the agent when this tool is the right choice. It does not, however, name alternatives or state when NOT to use it, so it falls short of the 5 bar.

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