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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds the content scope (quality scores and competitive data) but says nothing about pagination, rate limits, or auth requirements beyond the doc link, so it adds only modest context on top of the structured data.

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?

Front-loaded with the core purpose in the opening clause, followed by a compact return-value list and a doc link. Every sentence is short and earns its place, though the field enumeration is partly redundant given an output schema exists.

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 an output schema present, the return-value listing is not strictly necessary, and annotations cover safety; full schema coverage handles the parameters. The only real gap is the absence of sibling differentiation, which the description does not address.

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 all four parameters (compact, customer_id, date_range_start/end) are fully documented in the schema, including the compact-mode behavior and the 30-day default. The description adds no parameter detail; 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?

States a specific verb+resource ("Get keyword metrics including quality scores and competitive data") and enumerates the returned fields (keyword text, match type, quality score, impressions, clicks, CTR, CPC, conversions). It is clearly keyword-level reporting, though it never explicitly contrasts itself with siblings like get_search_terms or get_campaign_performance, so the distinction is inferred rather than stated.

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 when-to-use statement, no prerequisites, and no routing to or from alternatives such as get_search_terms, get_campaign_performance, or get_ad_performance. Usage is only implied by the topic, leaving the agent to guess which performance tool to pick.

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