Performance By Search Appearance

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

With no annotations, the description carries the full burden. It usefully discloses a request-level limitation (the dimension cannot be combined, hence no filters argument), which is genuine behavioral context. However, it says nothing about read-only nature, permission scope, pagination, or result ordering.

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 sentences, front-loaded with the core purpose and followed by the single most surprising design fact. No filler, no restatement of the title.

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?

An output schema exists, so return values need not be described, and the schema fully documents parameters. The description supplies the one non-obvious constraint about dimension incompatibility. Minor gaps remain around result ordering and how appearance types are enumerated, but nothing blocking.

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 end_date, site_url, row_limit, start_date and search_type are all documented in the schema itself. The description adds no parameter-level detail beyond explaining the deliberate absence of a filters argument, so the 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 and resource ('Performance broken down by search appearance') and clarifies the dimension with 'rich result types'. The dimension name inherently distinguishes it from parallel siblings like performance_by_date, performance_by_country and performance_by_device, though it never names them explicitly.

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?

The note that SEARCH_APPEARANCE cannot be combined with other dimensions gives a real usage constraint, but there is no explicit statement of when to pick this tool over the parallel performance_by_* siblings or what the intended scenarios are. Usage is only implied by the groupby dimension.

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