get_index_coverage

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

Annotations already declare this as a read-only, idempotent, non-destructive operation. The description adds important behavioral context beyond annotations: there is no bulk coverage endpoint, so results are sampled, and the limit has a maximum tied to GSC_MAX_BATCH_URLS x 5. This prevents the agent from mistaking the output for exhaustive coverage 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?

The opening sentence is front-loaded with the core purpose, and the Args list is compact and necessary because the schema itself has no parameter descriptions. Every section adds useful information without unnecessary repetition.

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 value details are not needed in the description. The description still provides enough context about sampling behavior, source selection, scope defaults, limits, and filtering for an agent to invoke the tool correctly.

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 0%, so the description carries the full burden of explaining parameters. It documents all seven parameters, including defaults, the source choices, how urls overrides source, sitemap default behavior, the limit cap, the days window, and examples for issue_filter.

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 and resource: a coverage report built from live URL Inspection that groups URLs by Google's coverage state with counts and example URLs. It is clear and actionable, but it does not explicitly distinguish this tool from sibling tools such as check_indexing_issues, inspect_url_enhanced, or batch_url_inspection.

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 description explains the sampling mechanism and the three practical sources: top pages, sitemap, or an explicit URL list. It also clarifies defaults and override behavior for source selection, but it does not explicitly say when to use this tool instead of sibling indexing or inspection tools.

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