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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the description's 'Does not change anything' is largely redundant. What it adds is genuinely behavioral: each block explains why it is empty when it has no data, and the URL-format requirement warns that Search Console 'may find no rows' if the scheme or form is wrong.

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 purpose and the block inventory are front-loaded in a single dense sentence, followed by the URL-format warning and the related-tools list. Nothing is padding, though the block enumeration is long and could have been tightened without losing routing value.

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 aggregation tool with a full output schema, the description covers the data sources, the empty-block behavior, the URL prerequisite, and sibling routing, so an agent has what it needs to call it correctly. The only minor gap is what happens when the URL falls outside the property beyond 'may find no rows'.

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 coverage is 100%, so the baseline is 3, but the description goes further on the critical url parameter by specifying the exact form ('scheme included') and the constraint that the URL must belong to the workspace's property. It leaves the date-range and compare parameters entirely to the schema, which is acceptable given full coverage.

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 precise verb and resource ('Reports everything Mark knows about one page URL for a date range') and enumerates the exact content blocks returned: Search Console metrics, tracked keywords, audit issues, posts, leads, buyer questions. This lets an agent distinguish it immediately from get_search_performance, get_site_audit, and get_rankings, which each cover only a slice of the same data.

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?

Gives a concrete prerequisite (the URL must be on this workspace's Search Console property or one of its sites) and tells the agent to pass the URL exactly as get_search_performance returns it, scheme included. It closes with a 'Related:' list for routing, but never states when to prefer a sibling over this tool or when not to use it.

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