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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower; the description adds genuinely non-obvious context: the GSC integration prerequisite, a concrete remediation URL, and how the property is resolved when multiple Google accounts are connected. It doesn't cover result size or what happens when no pages match, but the account-resolution and auth details are the harder-won information.

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?

Four sentences, front-loaded with the purpose before prerequisites, and each sentence carries distinct information (concept, use case, auth prerequisite, multi-account behavior). The second clause is mildly redundant with the first, but it aids comprehension rather than padding.

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 7-parameter read-only analytics query with a fully documented schema, the description covers what an agent needs to decide and call: what it returns conceptually, the integration prerequisite, and account-resolution behavior. No output schema exists, so some detail on the returned page rows is missing, but nothing blocking remains.

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 every parameter (site, date range, maxCtr, minImpressions, rowLimit, searchType) is already documented with defaults and formats. The description reinforces the semantics of the impression/CTR pair conceptually but adds no threshold values, syntax, or edge-case guidance beyond the schema. 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 ("Find pages") plus the exact filter concept: high impressions, low CTR. The plain-language gloss ("Google is showing frequently but users aren't clicking") makes the heuristic unambiguous. It does not name the closely related sibling get_gsc_low_ctr_queries, so the page-vs-query distinction rests on the tool name alone.

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?

"Good starting point for title/description rewrites" gives a concrete when-to-use scenario tied to a real workflow. It stops short of exclusions or naming alternatives such as get_gsc_low_ctr_queries or get_gsc_opportunity_queries, so an agent must infer which granularity to pick.

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