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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description's only addition is the volatility caveat ('Availability can change; do not assume every platform is enabled'), which is useful but modest. It says nothing about auth requirements, rate limits, or caching expectations.

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, both earning their place: the first states what is returned, the second states the volatility constraint. The action and its precondition are front-loaded with no filler.

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 detail is not the description's burden, and annotations cover the read-only safety profile. What remains thin is the relationship to the research workflow — it says 'before researching' but does not tie itself to quote_research, start_research, or scan_intelligence_target, leaving the sequencing partly inferred.

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% — brandId has no description, only a pattern. The description never mentions the parameter or explains that results are scoped to a single brand, so it fails to compensate for the coverage gap. For a single required identifier this is a mild but real omission.

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 ('Check') and enumerates the concrete resources returned: source availability, public ad library allowances, and the current scan credit price. That content distinguishes it from the other capabilities probes (get_automation_capabilities, get_report_capabilities, get_workspace_capabilities) by domain, though it never names or contrasts those siblings 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?

It gives an explicit precondition — call this 'before researching' — which is real when-to-use guidance. It also warns that availability is volatile and should not be assumed, which tells the agent to call rather than guess. It does not name alternatives such as quote_research or start_research, so it stops short of full routing guidance.

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