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

Annotations only cover the safety profile (readOnly, idempotent, non-destructive), so the description carries the rest and does so richly: fixed 20-record pages with no limit argument, oldest-first history, later completed Scans excluded from continuation, invalidated cursors after repairs, UTC calendar-day metric dates vs completedAt finish time, and null subjectContext for legacy Scans. This is genuinely additive behavioral disclosure.

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?

Front-loaded with what the tool returns before operational caveats, and each sentence carries content that matters for a 15-parameter paginated tool. It is dense and compresses many independent rules into one paragraph, which slightly hurts scannability.

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 explanation is not required, and the description still covers pagination, cursor lifecycle, date semantics, and subjectContext. It never addresses how this tool relates to the visibility/narrative siblings, which is the main remaining gap for a tool of this complexity.

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 93%, so the schema already documents every parameter. The description's notes on cursor behavior and UTC date semantics largely duplicate the schema text, and 'subjectContext' is a response field rather than a parameter. The only marginal addition is the explicit 'no limit argument' note, so baseline 3 is correct.

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+resource (get a brand scorecard) and enumerates the metric families returned (visibility, Share of Voice, signed sentiment, gap, composite health) plus the record grain (one Scan × entity). It is clearly distinguishable in content from overview/timeline siblings, though it never names an alternative 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?

Gives operational use guidance (follow nextCursor with unchanged filters; restart after metadata or evidence edits) but says nothing about when to pick this tool over get_visibility_overview, get_visibility_timeline, or get_model_breakdown. Usage context is implied by the metric list rather than stated.

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