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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds non-structured context — that the call is free, has no cost/rate barrier, and that a non-zero unclassified_count is a signal to take a downstream write action. It does not explain pagination/truncation behavior beyond the schema's 'detail' field. Minor tension: 'call any time' implies repeat-safety while idempotentHint=false, but this is not a substantive contradiction.

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?

Three tight sentences, front-loaded with what the tool returns, then the cost/safety note, then the conditional workflow step. No filler or restated boilerplate.

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?

There is no output schema, so the description carries the return-value burden and does so by listing the concrete fields an agent will get. It also supplies the next-step workflow, making it complete for a read-only analytics tool with a 2-parameter schema.

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% — both 'site_id' and the 'detail' verbosity switch are documented in the schema itself. The description implicitly scopes results to a brand but adds no syntax, format, or semantics beyond what the schema provides, so the baseline of 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?

The description names a specific artifact (TOFU/MOFU/BOFU funnel view of a brand's tracked keywords) and enumerates exactly what it returns: per-stage counts, total search volume, average position, top opportunities, and a cluster breakdown. An agent can distinguish this from list_tracked_keywords or tracked_keyword_performance without opening the schema.

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 clear when-to-use guidance ('Free read — call any time to review coverage and gaps') and a conditional follow-up ('If unclassified_count > 0, classify those keywords yourself and store via classify_tracked_keywords'). It does not name alternative funnel/cluster views (e.g. get_keyword_clusters) or state when this view is the wrong choice, so it falls short of full when/when-not coverage.

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