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

With annotations already declaring readOnly/openWorld=false/destructive=false, the description adds substantial behavior: the 90-day window, the 0.62 relevance threshold, caller-count ranking, and the empty-response contract (status insufficient_evidence plus next_step). It also rules out silent backfilling from search popularity, page views or trending queries, which is material trust context.

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 definition is a single dense paragraph, front-loaded with the core operation before caveats and the empty-args contract. Nearly every clause earns its place, though the paired 'not proof... and not proof...' clause is slightly redundant.

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?

With no output schema, the description carries the return contract and does so well: it explains the returned form (generalised job labels, ranked by distinct callers) and the empty-evidence case with its status/next_step semantics. For a one-parameter read-only tool, nothing an agent needs to call or interpret it is missing.

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% and the single 'limit' parameter (1-50, default 20) is fully documented in the schema. The description says 'Empty args ({}) return the current list', which confirms default behavior but adds no further detail about the limit parameter. 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?

The description gives a precise verb and resource: it inspects searches by external callers in the last 90 days that returned no or weak matches (relevance below 0.62), rendered as generalised job labels ranked by distinct callers. That is far more specific than the name/title alone. It never names or contrasts with a sibling (e.g. market_gaps), so it stops short of full sibling differentiation.

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 offers interpretation guidance ('Most entries come from a single caller: treat those as leads') and a negative usage note ('Not a prerequisite for choosing a product'), implying context. However, it never states explicitly when to prefer this tool over alternatives such as market_gaps or find_market, leaving routing to inference.

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