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

With no annotations, the description carries the full burden and does well: it discloses the batch cap (25, or 100 on Pro+), the per-query API cost, the plan requirements for different query types, and that amounts are in cents. It omits error/partial-failure behavior, which keeps it from a 5.

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 tight sentences, front-loaded with the batch limit and cost, then query formats, then plan gating. Every sentence carries information; 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?

No output schema and no annotations, so the description must stand alone, and it covers limits, cost, plan gating, query formats, and units. It could say more about output shape or how partial failures are handled, but the essential call-time information is present.

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 coverage is 50% and the undocumented 'queries' parameter is precisely what the description explains — listing id, tracked item slug, category, or free text naming a tracked item — with concrete examples. The 'state' default is already in the schema, so the description compensates for the coverage gap well.

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+resource+scope: 'Up to 25 sold_comps lookups in one call', which cleanly separates it from the single-lookup sibling sold_comps. It does not name the sibling explicitly, so it stops just short of 5.

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?

Plan gating ('Item-level and per-listing answers need Pro or Pro+; categories work on every plan') gives real context for when the tool functions, but there is no explicit statement of when to prefer this over sold_comps versus making repeated single calls. Usage is implied by 'in one call' rather than stated.

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