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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds genuinely new context beyond that: the data source, the freshness date ('prices checked October 26, 2026'), and what each row contains. It omits ordering and any pagination/result-size 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?

The returned-field inventory leads, followed immediately by the use case, with provenance (source URL, check date) last. The source URL plus date is the only mildly verbose element, though it does earn its place as data-freshness context.

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 correctly carries the return-value burden by listing the per-vendor fields an agent will get. For a single optional enum parameter tool this is nearly complete; only result ordering and whether the list is exhaustive vs. paginated are left unstated.

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?

The single 'category' parameter is fully documented in the schema (100% coverage), so the baseline is 3. The description reinforces the enum semantics by naming 'live, AI and hybrid' as the dimensions the index is sliced by, giving a small but real lift over the schema alone.

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 exactly what the resource is (every answering service indexed by AnsweringPrices.com) and enumerates the returned fields: entry plan, price-publication flag, and pricing-page read date. It also implicitly separates it from get_vendor_pricing by framing the tool's job as 'find a vendor's id'.

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 one explicit use case ('Use it to find a vendor's id'), which tells the agent when to reach for it over fetching pricing for a known vendor. It stops short of naming the alternative siblings (get_vendor_pricing, compare_at_volume) or stating exclusions, so it falls just under the top band.

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