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

Annotations already declare readOnly/ idempotent / non-destructive / closed-world, so the safety profile is covered. The description adds real context beyond that: provenance (AnsweringPrices.com), a read date (October 26, 2026), per-field URL and read-date attribution, and the fact that terms are summarized from the vendor's own terms page — useful for judging freshness and trust.

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 core content is front-loaded, but the AnswerAmerica sentence about upfront prepaid packages and credit rollover reads as a dangling vendor-specific note with no clear role, and the source/freshness trailer duplicates info loosely. Tightening would improve it.

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?

For a one-parameter read-only lookup with no output schema, the description covers inputs, the shape of the returned data (plans, overage, comparison cost at 50/100/200 calls, billing terms, per-item URL and date), and provenance. Only the guidance on when to reach for siblings 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 coverage is 100%, so the schema already documents the single 'vendor' parameter. The description still earns credit by clarifying that an id OR a name is accepted and giving concrete example values ("PATLive", "Ruby", "VoiceNation"), which is more actionable than the bare schema text.

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 verb+resource (one vendor's published plans, overage, comparison costs and billing terms) and enumerates the returned fields. An agent can distinguish it from list_vendors (plural listing) and compare_at_volume (cross-vendor volume comparison) by the 'one answering service' scoping, though it never names the siblings 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?

Single-vendor lookup is implied by 'One answering service's published plans' and the accepted-id-or-name note, but there is no explicit when-to-use/when-not or pointer to list_vendors for discovering ids or compare_at_volume for cross-vendor pricing. The agent must infer the routing.

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