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 that probes are live, what is compared, the [FREE] cost tag, and enumerates the verdict categories (HONEST/OVERCHARGE/UNDERCHARGE/NO_PAYMENT_WALL/UNREACHABLE). It omits any note on rate limits, caching freshness, or auth, but the behavioral picture is substantially richer than the bare name implies.

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 [FREE] tag and core purpose are front-loaded, and the sentences each carry information (mechanism, dual-mode behavior, verdict set). Slightly long with the program URL tail, but no wasted sentences.

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?

An output schema exists, so return-value explanation is not strictly required, yet the description helpfully names the verdict enum. For a single-optional-param read tool the definition is essentially complete; only explicit routing against sibling directory tools 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 0% and slug has no description in the schema, yet the prose fully disambiguates it: no slug returns every listed service's latest verdict, a slug returns that single service's verdict. This compensates completely for the missing schema documentation.

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?

States a specific resource (Price Honesty Badge status for the AgentPay Directory) and explains the underlying mechanism (live-probing endpoints and comparing quoted vs advertised price). It is clear enough to distinguish from most siblings, but it never explicitly contrasts itself with the closely-named agentpaystore_directory tool.

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?

The description clearly explains how the tool's behavior changes with vs without a slug, which is genuinely useful. However, it offers no when-to-use framing against alternatives (e.g., agentpaystore_directory, marketplace_check_endpoint) and no exclusions, so selection guidance is only implied.

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