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

With no annotations supplied, the description meaningfully discloses that this reads published criteria, provides a GET HTTP equivalent, and is free with no x402 challenge. It does not expressly label the operation read-only, although the wording and GET equivalent make that behavior strongly inferable.

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 description is front-loaded with the resource and returned content, then covers workflow timing, payment behavior, and the HTTP equivalent. It is compact and relevant throughout, though the parenthetical service identifiers and dash-separated fragment make it somewhat dense.

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 zero-input criteria read without an output schema, the description still identifies the returned information, service version and operation, workflow purpose, cost, and transport equivalent. This is sufficient to select and invoke the tool correctly, with explicit sibling names being only a minor possible enhancement.

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?

There are no parameters, so the empty schema fully defines the invocation and requires no parameter explanation. The description usefully adds direct-call and payment context rather than redundantly documenting schema fields.

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 identifies the resource as the published criteria for the True Cost service and specifies its contents: the per-facilitator fee model, its source and vintage, and the pinned public test corpus identity. It clearly implies a criteria read rather than quote generation, but does not explicitly differentiate itself from true_cost_quote or true_cost_precheck.

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?

"Read these before paying" provides a concrete point in the workflow, while "call directly without payment" clarifies invocation. It does not explicitly direct agents to true_cost_quote for quotes or true_cost_precheck for preflight, so sibling-selection guidance remains implicit.

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