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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered structurally. The description adds one genuinely new fact — that the call is FREE (no cost/credits) — which is not in the annotations. It says nothing about rate limits, auth requirements, or what 'commerce policy' contains.

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?

Two compact sentences, no filler, and the key qualifier (FREE read-only) is front-loaded before the routing hint. Every clause earns its place.

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 values need not be described. But for a zero-param discovery tool the description leaves the domain ambiguous — 'provider' and 'commerce policy' are undefined, and no distinction from provider.get or marketplace.describe is drawn, which is the main thing an agent needs.

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 tool takes zero parameters, so the baseline is 4 and there is no parameter meaning for the description to supply or omit.

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 concrete verb-resource pair ('provider and commerce policy discovery') and states the scope (read-only, free), which is more than a tautology of the title. However, it does not distinguish itself from close siblings like provider.get, marketplace.describe, or capability.search, so an agent cannot route on the text alone.

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?

'Use this before selecting an offer or capability' gives a sequencing cue, implying usage ahead of offers.list/commerce.quote. But it names no alternative tool and gives no when-not-to-use condition, so the guidance is implied rather than explicit.

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