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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered elsewhere. The description adds useful context that the payload matches a specific public HTTP endpoint and names the data categories returned, but says nothing about auth needs, rate limits, or caching.

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 with the resource and returned data categories front-loaded. The endpoint equivalence note earns its place as a concrete reference for the same data, and there is no filler.

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-parameter discovery tool with no output schema, the description gives enough to know what comes back (prices for listing/renewal/takeover minimum, payment rails, refund policy). It stops short of describing the response shape, which would help an agent plan downstream calls.

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. The description correctly implies no input is needed, and there is no parameter content to document.

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 verb and resource ('get pricing' for the 'Promo Board') and enumerates what the data covers: listing, renewal, takeover minimum, rails, refund policy. This clearly differentiates it from mutation siblings like promo_create_listing and promo_takeover_top_spot, though it doesn't name them 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?

The 'Discovery:' prefix implies this is an exploratory read to perform before acting (e.g., before listing or taking over a spot), but it never states when to use this versus promo_get_listing or promo_search_listings. Usage is inferable rather than explicit.

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