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

Annotations already declare readOnly, idempotent, closed-world, and non-destructive, so the safety bar is low. The description still adds real value: it states the tool cannot purchase or change subscriptions, and that business pricing is quoted rather than published, which tells the agent the returned dataset has a known coverage gap.

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 short sentences, zero filler. The positive capability is front-loaded and the constraint follows immediately, so an agent reads the scope and the limit in one pass.

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 read tool with an output schema and full annotation coverage, the definition covers purpose, content scope, and the mutation boundary. Nothing essential is missing, though it does not mention currency/region or data freshness, which an agent might still want.

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 there is nothing for the description to disambiguate. The baseline of 4 applies; no parameter semantics are missing.

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?

"Read published plans and credit policy" names a specific verb and a specific resource, and the second sentence scopes the content boundary (business pricing is quoted, not published here). The resource is clearly distinct from the sibling documentation/product-facts/skills tools, though it does not 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?

Usage is implied by the verb (read pricing when you need plan or credit information), and the exclusion of business quotes hints at when this tool will not answer. There is no explicit "use this when..." or a named alternative for business pricing, so guidance stops short of a 4.

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