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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds genuinely new behavioral facts: the review is null when there is no listing or no review, access is owner-restricted, a specific credential type is required, and unclaimed workspaces are refused with 403. These are auth and empty-result semantics the structured fields do not carry.

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?

Return content is front-loaded, followed by the null case, the parameter, then access prerequisites — a sensible order. Slightly telegraphic fragments ('Needs a Last Price credential. Needs a claimed workspace:...') and the redundant 'Pass function_id' keep it just short of ideal.

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?

With no output schema, the description carries the return-shape burden and does so, plus auth and failure modes for a simple one-parameter read. The remaining gap is the lack of any statement about how this relates to run_function_review, which matters in a catalog this large.

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 description coverage is 100% and the single parameter already documents itself as 'The pricing function UUID: id on a list_functions result.' The description's 'Pass function_id' merely restates the requirement without adding format, sourcing, or edge-case guidance, so baseline 3 applies.

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 ('Read the latest marketplace review of one of your functions') and enumerates the return payload: the report, listing visibility, and listing id. It is unambiguous what the tool fetches, but it never names its closest sibling run_function_review, so an agent must infer that this reads an existing review while the other presumably triggers one.

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?

Gives concrete preconditions: 'Only the owner can read it', 'Needs a Last Price credential', and 'Needs a claimed workspace' with the specific 403 failure mode for sandbox keys. What is missing is a when-to-use statement relative to run_function_review or list_marketplace_listings, so alternative selection is left implicit.

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