in_app_purchases_v2_update_instance

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

With no annotations provided, the description carries the full behavioral burden and fails: it never states that this is a mutation, whether the update is partial or full, whether fields are required, what permissions are needed, or whether changes are reversible. The bare HTTP method is the only hint.

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?

Short but defective: the endpoint string is duplicated verbatim in parentheses, which earns nothing, and the remaining sentence only points elsewhere. Brevity here reflects under-specification rather than efficient, front-loaded communication.

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 mutation tool with no annotations, no output schema, and a nested externally-defined body, the description is far too thin — it omits updatable fields, permission/scope expectations, and partial-update behavior. The agent can form the request shape from the schema but not understand the operation's consequences.

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%: both `id` and `body` are documented in the schema, including the same InAppPurchaseV2UpdateRequest reference the description cites. The description therefore adds no parameter meaning beyond the schema, which is the baseline-3 case for high coverage.

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 text is a near-tautological restatement of the endpoint (PATCH /v2/inAppPurchases/{id}) given twice, plus a schema pointer. It conveys no verb+resource meaning beyond what the tool name and HTTP method already imply, and gives no sense of what an 'update' actually changes.

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?

No when-to-use guidance, no prerequisites, and no differentiation from siblings like in_app_purchases_v2_create_instance, in_app_purchases_v2_get_instance, or in_app_purchases_v2_delete_instance. The agent gets nothing to decide whether this is the right tool.

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