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

Annotations already indicate idempotentHint=true and destructiveHint=true, and the description adds little beyond that. It does not explain the upsert mechanism (e.g., how customerId triggers update vs create) or any side effects. The '[demo: deshabilitada]' prefix is not elaborated, adding no behavioral clarity.

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?

The description is a single sentence and mostly to the point, but the leading '[demo: deshabilitada]' flag is extraneous and may confuse. It still earns a 4 for brevity, though the flag undermines conciseness slightly.

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 7 parameters, no output schema, and a mutation operation, the description is too minimal. It fails to mention the critical behavior that omitting customerId creates a new customer while providing it updates an existing one. This information is only in the schema, and the description does not integrate it, leaving a significant gap in completeness.

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 covers 100% of parameters with descriptions, so the schema already documents each field. The description does not add additional parameter semantics, so it stays at the baseline for full schema 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 description clearly states the tool's action ('Creates a new customer or updates an existing one') and its resource ('customer'). This distinguishes it from siblings like delete_customer and find_customer, and includes the scope 'for the authenticated business'.

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 description implies usage for creating or updating a customer, but does not explicitly mention alternatives or when-not-to-use. It lacks guidance on when to prefer find_customer or delete_customer, leaving usage to be inferred from the verb 'upsert'.

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