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

Annotations already indicate destructive=true, but the description adds valuable context: it rebuilds the .pkpass file with voided: true, sends push notifications to devices, and notes scope and API mapping. This goes beyond annotations and informs the agent of side effects.

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 moderately sized but every sentence adds value: action, effect, wallet selection, scope, API mapping, and a caution not to invent paths. It's well-structured with front-loaded purpose.

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 void operation with no output schema, it explains the process, device impact, and parameter behavior. It doesn't describe the response, but that's a minor gap given the operation's simplicity and the existing annotations.

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 coverage is 100%, so the schema documents all parameters. The description adds meaning for wallet_type (explains default and when to use) and serial_number (uniqueness), which is beyond the schema. It doesn't repeat schema text verbatim.

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 states a clear verb (void) and resource (pass by serial number), and distinguishes itself from siblings like voidPass and updatePassBySerial. It explicitly mentions the lookup method and the action, leaving no ambiguity.

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?

It provides when to use this tool (void a pass by serial) and includes a specific scenario for the wallet_type parameter (when both Apple and Google passes exist). It doesn't explicitly state when not to use it, but the purpose clarity and mention of alternatives in sibling names imply the context.

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