update_pass

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

The destructiveHint annotation already signals mutation, and the description adds specific behaviors like invalidating a pass and adjusting balance. However, it does not disclose additional traits such as permission requirements, reversibility, or side effects on related data. Given the annotation, this is adequate but not rich.

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 two concise sentences that front-load the core action ('Update an existing pass's...') followed by usage examples. Every word contributes value with no redundancy or irrelevant details.

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 tool with 9 parameters and nested objects, the description provides a solid high-level overview of functionality and identification methods. It groups operations into logical categories (fields, stamps, balance) and covers invalidation. The schema handles detailed parameter semantics, so the description does not need to enumerate everything. It is sufficiently complete for an agent to understand when and how to invoke it.

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%, so all parameters are already documented. The description adds a useful identification note ('by ID or by externalId + templateId') which is also present in the schema properties, but it does not introduce new meaning beyond grouping operations into stamps, balance, and fields. This meets the baseline 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 description clearly states 'Update an existing pass's fields, stamps, or balance' with a specific verb and resource. It explicitly lists the modification aspects (fields, stamps, balance) and mentions invalidation, making it distinct from siblings like create_pass, get_pass, and list_passes.

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 provides direct usage scenarios: 'modify customer data, add/remove loyalty stamps, adjust balance, or invalidate a pass.' It implicitly differentiates from creation by specifying 'existing pass,' but it does not explicitly mention when not to use it or name alternative tools for creation, such as create_pass.

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