[Write] Update TestFlight "What to Test" notes

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

With no annotations, the description carries the full burden for behavioral disclosure. It reveals an important prerequisite (localization must exist) and Apple's automatic creation behavior. However, it does not mention what happens if the localization does not exist, whether the update is idempotent, or any permission requirements. This is decent but not comprehensive.

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 sentences, front-loaded with the operation type ('Write') and a clear action. No unnecessary information, every sentence contributes useful context.

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?

Given the tool's moderate complexity (4 required params, no output schema, no annotations), the description covers the essential behavior and key prerequisite. It lacks details on return values or error handling, but those are less critical for a simple update operation. The pointer to the get tool helps complete the workflow context.

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?

The input schema has 100% description coverage, so the baseline is 3. The description adds some context by tying the 'locale' parameter to the prerequisite that localization must already exist, but it doesn't add substantial meaning beyond the schema descriptions.

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 function: 'Updates the "What to Test" notes shown to testers for a build/locale.' It uses a specific verb ('Updates'), identifies the resource (build/locale localization), and explicitly differentiates from the sibling tool asc_beta_build_localization_get by directing users to check existence first.

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 gives explicit usage context: the localization must already exist, and points to asc_beta_build_localization_get as a prerequisite check. It does not explicitly list situations where the tool should not be used, but the guidance is sufficient for most agents.

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