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

Annotations already indicate this is a non-read-only mutation. The description adds valuable behavioral context: the new locale starts empty, and the operation requires the Scale plan or higher. It does not contradict annotations and provides useful entitlement and initialization behavior beyond the schema.

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 short sentences, front-loads the core action, and contains no filler. Every word earns its place: it states what is created, how it starts, and what plan is required.

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 simple creation tool with complete schema descriptions, a plan requirement, and an output schema, the description covers the essential context. It does not explicitly mention what happens if a duplicate locale is created, but the schema already notes that a course can have only one translation per locale, so this is not a critical gap.

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%, with both courseId and locale already described clearly, including example values and the uniqueness constraint. The description does not add additional parameter-specific semantics, so the baseline score of 3 is appropriate.

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 uses a specific verb ('Starts') and a clear resource ('a new (initially empty) locale for a course'), making the operation unmistakable. It distinguishes itself from sibling tools like update_translation, get_translation, and delete_translation by framing this as the creation of a new, empty locale.

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 when to use it: when a new locale/translation should be created, as opposed to updating or deleting an existing one. However, it does not explicitly name alternatives or state conditions like 'use update_translation to modify an existing locale.' The Scale plan requirement is a useful prerequisite, not an explicit usage-vs-alternative guideline.

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