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

With no annotations, the description must disclose behavior. It mentions the subtask inherits billing type and that time entries are logged against it, which is helpful. However, it does not discuss return values, error behavior, or permission requirements, leaving gaps.

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 three sentences, front-loading the purpose and then adding context. It is efficient but could be slightly improved with bullet points for clarity. No redundant information, earning its place.

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?

The description does not mention the return value or idempotency behavior, both relevant for a creation tool. Given no output schema, the description should cover what the agent can expect. It provides key facts but is incomplete.

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 each parameter has a description. The description adds value by instructing how to obtain the task_id via find_billing_work, which goes beyond the schema. No other parameters are elaborated, but the schema is sufficient.

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 'Create a subtask under a task,' specifying the verb and resource. It distinguishes from siblings like 'create_task' and explains that subtasks are required for time entries, which clarifies their role.

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 instructs that 'every task needs at least one' subtask for logging time, providing a clear usage context. It also advises to use find_billing_work for IDs, but does not explicitly mention when not to use this tool or list alternatives.

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