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

No annotations provided, so description carries full burden. It discloses that the entry is always attributed to the current user and that start_time defaults to 09:00. However, it omits details about idempotency, return values, or error handling, which are important for a create operation.

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?

Two sentences with no unnecessary words. The first sentence immediately conveys the main action, and the second provides essential parameter 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 simple creation tool with no output schema, the description covers the key constraints and required parameters. It is adequate for an agent to understand the basic operation, though it could mention return values or error cases.

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%, baseline 3. Description adds value by stating the default start_time (09:00) and listing the required parameters, though it does not elaborate on the optional text or idempotency_key parameters.

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?

Description clearly states 'Create a new time entry on a subtask for the current user', specifying verb, resource, and scope. It distinguishes from siblings like bulk_create_time_reports and start_timer by focusing on a single entry for the current user.

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?

Mentions that entries cannot be created for another user, providing context for when not to use it. However, it does not explicitly compare with similar tools like log_time or start_timer, leaving the agent to infer the appropriate use case.

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