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

With only destructiveHint=true in annotations, the description adds essential behavioral context: 'WRITE — creates data' and the condition 'on a timestamp-tracking account' for running timers. It explains the OR exclusivity of hours vs. timestamps. It doesn't mention rate limits or detailed side effects, but given the sparse annotations, it does a solid job.

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 four sentences, each with clear purpose: action+requirements, mode explanations, prerequisite pointer, and REST/write note. It is front-loaded with the core purpose and avoids redundancy with the schema, making it concise and well-structured.

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 8 parameters, no output schema, and only destructiveHint annotation, the description covers the essential invocation modes, required fields, and a companion tool for discovery. It doesn't mention return value or error behavior, but for a create tool with rich schema descriptions, this is a minor gap. Overall it is sufficiently complete for selection and invocation.

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 the baseline is 3. The description adds value beyond the schema by explaining the mode-based relationships between parameters: hours vs. started_time/ended_time vs. timer (omitting both). It also reiterates required fields and points to a sibling for discovery. This integration guidance elevates it above baseline.

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 states 'Create a time entry' with a specific verb and resource, and differentiates from sibling tools like delete, update, and get by explaining the three creation modes (hours, timestamped, or running timer). It also names the prerequisite tool for finding valid IDs, making the purpose unmistakable.

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 explicit parameter combination guidance: 'Provide hours... OR provide started_time... OR omit both to start a running timer.' It also directs users to harvest_list_project_assignments for valid project_id + task_id, giving clear when-to-use and preparation steps. This is strong, actionable usage guidance.

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