copy_day

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

The description discloses the additive nature ('does not remove existing entries'), which adds behavioral context beyond the annotations. The annotations already indicate not read-only and not destructive, but the description clarifies the specific mutation behavior. However, it does not mention any other side effects, permissions, or limits.

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 extremely concise with three short sentences. Every sentence adds value: the first states the core action, the second explains the additive behavior, and the third documents the parameter. No unnecessary words.

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 simplicity (single optional parameter, additive operation), the description covers all necessary aspects: what it does, its side effects, and how to use the parameter. The presence of an output schema further reduces the need to describe return values. No gaps identified.

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?

With 0% schema description coverage, the description fully compensates by explaining the only parameter 'date': its format (YYYY-MM-DD) and default value. This is meaningful beyond the schema, which only specifies string or null. The description is clear and actionable.

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 action ('Copy') and the resource ('all diary entries from the previous day to the given date'), making the tool's purpose unambiguous. It distinguishes itself from sibling tools like add_food_entry or mark_day_complete, which serve different functions.

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 some usage context by noting that the operation is additive and does not remove existing entries. However, it lacks explicit guidance on when to use this tool versus alternatives, such as when to prefer it over manual entry copying, and does not mention any prerequisites or limitations.

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