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

Annotations already establish a write operation (readOnly=false). The description adds a critical behavioral trait beyond annotations: re-sending the same date replaces that day's data. No annotation contradiction is present.

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, no filler; the primary purpose is stated first and the critical overwrite caveat follows. Every sentence earns 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?

Given a fully described input schema and annotations, the description contains the key non-obvious behavior (replace-by-date) needed to call safely. A return-value note would be nice but is not necessary without an output schema.

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 schema carries most parameter meaning. The description adds useful context that line items are optional and that the payload represents day totals, but it does not add per-parameter detail beyond the schema.

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?

States a specific action ('Log') and resource ('a day of nutrition'), and clarifies the content: day totals plus optional food-by-food line items. The per-date replacement behavior further distinguishes it from generic daily-entry or logging siblings.

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 domain-specific phrasing implies when to use it, and the replacement sentence signals it works as an upsert for a date. However, it does not explicitly say when not to use it versus alternatives such as update_daily_entry or get_daily_entry.

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