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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description adds real value beyond them: it discloses that per-item names and nutrition are returned, that the shape matches get_today, and that each `recent` item carries an `id` usable with update_log. It does not cover what happens when nothing was logged on that date or how an invalid/future date is handled.

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?

Three short sentences, front-loaded with what the tool returns, followed by the question it answers and the follow-up action it enables. No filler; the one unusual device (capitalized INCLUDING) is doing real work by flagging that payload detail.

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?

With no output schema, the description carries the return-value burden and mostly meets it by describing included fields and deferring shape to get_today. The reliance on a sibling's documentation is a slight indirection, and edge cases (empty day, bad date) are left unstated, but an agent has enough to call this correctly.

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% — the single `date` parameter is documented with a YYYY-MM-DD regex pattern and format note. The description adds only the natural-language framing ('yesterday / on <date>') and no format, timezone, or boundary semantics beyond the schema, so the baseline of 3 applies.

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 verb and resource ('Everything logged on a specific day') and narrows scope by calling out that food names and nutrition are included. It differentiates from siblings by anchoring the return shape to get_today and by naming update_log as the corrective follow-up.

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?

Gives an explicit use case in the user's own words ('what did I eat yesterday / on <date>'), which tells the agent exactly which question routes here. It stops short of an explicit exclusion ('do not use for today — use get_today'), leaving that switch to be inferred from the date parameter and the shape reference.

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