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

Goes well beyond the readOnly/openWorld/destructive annotations by disclosing the 92-day cap, default range, oldest-first ordering, timezone precedence ('profile zone wins'), per-call cost of $0.05 and API-key requirement. Cost and auth disclosure in particular is valuable context the annotations cannot carry.

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?

Front-loads what is returned before the range constraints, then tacks on cost/auth. Efficient, but the dense nested parentheticals make it slightly harder to scan than a clean multi-sentence form.

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 an output schema present, the description need not explain return values, and it still covers range limits, ordering, timezone resolution, cost and auth. Nothing needed to invoke it correctly appears to be missing.

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, and the description earns an extra point by adding cross-parameter semantics: 'from' alone means a single day, 'place' narrows the venue, and the account-zone-wins precedence for timezone. Only the 'at' and alias relationship remain schema-only.

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+resource ('Food Diary entries') and enumerates the returned fields (what, kind, place, local time, dishes, photo), which cleanly distinguishes it from log_food, update_food, delete_food and attach_food_photo. An agent can tell what this returns without opening the schema.

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 concrete usage context: civil date range in account timezone, 92-day maximum, default of today, and that optional place narrows to one venue. It does not explicitly name read-vs-write alternatives among siblings, but the read semantics are unambiguous.

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