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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false), so the description's real value is the semantic behavior it adds: a partial day means missing meals and its totals are only a lower bound, and an unlisted day means 'unmarked.' That is meaningful context beyond the annotations, though it does not discuss permissions or pagination.

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 sentences, front-loaded with the core purpose, then interpretation rules. Every sentence carries distinct, actionable information with no filler.

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, return values need not be explained, and annotations cover safety. The description supplies the remaining needed context: interpretation of partial vs unmarked days and the pre-averaging usage rule.

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% (each param already documented as inclusive, format=date), so the baseline is 3. The description adds 'local dates,' clarifying the timezone semantics of the boundaries beyond what the schema states.

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 (Read) and resource (which days were marked fully or partly logged), with the date range scope defined. It is immediately distinguishable from list_meals/list_foods/get_meal siblings because the resource is day-level log status, not meals or foods.

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?

Explicitly instructs to 'Read this before judging or averaging past days,' names the exclusion ('unless already read in this conversation'), and warns to leave partial days out of averages/trends. Both the when and the when-not are stated.

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