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

Annotations only say it is a non-read-only, non-destructive, non-idempotent write; the description adds the auth prerequisite, the dedup behavior ('days already logged are skipped'), and a required human confirmation step — genuinely useful context beyond the hints. It still does not say what happens to partially invalid entries or what a failed import returns.

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?

Four short sentences, each carrying a distinct load, with the auth prerequisite front-loaded before the operational detail. No filler or restatement of the tool name.

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?

Covers the mutation's key prerequisites and confirmation flow, which is the most important gap for a write tool. However, with a nested entries array, a unit parameter, and no output schema, the description leaves the per-entry input format and error/partial-failure behavior to the 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 only 33%, but the description compensates partially by implying entries are dated weigh-ins ('days already logged are skipped') and listing plausible sources (scale app, spreadsheet, photo). It gives no guidance on the unit enum, the lb default, or the 500-entry cap beyond what the schema already 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 concrete verb and resource: 'Add many past weigh-ins at once', with the bulk nature distinguishing it from the single-entry sibling log_weight. It never names that sibling explicitly, so differentiation is implied rather than stated.

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 real operating context: a Deer account sign-in is required, and the agent is told to show the list and get the person's OK before committing. It does not name log_weight as the alternative for a single weigh-in, nor state when import is inappropriate.

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