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

Annotations already declare a non-read-only, non-idempotent, non-destructive write. The description adds two pieces of context annotations do not carry: an authentication requirement and a confirmation-before-writing norm. It stops short of warning that repeat calls likely create duplicate entries given idempotentHint=false.

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, front-loaded sentences with no wasted wording; the precondition leads and the action follows. It is efficient and easy to scan, though the terse phrasing is more clipped than polished.

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?

For a write tool with no output schema and half-documented parameters, it covers auth, target resource, and a confirmation step. What is missing is the consequence of repeated invocation and the shape of a successful result, which an agent calling a non-idempotent logging tool would benefit from knowing.

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 50%; date and profile_id are documented inline (including "From get_my_health"), while weight and unit are not. The description obliquely references "the number" (weight) and "one of the customer's health profiles" (profile_id), adding marginal meaning beyond the schema but not compensating for the coverage gap.

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 ("Record a weigh-in") scoped to the customer's health profiles. It is clear on its own, but it never distinguishes itself from the closely related sibling import_weights, so an agent must infer the single-entry vs bulk distinction.

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?

"Requires signing in with a Deer account" and "Confirm the number with the person first" give a prerequisite and a caution, which is real context. However, there is no guidance on when to pick this over import_weights or how it pairs with get_my_health, so usage is only implied.

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