Read the user's profile

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

Annotations already establish this is a read-only, idempotent, non-destructive, closed-world read. The description goes beyond that by disclosing return-time behavior an agent can't infer from schema/annotations: a weigh-in logged today updates weight_kg, units follow the user's app preference, missing values are null, and premium carries both an active flag and end_date. It doesn't mention auth or error behavior, but the added context is meaningful.

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?

The purpose is front-loaded and the sibling routing is placed cleanly at the end, which is good structure. But the bulk is one run-on sentence with dense parentheticals enumerating every field, most of which is redundant given that an output schema exists, so much of the text does not strictly earn its place.

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 zero-parameter read tool with full annotations and an output schema, the description is effectively complete: it explains scope, null/unit conventions, the live-update behavior of weight_kg, and routes to sibling tools. The only shortfall is that it spends effort restating return fields the output schema already carries rather than noting anything about failure modes.

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?

The tool takes zero parameters, so the baseline is 4 by the rubric. The description does not (and need not) add parameter meaning; its detail is all about return fields, which belongs to the output schema rather than to parameter semantics.

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?

The description names the resource (the user's profile) and enumerates exactly what is returned, and it explicitly distinguishes itself from the neighboring get_targets and get_weight_history at the end. The leading framing ('what the user's goals are computed from, for advice') is slightly indirect about the tool's own purpose, but the field list disambiguates it fully from siblings.

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?

It offers a light usage hint ('for advice') and routes the agent to get_targets for daily goals and get_weight_history for weigh-ins, which is genuine sibling differentiation. However, it never states explicitly when to call get_profile versus those tools, so the guidance is implied rather than spelled out.

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