Read the user's habits

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description goes beyond that by explaining the shape of the response, including the notable 'available' field that returns the broader habit catalog the app offers rather than just enrolled habits, which is genuine behavioral context.

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?

A single front-loaded sentence leads with the core action and then documents field meanings tersely in parentheses. There is little waste; density of field detail is justified given the lack of parameters.

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 zero parameters, full annotation coverage, and an existing output schema, the description supplies more than the minimum by glossing fields and flagging the 'available' catalog. Nothing an agent needs in order to call it correctly is 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?

The tool takes zero parameters, so the baseline is 4. There is nothing for the description to clarify regarding inputs, and it appropriately spends its words on output structure instead.

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 states a specific verb (Read) and resource (the user's habits) with a concrete example ('drinking water every day') and enumerates the fields returned. It is unambiguous what the tool does. It does not name a sibling to differentiate from, but no sibling tool overlaps with habits, so this is a minor omission.

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?

Usage is implied by the read-only listing nature of the tool, but there is no explicit when-to-use, when-not, or alternative named. An agent can infer intent, but nothing routes it away from other read tools if ambiguity arose.

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