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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral detail beyond annotations: streaks count from yesterday while today is still open, and times_per_week habits have weekly streaks with streak_unit=weeks.

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 description is two tight sentences with the main purpose front-loaded and the non-obvious streak rules explained succinctly after. Every clause adds useful information and there is no repetition of the schema or annotations.

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 read-only listing tool with one optional parameter and no output schema, the description names the key returned elements and explains a subtle streak behavior. An example of the response shape would add precision, but nothing critical is missing for an agent to select and call this tool correctly.

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?

There is only one parameter, date, and the schema already describes it fully with format and default behavior, giving 100% schema description coverage. The description does not add parameter-level detail, but it does not need to because the schema covers it. Baseline 3 is appropriate.

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 clearly identifies the tool as listing active habits and specifies exactly what it returns: value logged, done status for a date, and current streaks. This distinguishes it from the many other list_* siblings and from habit mutation tools like log_habit and create_habit.

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?

The description implies the read-only use case of checking habit completion and streaks for a date, but it does not explicitly say when to prefer this over alternatives or when not to use it. The context is present, but the guidance is not spelled out.

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