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

With no annotations, the description carries the full behavioral burden. It usefully discloses that results are "always personal" (no workspace scoping) and that the date defaults to today, but it never states that the call is read-only, whether there is pagination or a result limit, or how routines are represented relative to habits.

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?

It is a single sentence with no padding, and the resource is front-loaded. But the clause structure ("and for habits whether they're done on a date...") is grammatically tangled and forces re-reading to parse habits-versus-routines behavior.

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 no output schema and no annotations, the description must explain the return shape, and it does partially (days, times, done-on-date, streak). It leaves ambiguous whether routines are returned alongside habits, whether done-status applies to routines, and any ordering or volume expectations.

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 already 100%, but the description adds real meaning: the date controls which day's completion status is reported and defaults to today if omitted. That is semantics the schema's bare "YYYY-MM-DD" string does not convey.

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 habits and routines") and enumerates the returned fields, so the agent knows what data comes back. However, it never states the operation as a verb (list/retrieve) and does not distinguish this tool from the sibling list_routines, which appears to overlap on the routines half of the same data.

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?

There is no when-to-use guidance, no mention of when to prefer list_routines, and no pointer to create_habit/log_habit for writes. The agent must infer usage entirely from the tool name and the described payload.

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