Adjust the routine

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

Annotations already declare readOnlyHint=false and destructiveHint=false, so safety is partially covered. The description adds a genuinely useful persistence detail ('Changes persist to data/routine.json'), but it omits whether changes merge or overwrite existing routine fields and does not confirm the write-confirmation behavior the annotations imply.

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 tight sentences: what it changes, when to use it, and where it persists. Front-loaded with the action, no filler, every sentence earns 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 mutating tool with nested objects, zero schema coverage, and no output schema, the description leaves significant gaps: it never explains the nested sub-fields the active parameters carry, nor whether partial updates require an id (activity.id is required inside the object). It is under-specified given the tool's real complexity.

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 description coverage is 0% and there are 3 top-level parameters (sleep, activity, max_scheduled_hours_per_day). The description names the domains but does not explain the nested fields (bedtime, wakeTime, session_minutes, sessions_per_week, weekdays, window) or the unit/format expectations, leaving the agent to infer nested semantics from the schema alone.

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 specific verb (change) and the three concrete resources it mutates: sleep times, daily limits, and a single activity. The sibling set contains reset_routine and apply_schedule, and this description's scoping to three specific fields clearly differentiates it from those.

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?

Provides explicit trigger conditions via example user phrases ('make DSA 60 minutes', 'I want to wake at 6', 'move part-time work earlier'), which tell the agent exactly when this tool is appropriate. It does not name alternatives (e.g. apply_schedule or reset_routine) or exclusions, keeping it out of the 5 tier.

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