planner_items

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds meaningful behavior beyond that: chronological unification across item types, pre-computed submission state per item, and the default date window of today through seven days. It does not discuss pagination or result limits, which keeps it from a 5.

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 lead sentence front-loads the core identity, and the Args block is compact and scannable. The informal 'what's on my plate' framing is slightly loose but earns its place by conveying scope quickly; nothing is redundant.

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 an output schema present, the description needn't explain return values, and it covers all four parameters plus the aggregation behavior. It is nearly complete for a read-only feed tool; only edge behavior like empty windows or result caps is unaddressed.

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%, so the description must carry the parameter burden, and it largely does: it gives the YYYY-MM-DD format and default window for start_date/end_date, an example value for context_codes, and the meaning of filter_new_activity. The only soft spot is 'fresh updates' for filter_new_activity, which is not precisely defined.

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 a specific resource (a unified planner feed) and enumerates exactly what it aggregates: assignments, quizzes, discussions, announcements, calendar events, and user notes, unified chronologically with submission state pre-computed. This clearly distinguishes it from siblings like list_assignments or list_announcements, which return single item types.

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 phrase 'One call returns...' implicitly positions this as the aggregate alternative to the per-type list tools, giving an agent a clear reason to pick it. However, it never explicitly states when NOT to use it or names a sibling alternative, so the routing guidance is inferred 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.