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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the bar is lower, yet the description adds a genuinely non-obvious behavior: offset-based deadlines re-shift when the wedding date changes. It stops short of saying whether absolute due_date tasks stay fixed (implying they do) or what the tool returns.

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?

Two sentences, front-loaded with the action and immediately followed by the one decision that matters (date vs offset). The parenthetical example duplicates the schema's own wording almost verbatim, a small redundancy that keeps it from a 5.

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 5-parameter additive mutation with no output schema, the description covers the core modeling decision an agent must get right. The remaining gap is that it never says what comes back (e.g. a task identifier) or whether duplicate titles are permitted, which matters for a create tool.

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 60%, and the description reinforces the two scheduling parameters, including the concrete "-42 for six weeks before" example and the offset-follows-wedding-date rule. However, that example largely restates the schema's own offset_days text, and notes/vendor_category get no mention beyond what the schema already says, so added meaning is modest.

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?

"Adds a task to the planner" gives a specific verb plus resource, which is enough to separate it from delete-task, update-task and list-tasks by name alone. It does not explicitly name a sibling or state the boundary, so it stops short of a 5.

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 name and the additive framing, and the deadline sentence implicitly tells the agent to pick one of two scheduling modes. There is no explicit when-to-use vs update-task, no note that this always creates a new task rather than modifying one, and no prerequisites mentioned.

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