todo_update_task

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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, so the safety profile is known. The description adds genuinely non-obvious behavior: this is a partial/PATCH-style update where omitted fields are preserved, and dates are cleared by passing an empty string rather than being left out. It still doesn't say what the call returns or whether clearing a date is reversible.

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 short sentences, zero filler, and the most load-bearing rule ('Only supplied fields change') is front-loaded immediately after the purpose statement. Each sentence adds distinct information.

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 10-parameter mutation tool with no output schema and zero schema descriptions, the description covers patch semantics and date clearing but leaves identifier semantics and most field behavior unaddressed. An agent could call it correctly for status/date changes but would be guessing on identifiers and categories.

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% for 10 parameters, so the description must compensate. It resolves the two most dangerous ambiguities — null/omitted means 'unchanged' and empty string means 'clear' for due/start/reminder — but says nothing about task_id vs list_ref, categories, importance, notes, or the other three status enum values, leaving half the surface undocumented.

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 a specific verb and resource ('Update a To Do task') that clearly separates it from todo_create_task and todo_get_task, and the 'To Do' qualifier implicitly separates it from planner_update_task. It does not explicitly address the nearest sibling, todo_move_task, or say when a move should be preferred over an update.

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 gives strong operational rules for *how* to use fields (only supplied fields change, empty string clears a date, status='completed' vs 'notStarted'), which is real usage guidance. It gives no guidance on *when* to choose this tool over alternatives such as todo_move_task or planner_update_task, so usage is only implied at the selection level.

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