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

Annotations already declare the safety profile (readOnlyHint=false, idempotentHint=false, destructiveHint=false), so the bar is lower, and the description adds a genuine side-effect disclosure: that remind_at causes a reminder to pop on the user's devices. That outcome is not derivable from the annotations or schema. It stops short of covering failure modes or whether the to-do is synced across devices.

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 short sentences, zero filler, and the core purpose is front-loaded ahead of the optional-parameter behavior. Every clause carries 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?

The tool is simple (2 params, 1 required, no nesting), annotations carry the safety profile, and an output schema exists so return values need not be described. The description covers purpose and the reminder side effect; the only gap is the implicit distinction between personal to-dos and workspace items created by create_item.

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 100%, so the baseline is 3 and both parameters are already documented in the schema. The description adds meaning beyond the schema by explaining the observable effect of remind_at (a reminder firing on devices), which tells the agent what setting that field actually accomplishes.

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 ('Adds to your personal to-do list'), which cleanly separates it from siblings like create_item, add_comment, and update_todo. It does not, however, explicitly name an alternative or state why a personal to-do differs from a workspace item, so the differentiation is implicit rather than spelled out.

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 'your personal to-do list' implies the usage context (personal to-dos rather than workspace items or comments), but there is no explicit when-to-use, when-not-to-use, or named alternative such as update_todo or create_item. Usage must be inferred from the scope wording.

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