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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context beyond this: the source is Apple Reminders on this Mac, it lists reminders, and it supports optional filtering. This gives the agent a clear picture of what the operation does without contradicting the annotations.

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 description is three sentences with no filler. It front-loads the core purpose, then adds filtering options, then provides the key alternative. Every sentence earns its place and the structure is easy to scan.

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?

Given the annotations cover read-only safety, the schema covers all parameter semantics, and an output schema exists, the description is complete for an agent to select and invoke the tool correctly. It also includes the most relevant sibling differentiation, making it fully sufficient in context.

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 100%, so the schema fully documents all three parameters. The description mentions filtering by completion status or list name, which adds no new meaning beyond the schema. Baseline 3 is appropriate because the description does not need to compensate for any schema gaps.

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 uses a specific verb and resource: 'Lists reminders from Apple Reminders (Reminders.app) on this Mac.' It also mentions optional filtering by completion status or list name, making the tool's scope and capabilities immediately clear. It further distinguishes itself by pointing to todo_list_tasks for Microsoft To Do, eliminating ambiguity among task-related siblings.

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 explicit guidance on when to use this tool versus an alternative: 'For Microsoft To Do use todo_list_tasks instead.' This directly tells an agent which sibling to pick for a different system. The tool is clearly scoped to Apple Reminders, so an agent can infer when not to use it.

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