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

Beyond the annotations, it discloses the return artifacts (days-to-go numbers, PDF, ICS file), the reminder schedule (100, 50, 30, 14, 7, 3, and 1 days before plus event day), and the 400-day limit. This gives the agent useful behavioral context for a read-only generation tool.

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 front-loaded with use cases and key parameters, then moves into styles and limitations. It is dense but well organized; the main inefficiency is repeating style details already present in the schema.

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 12-parameter generation tool with annotations and an output schema, the description provides enough context to call it correctly. It covers the core inputs, output artifacts, limits, and exclusions without needing to explain every return field.

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%, and the description largely repeats the schema's parameter documentation, especially for style, weekdays_only, and skip_dates. It does reinforce that event_date is required and start_date defaults to today in the user's time zone, but it adds little meaning beyond the already detailed schema.

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 combination: it generates printable countdown calendars. It enumerates concrete variants (grid, chain, tear_off) and explicitly distinguishes the tool from a live countdown timer or notification scheduler.

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?

It gives explicit when-to-use examples, including printable paper chain countdowns, vacation and wedding countdowns, advent-style calendars, and school days left until summer break. It also states when not to use the tool: no notifications, phone timers, or hour/minute countdowns.

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