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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds real context beyond them: it returns puzzle number, word length and an empty board, and explicitly never the answer. The UTC-vs-local-date fallback behavior is also disclosed. Return payload shape is described but not, e.g., what happens on replay of the same day.

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 sentences, front-loaded with the usage trigger and ending with the next-step hand-off; nothing is wasted. The middle sentence is long but carries the rules, return contract and time-zone caveat, so the density is justified rather than bloated.

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?

With no output schema, the description does the work of explaining what comes back (puzzle number, length, empty board, never the answer), and all three parameters are contextualized. The one omission is disambiguation from the similarly named start_daily_puzzle sibling in a crowded namespace.

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, but the description adds decision-level meaning: pass time_zone when known so the puzzle follows the player's local date, otherwise it follows UTC. That explains the interaction between time_zone and utc_offset_minutes that the schema documents only in isolation.

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+resource ('start the daily word puzzle' in Weather With Attitude) and describes what the puzzle actually is: guess a hidden cheeky word in six tries. It also names the follow-on sibling weather_word_puzzle_guess, so the agent can place it in the workflow without opening the schema.

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?

'Use this when someone wants to play the daily word puzzle' gives an explicit trigger, and the closing sentence routes subsequent guesses to weather_word_puzzle_guess. It does not, however, distinguish itself from the start_daily_puzzle sibling, which an agent could plausibly confuse with this tool.

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