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

Annotations already declare readOnly, idempotent, non-destructive, closed-world. Description adds valuable context beyond that: it discloses the data volume (thirteen puzzles), fields returned (blurbs, exact ids), and crucially that no answers are included. Doesn't state pagination or formatting, but for a zero-param listing with rich annotations this is strong.

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 clauses, front-loaded with what it lists, then the exclusion (no answers), then sibling routing. Every sentence carries distinct information with zero waste.

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 no-param, read-only listing tool with full annotation coverage and no output schema, the description covers what it returns, what it omits, and how it differs from siblings. An agent has everything needed to select and invoke it correctly.

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?

Zero parameters, so baseline is 4. The description doesn't need to explain params and appropriately doesn't; it instead clarifies the content of the returned list.

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 (List) and resource (today's thirteen puzzles) plus what each entry contains (blurbs, exact daily ids), and explicitly notes what is excluded (No answers). Distinguishes from siblings open_daily and get_rules by describing the non-opening, non-explaining listing behavior.

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?

Explicitly routes usage: use open_daily to play one or the hub, and get_rules to explain a game without opening it. This gives clear when-to-use vs alternatives, with the list_dailies role (discovery) implied by contrast.

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