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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description goes beyond them by disclosing what the response contains (condition field, marketplace labeling fields) and how to surface shipping info. It does not cover failure behavior for a bad id/URL, which keeps it below a 5.

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?

Front-loaded with the core action and lookup keys, then a parenthetical field list and a doc link. The field inventory is dense but relevant to a tool with no output schema; nothing is wasted, though the listing could be trimmed.

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 partially compensates by naming response fields (condition, is_marketplace, marketplace, ships_from, etc.), which is genuinely useful. It still omits the url-vs-deal_id contract and any error/not-found behavior, leaving gaps for a lookup tool with zero required parameters.

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 only 33% (just the market enum), so the description has to carry the rest; it does clarify that url is a moneydeals.com deal URL and deal_id is the deal identifier. However, with 0 required params it never says whether url or deal_id should be used, whether they are mutually exclusive, or which wins if both are supplied.

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 ('Get one deal by its id or moneydeals.com deal URL'), and the singular 'one deal' plus the identified lookup key distinguishes it from siblings like search_deals and get_coupons. An agent can select this 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?

It tells the agent how to identify a deal (id or URL) and even how to present results ('mention ships_from and delivery time'), but never states when to prefer this over search_deals or what to do when the deal is unknown/invalid. Usage is implied rather than routed.

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