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

Annotations only provide readOnlyHint and destructiveHint, so the description carries the real burden and delivers: caching (60 s), auth requirement (none), privacy guarantees ('Never an owner wallet or a runner identity'), ranking tiebreak rules, and full field inventory of every returned card. This is rich behavioral context beyond what annotations provide.

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?

Dense but front-loaded: the first sentence establishes identity and routing, then it moves through scope, auth, fields, and parameters in a logical order. Every sentence carries operational information; no filler.

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?

Complete for a read-only list tool with no output schema: the description enumerates every card field, the ranking behavior, the cache window, the privacy boundary, the parameter semantics, and the sibling relationship, so an agent has everything needed to call 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?

Schema coverage is 100%, so the baseline is 3, but the description adds genuine meaning: it explains what 'top' means (most used — uses, then distinct users, then last active), the meaning of each kind value, and the limit range. It explains the semantics of the enums, not just their names.

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 ('THE FRONT CARDS (GET /api/front)') and clearly positions itself against the sibling market_search ('for the store itself... use market_search'). The agent can distinguish it from market_search without opening either 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?

Explicitly names the alternative ('for the store itself (aisles, departments, the whole open registry) use market_search') and states when to use each. Also documents 'Public, no auth' and 'Cached 60 s', giving concrete usage context.

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