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

The description adds significant behavioral context beyond annotations: it clarifies the index is 'fixed-basket same-card index (never vibes)', states it's 'not investment advice', and lists specific output components (phase read, peak/drawdown, sale counts, calendar). Annotations only declare readOnlyHint and non-destructive, so description bears full burden and does so well.

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 a single, well-structured sentence that front-loads the core purpose and packs all key details without extraneous words. Each clause adds value.

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?

Given the tool has only one optional parameter and an output schema exists, the description covers all necessary behavioral and output context. It lists the key outputs (phase read, index, peak/drawdown, sale counts, calendar) and notes 'not investment advice', which is complete for an agent to understand and invoke 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% for the single parameter (market enum with description). The description mentions 'per language track (all / en / ja)' but omits zh-cn from the schema. This adds no new meaning beyond the schema; baseline 3 applies.

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 clearly states the tool provides a market cycle phase read, index values, peak/drawdown numbers, sale counts, and an event calendar. It specifies the scope (graded-Pokémon market per language track) and distinguishes from sibling tools like market_movers and market_volume_leaders.

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?

The description implies use for obtaining a high-level market overview with specific metrics, but doesn't provide explicit guidance on when to use this tool versus alternatives like market_movers or market_volume_leaders. No when-not-to-use guidance.

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