Market movers

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

Annotations already cover safety (readOnly, idempotent, openWorld), but the description adds two things they don't: a per-call cost of 5 units and an 'ultra plan or higher' entitlement requirement. That materially affects invocation decisions. It loses a point for restating the cost twice and saying nothing about pagination or what a full response contains.

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 purpose, which is good, but the cost is stated twice ('Costs 5 units per call' and 'Cost: 5 units.'), so the last sentence is pure waste. The three sentences are short but not all earn their place.

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 six-parameter tool with no output schema, the description should say more about the shape of results (e.g. that limit applies per direction, which direction defaults to). The entitlement and cost details are covered, but return semantics and the meaning of set_id/direction are left entirely to the schema.

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 67%, so several parameters are already documented. The description only obliquely touches parameters via 'over a window' and 'gainers/losers', but adds no syntax or semantics for set_id (undocumented in the schema) or direction. Baseline 3 fits a description that leaves the schema to do the work.

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-like action and resource: biggest price gainers/losers for a game over a window. It's clearly distinct from siblings like flipzi_get_price or flipzi_get_history, which fetch individual or historical prices rather than ranked movement. It stops short of naming an alternative to differentiate itself, but the resource is unambiguous.

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?

Provides a cost-driven usage constraint ('use sparingly') and a plan prerequisite, which is genuine guidance. However, it never says when to prefer this over flipzi_get_price or flipzi_get_history, nor when a movers query is the wrong tool. Usage is implied rather than routable.

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