Market movers

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

Annotations already declare readOnlyHint/idempotentHint, so safety is covered. The description adds genuine domain context the annotations can't: only instruments that traded are listed, limit_up/limit_down flags mark a price stuck at its daily limit, and prices are denominated in Rial. It doesn't mention ordering/page behavior beyond limit, but the added semantics are substantive.

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?

Four short sentences, front-loaded with the core purpose, followed by the traded-only constraint, the limit flag semantics, currency units, and the sibling hand-off. No filler or repetition of schema fields.

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 supplies exactly the row-level semantics an agent needs (traded-only listing, limit_up/limit_down flags, Rial pricing) and tells it how to drill down via siblings. A note on row ordering/pagination or the columns returned would make it fully complete.

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 description coverage is 100%, so the schema already defines limit, market enum values, and sort_by semantics. The description's phrase 'ranked by gain, loss, volume, value or trade count' restates the sort_by enum without adding format or constraint detail, so 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?

States a specific verb and resource ('Top traded instruments of a market today') plus the ranking dimensions, so the agent knows this is a ranked leaderboard endpoint. Sibling tools like ts_indices and ts_price_history cover different resources, and the description's 'top traded instruments of a market' scope is clearly distinct from a single-symbol quote lookup.

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 the discovery use case and explicitly routes follow-up work: 'Pass a row's `symbol` to ts_get_quote or ts_order_book.' It doesn't state when NOT to use this (e.g. use ts_price_history for a time series), but the context is clear enough for correct selection.

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