index_contributors

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so safety is fully covered. The description does add one genuinely useful behavioral detail — results are expressed in index points and include both upward and downward contributors — but it says nothing about ordering, how many are returned by default, or the index scope, and no output schema exists to fill that gap.

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?

One front-loaded sentence that states the semantics first and appends a Persian synonym, which plausibly aids matching for a Persian-language data source. No filler, though the parenthetical duplicates the concept rather than extending it.

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 single-parameter, no-output-schema tool this is close to adequate, but an agent still cannot tell the sort order, whether positive and negative contributors are interleaved or split, or what the limit applies to. Those gaps are small but real for a tool whose whole value is a ranked list.

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 0%, and the description never mentions the single 'limit' parameter, so nothing in prose explains whether it caps contributors per direction or overall. The schema does carry a default of 15 and a max of 60 structurally, which keeps this from being a 1, but the description adds no compensating meaning.

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 names a specific output resource: stocks that move the total index the most, measured in index points. That is concrete enough to distinguish it in substance from a generic movers list, though it never explicitly contrasts itself with the sibling top_movers, so the agent has to infer the difference.

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?

There is no when-to-use guidance, no mention of prerequisites, and no naming of an alternative such as top_movers or market_overview when the agent wants plain price change rather than index-point contribution. The agent must guess the selection condition from the tool name alone.

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