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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context by enumerating the returned fields and the three sort orders, but says nothing about data freshness/vintage or update cadence for fortnightly flow data.

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?

Three tight sentences, front-loaded with what the tool returns before the interpretive note. Minor redundancy between the field enumeration and the sort-order sentence, but 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?

With no parameters and no output schema, the description carries the return-value burden and does so by listing the four payload elements and the three sort orders. An agent could call this correctly; only data-freshness semantics are missing.

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?

The tool takes zero parameters, so the baseline of 4 applies. The schema is an empty object and there is nothing parameter-wise for the description to clarify or omit.

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 resource ('FPI sector-wise investment data') with concrete output contents (AUM share per sector, fortnight change, 1Y flow, sparkline). The 'sector-wise' scope naturally distinguishes it from the sibling flow tools (get_fii_dii_flows, get_fii_dii_detail), though it never names those alternatives directly.

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 closing sentence ('Useful for understanding which sectors foreign investors are buying/selling') implies a use case but gives no explicit when-to-use trigger, no when-not-to-use condition, and no routing to the sibling FII/DII tools an agent might confuse it with.

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