Index Level History

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

Annotations already mark this as read-only, idempotent, and non-destructive. The description adds valuable behavioral context beyond that: it returns OHLC plus valuation metrics, is official NSE index data, covers ~140 indices, and explicitly states that intraday is not served and that bars are daily up to 1y and weekly for 2y/max.

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 front-loaded with the core action and data content, then gives usage examples, sibling differentiation, and the multi-index alternative. Every sentence adds useful information; there is no filler or tautology.

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 two-parameter read-only tool, this is complete: annotations cover the safety profile, schema covers parameter semantics, and the description covers output composition, supported index categories, return-bar cadence, and intraday exclusion. No output schema exists, but the description sufficiently defines what the caller will receive.

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%, so the baseline is 3. The description adds meaning by clarifying that exactly one index is addressed at a time, providing real index-name examples, and noting the broader universe of '~140 more'. This enriches the parameter understanding even though the schema already documents interval and index_name.

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 uses a specific verb and resource: 'Get the historical LEVEL series (OHLC + PE/PB/dividend yield) for a single NSE INDEX'. It lists concrete examples, names the counterpart tool get_price_history, and contrasts with get_index_performance, so an agent can distinguish it from its siblings immediately.

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?

It provides explicit when-to-use examples such as 'what did Nifty IT close at on <date>' and 'India VIX over the last month'. It also states exclusions: individual stocks should use get_price_history, and multiple-index comparison should use get_index_performance.

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