get_derivatives_bars_daily_options_225

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

The annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, so the safety profile is well covered. The description adds useful behavioral context by explaining this is the 'simplified' variant and listing supported plans (Standard/Premium). It does not contradict any annotation, and the plan accessibility note is valuable beyond what annotations provide.

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 compact, front-loaded with the core purpose, and includes plan info, an alternative reference, and an args list. The only minor issue is the ambiguous phrase 'Standard+' followed by 'Standard plan accessible', which creates slight redundancy and could confuse readers about the actual plan tier.

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?

This is a simple single-parameter read-only tool with an output schema available, so the description does not need to explain return values. It covers purpose, target instrument, plan accessibility, alternative usage, and the date parameter format. The 'Standard+' ambiguity is a minor gap, but overall the context is sufficient for correct invocation.

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 input schema has zero description coverage for the single 'date' parameter, but the description compensates by specifying the accepted date formats (YYYYMMDD or YYYY-MM-DD) and marking it required. This gives the agent clear syntax guidance that is not present in the schema alone.

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 clearly identifies the tool as providing daily Nikkei 225 options OHLC bars, including the Japanese term 日経225オプション for disambiguation. It also distinguishes itself from the sibling get_derivatives_bars_daily_options by noting this is the simplified version for Nikkei 225 only, while the sibling covers TOPIX options and IV.

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 explicitly states the intended use: 'Use for 日経225オプション, オプション日足 (simplified)' and notes it is accessible on the Standard plan. It also directs users needing full options data including TOPIX options and IV to get_derivatives_bars_daily_options (Premium only), providing a clear alternative and when-not-to-use guidance.

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