get_market_briefing

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

Annotations already indicate read-only and idempotent, but the description adds valuable context: 'cache-only, no API call' and plan restrictions (e.g., sector_short_ratios requires Standard+). It also discloses null behavior when caches are absent, which goes beyond the safety profile.

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?

Although lengthy, the description is highly structured with clear sections: purpose, usage, supports, returns, and args. Every sentence adds actionable information, and the essential purpose is front-loaded. No fluff or repetition.

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?

The description covers all parameters, return fields, plan limitations, and null behavior. With an output schema present, it doesn't need to detail every field but still provides a useful summary. It also explains when to use the tool, making it complete for an agent.

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 0%, so the description must document parameters. It does this thoroughly: 'date' with format examples, 'sector_type' with allowed values and default, and 'n' with range and default. This fully compensates for the bare schema.

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 states the tool's purpose as a daily market briefing covering ADR, sector ranking, top movers, turnover, and screener highlights. It uses a specific verb-resource combination and explicitly differentiates from sibling tools by naming get_sector_briefing and get_stock_briefing as alternatives for different use cases.

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?

Explicit usage guidance is provided: 'Use for 相場ブリーフィング, 市場概況, 今日の相場, daily briefing, market summary.' It also gives clear exclusions and alternatives: 'For sector valuation (PER/PBR) use get_sector_briefing instead. For single-stock detail use get_stock_briefing instead.'

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