market_overview

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

The description accurately describes the read-only nature (returns data, no mutation) which aligns with the readOnlyHint annotation. It details the returned components, ensuring full transparency.

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?

Two sentences: first sentence defines the tool's purpose, second sentence elaborates on components. No redundant information, front-loaded and efficient.

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?

Given zero parameters and an output schema, the description is complete. It covers all output elements and the overall purpose, providing sufficient context 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?

With no parameters, the description adds value by explaining the output structure. Baseline for zero parameters is 4, and the description fully compensates by listing all data fields.

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 specifies exactly what the tool returns: major market indices (S&P 500, NASDAQ, DOW, Russell 2000), VIX, top movers, and market sentiment. This clearly distinguishes it from siblings like stock_quote or compare_assets.

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 implies it's for a broad market snapshot, but does not explicitly state when to use it (e.g., for a high-level overview) or when not to (e.g., for detailed individual stock data). No comparison to alternatives is provided, leaving the agent to infer usage context.

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