show_benchmark

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

No annotations provided, so the description must disclose behavior. It explains the dual-mode operation: uses daily snapshot history when available, otherwise falls back to cost-basis vs current value. This is transparent about how the tool works under different data conditions.

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, no fluff. The first sentence clearly states the purpose, the second explains the behavior and fallback. Every word contributes.

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 tool with no output schema, the description covers purpose, defaults, and behavior. It lacks explicit mention of return format (e.g., chart, table) but is otherwise complete for selection and use.

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% with descriptions for all three parameters. The description adds context beyond schema: defaults for benchmarks and date ranges based on data availability, and the fallback behavior. This provides useful meaning.

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?

Clearly states the verb 'compare' and resource 'portfolio return against benchmark indices' with defaults (SPY and QQQ). Differentiates from sibling 'show_' tools by specifying benchmark comparison.

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?

Explains when to use (compare portfolio return) and provides context on default benchmarks and fallback behavior when snapshots are missing. Lacks explicit exclusions or alternatives among siblings.

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