Get a quote

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

The description discloses crucial behavior beyond the annotations: 'On the replay source it is the last stored bar's open time rather than the current clock, so the answer is reproducible and is NOT a live market price.' It also details error handling for unknown symbols. This adds significant context for an agent deciding whether to trust the result as live.

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 two short sentences plus a crucial behavioral note. Every sentence adds value, and the key action ('Return...') is front-loaded. No redundant or vague language. It is concise without omitting necessary information.

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 the tool's simplicity (one required parameter, no nested types) and the existence of an output schema (not shown but indicated in context signals), the description adequately covers the return value, time source, error behavior, and a pointer to list_symbols. It is complete for an agent to use correctly.

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 100% coverage for its single parameter 'symbol', with description 'Instrument name exactly as list_symbols spells it.' The tool description does not add new semantic meaning; it only repeats the schema's point about exact spelling. Baseline 3 is appropriate when schema already fully documents the parameter.

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 'Return the latest bid, ask and spread in points for one instrument.' The verb 'return' and resource 'quote for one instrument' are specific. It implicitly distinguishes from sibling tools like get_bars (historical bars) and list_symbols (listing symbols).

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 provides explicit guidance: 'An unknown or unavailable symbol returns a tool error naming the symbol; call list_symbols if unsure.' This tells the agent when to use list_symbols instead. It does not explicitly state when not to use this tool (e.g., for historical prices use get_bars), but the sibling context and the mention of 'latest' imply the appropriate use case.

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