get_closing_prices

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

Beyond readOnlyHint, description discloses rate limit, return format with sentinel values for missing data, and behavior of filtering/truncation. Adds significant value over annotations.

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?

Front-loaded with purpose, each sentence adds new information (filtering, return structure, sentinel, rate limit). No redundancies or fluff.

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 simple parameters and presence of output schema, description fully explains tool behavior, edge cases, and constraints. No gaps remain.

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%, but description adds context like 'truncates' for limit and 'filters' for instrument_ids, clarifying behavior beyond schema descriptions.

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?

Description clearly states 'Get the latest official closing prices per instrument', specifying the action and resource. It differentiates from sibling tools by focusing on closing prices with optional filtering.

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?

Description explains that the tool returns closing prices for all instruments and then filters/truncates, but does not explicitly state when to use this tool over alternatives like get_candles. Still provides clear context.

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