SimpleFunctions

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

No annotations provided, so description carries full burden. Discloses 'Read-only' safety profile and 'billed per Databento usage' cost structure. Could improve by mentioning rate limits or error behavior when symbols are invalid, but covers key operational constraints.

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?

Three sentences, zero waste. Front-loaded with action verb. First sentence defines scope, second discloses operational traits, third provides selection guidance. Every clause earns its place.

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 100% schema coverage and 6 parameters, description successfully covers purpose, cost, safety, and sibling differentiation. Lacks output format description (expected given no output schema), but mentions return data types (OHLCV/trades/quotes). Sufficient 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?

Schema has 100% coverage (baseline 3). Description adds categorical context for symbols parameter by distinguishing 'traditional instruments' vs prediction markets, reinforcing the venue constraints implied by the dataset parameter. Mentions data types (OHLCV/trades/quotes) that map to schema parameter values.

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?

Opens with specific verb 'Fetch' targeting 'market data from Databento' and explicitly lists asset classes (CME futures, US equities, crypto). Critically distinguishes scope from siblings by contrasting 'traditional instruments' with prediction markets.

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?

Explicitly states when to use ('Use for OHLCV / trades / quotes on traditional instruments') and names exact alternatives for other use cases ('use get_markets or search_markets for prediction-market contracts instead'). Also notes cost model implications.

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