query_databento

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

Discloses read-only nature and billing per usage. No annotations exist, so description carries full burden. Could mention data ordering or error handling but still provides key behavioral context.

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 highly informative sentences with no filler. Front-loaded purpose, followed by usage guidance. Every sentence 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?

Covers purpose, usage, parameters, and billing. No output schema, so return format is omitted, but for a data-fetching tool with good parameter descriptions, it's nearly complete.

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%, baseline 3. Description adds extra context: continuous-contract suffix explanation, dataset default, and symbol examples, improving parameter understanding beyond schema.

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 the tool fetches real-time and historical market data from Databento, specifying the resource and verb. It distinguishes from siblings by directing prediction-market queries to get_markets or search_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 tells when to use this tool (for traditional instruments OHLCV/trades/quotes) and when to use alternatives (prediction markets), with clear exclusions.

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