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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds useful behavioral context beyond that: it explains the row shape, the split ratio semantics, and the request-unit cost. It does not discuss pagination or optional date-window defaults, so it falls short of full transparency.

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 tightly packed sentences, front-loaded with the core purpose, then output semantics, then the alternative and cost. No sentence is redundant.

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 simple read-only endpoint with full schema coverage, an output schema, and annotations, the description is complete enough. It covers purpose, return semantics, alternative routing, and cost without needing to restate schema or output schema details.

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%, so the schema already documents 'symbolExchange', 'from', and 'to'. The description reinforces the 'SYMBOL.EXCHANGE' format for the required parameter, but does not add syntax or constraint details beyond the schema, so baseline 3 is appropriate.

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 states a specific resource ('Split history') and scope ('one SYMBOL.EXCHANGE'), and explicitly distinguishes it from the sibling 'events' path for multi-symbol windows. An agent can identify the tool's precise purpose without opening the schema.

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?

It gives explicit routing guidance: use this for one symbol's split history, and use 'events with view=splits' for splits across many symbols in a date window. The cost note also helps invocation planning.

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