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

With no annotations, the description carries the full burden. It discloses that the data is 'live' and sourced from OKX, and that the call targets one asset at a time. However, it does not mention rate limits, potential error conditions (e.g., invalid symbol), or whether the call is safe/read-only. For a simple fetch tool this is adequate but not comprehensive.

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 sentences, both purposeful. The first defines the tool's exact scope and fields, the second gives direct usage guidance. No filler or repetition of schema 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?

For a tool with one parameter and no output schema, the description covers the return value contents, the data source, and use cases. It would benefit from a note on response format or behavior for unsupported symbols, but given the simplicity, it is 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 description coverage is 100% and the schema already explains the symbol parameter with examples. The description adds context that it is a single asset and ties it to the derivative data, but does not add materially beyond the schema, so the baseline 3 applies.

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 names a specific verb ('get'), a specific resource ('perpetual-futures derivatives for one crypto asset from OKX'), and enumerates the exact data fields returned (funding rate, open interest, long-account %, last price). This clearly differentiates it from siblings like get_market_overview or get_market_state, which sound broader in scope.

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 when-to-use guidance: 'Use when the user asks about funding, open interest, positioning, or the perp price of a specific coin.' It does not, however, mention when not to use it or name alternative sibling tools, so it stops short of full exclusionary guidance.

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