open_perp_position

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

With no annotations, the description carries the full burden, yet it only restates that it opens a leveraged position and supports market/limit orders (the latter already implied by the isMarket param). It omits high-stakes behavior for a financial mutation: whether cross or isolated margin is used, auth/session requirements, collateral prerequisites, failure/partial-fill behavior, and irreversibility of the action.

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 tight sentences with no filler and the core action front-loaded. It is efficient, though it spends its second sentence on information already covered by the schema's isMarket flag rather than higher-value behavioral context.

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 12-parameter, 7-required financial mutation with no annotations and no output schema, the description is too thin. It leaves auth expectations, margin mode, prerequisite state, and the risk/reversibility profile unaddressed, so an agent lacks what it needs to invoke this safely.

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%, so every parameter (including leverage range, reduceOnly, tpPrice/slPrice, isMarket) is already documented in the schema. The description merely echoes 'leverage, TP/SL' and market/limit without adding syntax, defaults, or edge-case meaning, 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?

States a specific verb and resource ('Open a perpetual futures position on HyperLiquid') and names the key capabilities (leverage, TP/SL, market/limit). However, it does not distinguish itself from the very similar sibling 'place_perp_order', nor from 'execute_cross_perp'/'execute_isolated_perp', so an agent cannot tell which opener to pick from the description alone.

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?

No when-to-use guidance and no alternatives are named, despite multiple overlapping siblings (place_perp_order, execute_cross_perp, execute_isolated_perp, limit_buy). Nothing tells the agent when this tool is preferable to those or what prerequisites (e.g. deposited collateral, enabled trading) must hold.

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