hl_place_order

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

With no annotations, the description carries the full burden and does well: it discloses the owner-set constraint regime (per-order and daily notional caps, max leverage, allowlist) and the exact failure semantics (403 + cap_* code, no retry). It omits auth requirements and what a successful response contains, keeping it short of 5.

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, all load-bearing: the core action, the constraint/failure behavior, and the market-order workaround. Front-loaded with no filler.

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 write tool with no annotations and no output schema, it covers the critical traps (limits, error code, no-retry, no market orders). The main remaining gap is the success response shape and any auth prerequisite, which the agent would have to discover empirically.

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 all six parameters including the tif enum and reduceOnly are already documented inline. The description adds only the conceptual point that an aggressive px crosses the spread, which is marginal beyond the schema baseline of 3.

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 a specific verb+resource ('Place a limit order on Hyperliquid') and implicitly distinguishes itself from siblings like hl_cancel_order and hl_swap. An agent immediately knows this is the order-entry tool.

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?

Gives strong operational guidance: exceeding owner limits returns 403 with a cap_* code and must not be retried, and it explains how to emulate a market order since none exists. It does not explicitly route to sibling tools, but the when/when-not for this tool is clear.

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