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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuinely useful context beyond that: it draws from indexed history and explains the key advantage over Hyperliquid's native userFills endpoints (which truncate at 10,000 fills), giving the agent a reason to prefer this tool. It doesn't mention pagination semantics or latency, but the core behavioral differentiator is disclosed.

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: the first front-loads what is returned, the second justifies the tool with a concrete comparison. No filler, though the returned-field list sits a bit dense and could be trimmed since an output schema exists.

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?

With annotations covering safety, a full parameter schema, and an output schema, the description only needs to convey scope and the indexing rationale, which it does. A mention of ordering (chronological vs reverse) would round it out fully.

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 all three parameters are already documented, including limit range and market naming formats. The description only implies the market filter is optional and that address scopes to one wallet, adding minimal value beyond the schema. 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+resource (retrieve every fill for one wallet), names the returned fields (price, size, side, fee, realized PnL) and the optional market scope. Distinguishes it from related siblings like get_recent_trades and get_user_ledger by tying it to a single wallet's fill history.

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?

Implicit guidance: use this when you need a wallet's fill history beyond the API's 10,000-fill cap, and the optional market parameter hints at filtered lookups. But it never states when NOT to use it or names an alternative sibling (e.g. get_user_ledger for non-fill ledger events, get_recent_trades for market-wide trades).

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