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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds the return payload (status, parameters, fills) and the status lifecycle values, which implicitly explains the non-idempotent annotation (status evolves). It stops short of describing freshness or rate limits, but adds real value beyond the annotations.

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, zero filler, and the core purpose leads before the sibling routing. Every clause earns its place by either defining the return or preventing a wrong-tool call.

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 no output schema, the description must carry the return contract, and it does: status with its enum, parameters, and fills. Combined with the routing guidance, nothing an agent needs to call this correctly is missing.

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?

There is one parameter and schema coverage is 100% – the schema already spells out 'EIP-712 order hash (0x-hex, 32 bytes)'. The description only says 'by hash' and adds no format, casing, or lookup semantics beyond that, so it neither helps nor hurts relative to the baseline.

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 ('One Epsilon order by hash') and enumerates what comes back: status, parameters, and fills. The status enum values (pending/active/filled/cancelled/expired) pin down the resource precisely, and the description explicitly distinguishes itself from list_orders and get_orderbook.

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 explicit routing: use list_orders first to find an order by wallet, and use get_orderbook for a pair's resting orders. Both alternatives come with the condition that selects them, so an agent knows exactly when this tool is the right call.

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