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

Annotations declare readOnlyHint=true, and the description is consistent with that: it only produces a message to sign rather than mutating anything. Beyond the annotations it adds genuinely useful context — that the trading key is required, and that the resulting cancel is off-chain, instant, and free — though it does not say the order remains open until the signed message is submitted.

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?

One sentence with no filler, and the key fact (it returns a signing message, not a cancellation) is front-loaded. The phrasing 'the message to personal_sign with the trading key' is slightly compressed but still readable.

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 should fully explain what comes back and what to do with it. It states a message is returned, but leaves the agent to guess the exact shape and the required hand-off to submit_cancel, which is a meaningful gap in a two-step flow.

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 0% for the single required parameter, so the description carries the full burden of explaining orderHash. It says nothing about the parameter at all — not that it identifies the specific open order being cancelled, nor any format expectations beyond the regex pattern in the schema.

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 gives a concrete verb and outcome: it returns a message to personal_sign with the trading key in order to cancel one open order. It is clear that this is the signing-prep half of a cancel flow, though it never names submit_cancel as the follow-up step, so the split from its sibling must be inferred.

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?

'Off-chain (instant, free)' hints at when this path is preferred, but there is no explicit statement of when to call it versus submit_cancel or what must happen between the two calls. Usage is implied rather than prescribed.

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