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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is fully covered without the description. The description adds nothing beyond that: it does not say whether all expirations are returned in one payload, whether results are large/need paging, or how the optional expiration narrowing behaves. No contradiction, but no added behavioral value.

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?

A single short sentence with zero filler and the key subject front-loaded. It is appropriately terse for a two-parameter list tool, though the brevity comes at the cost of the missing guidance noted elsewhere.

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 full schema coverage, complete annotations and no output schema, the description is technically sufficient to invoke the tool correctly. It is thin for a tool whose whole purpose is discovery among many near-named siblings, but nothing critical to the call itself 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?

Schema description coverage is 100%, so both parameters are already documented (underlying format example BTC_USDT, expiration as a Unix timestamp). The description only restates that an underlying is the subject and says nothing about the optional expiration filter. Baseline 3 applies when the schema carries the load.

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 specific verb and resource ("List all options contracts") scoped to an underlying, which is unambiguous on its own. However, it never distinguishes itself from close siblings like cex_options_get_options_contract (single contract) or cex_options_list_options_expirations, so an agent must infer the boundary from the tool name 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?

There is no explicit when-to-use statement, no prerequisite, and no named alternative. The phrase "for an underlying" implies it is the per-underlying enumeration step, but nothing tells the agent when to prefer this over get_options_contract or how it relates to the expirations listing.

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