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

With no annotations, the description carries the behavioral burden. It provides some transparency by noting the 'active' filter and pagination via next_cursor, but it does not disclose output shape, ordering, auth requirements, or what 'active' means. This is reasonable for a read-only catalog query but not complete.

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?

The description is two sentences with no filler: the first states purpose and scope, the second packs parameter guidance. It is front-loaded and easy to scan.

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 five-parameter tool with no annotations and no output schema, the description gives enough to invoke basic paginated discovery, but it omits response contents, default limit behavior, and any access context. These omissions leave a moderate gap.

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 only 40%, so the description must compensate. It clarifies the roles of search, exchange/asset_class, and cursor, but limit is left undocumented and the filter descriptions are mostly directional rather than substantive. Partial compensation only.

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 opens with 'Discover active instruments,' giving a specific verb and resource and adding the 'active' scope. It is clearly distinguishable from the sibling tools, none of which deal with instrument catalog listing.

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?

It gives clear context for when to call the tool (to discover active instruments) and how to refine with search, exchange, asset_class, and cursor. There are no instrument-catalog siblings to exclude, so explicit when-not/alternative guidance is not required.

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