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

Annotations already establish readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds only the filtering behavior ('narrows to instruments covering a given construct') and the term 'rows', but nothing about pagination, ordering, ownership scope, or response size.

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 with the action front-loaded and no wasted words. The filter clarification earns its place, though several parameters are undocumented—this is under-specification rather than verbosity.

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 5-parameter, 0%-schema-coverage list tool with no required parameters, the description covers only one filter; limit/offset and license/owned semantics are missing. The presence of an output schema reduces the need to describe return shape, but the calling semantics remain incomplete.

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%, so the description needed to clarify the parameters; it only explains construct_id. The remaining four parameters (limit, offset, owned, license) are left entirely to schema names, and their semantics are absent.

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 uses a specific verb ('List') and resource ('InstrumentCard rows') and adds a meaningful optional filter, so an agent knows what it returns. It doesn't explicitly contrast with sibling search/lookup tools, but the list/search/lookup naming convention plus 'rows' makes its role reasonably clear.

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?

The description implies the main use case: fetch instrument cards, optionally narrowed by construct_id. It gives no guidance about when to prefer this over principia.instruments.search or principia.instruments.lookup, nor any exclusions or preconditions.

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