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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful context beyond that — the records include live settlement marks denominated in dollars and come from a specific endpoint — but says nothing about pagination, result size, or rate limits.

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, front-loaded with the resource and scope, with no filler. Slight redundancy in re-listing the enum values already present in the schema keeps it from a 5.

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?

An output schema exists, so return-value explanation is unnecessary, and one optional enum parameter with an annotation-covered safety profile is a simple surface. The description covers purpose, endpoint and filter; only pagination/scale behavior is unaddressed.

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% and the single enum parameter already documents 'Default active.' The description merely restates the same enum values and default, adding no syntax, format, or behavioral detail beyond the schema. Baseline 3 applies.

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 (List) and resource (Kalshi perpetual tickers and their live settlement marks), plus the source endpoint (GET /perps/markets) and the data's unit (dollars). It is clearly distinguishable from get_perp_mark and get_perp_history by being a listing operation, though it never explicitly names those siblings.

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?

Listing intent is implied by 'List ... tickers', and the status filter values give some operational context, but there is no explicit statement of when to use this versus get_perp_mark or get_perp_history, and no prerequisites or exclusions are mentioned.

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