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

readOnlyHint=true already tells the agent this is a safe read. The description adds one genuinely useful behavioral note: the trade-up map is 'catalog contract math, not scanner output,' which warns the agent not to treat it as live market data. Nothing is said about pagination limits, response size, or cost of including the map.

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?

Three sentences, zero filler, with the primary list/single behaviour front-loaded before the optional map. The last sentence is a compact caveat that earns its place, though 'catalog contract math' is slightly jargon-heavy.

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?

Seven parameters with no output schema and only a readOnly annotation; the description covers the two modes and what the trade-up map contains but says nothing about the paged list response, sorting behaviour, or what a collection payload looks like. Adequate for a browsing tool but with visible gaps.

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 every parameter is already documented and the baseline is 3. The description paraphrases the map contents and the list-vs-slug behaviour that the schema already states, adding little new parameter meaning beyond the provenance caveat.

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 and resource ('List Counter-Strike 2 collections') and cleanly separates two operating modes: the list and the single collection with contents. It is distinguishable from browse_cases and get_skin_detail, though it never explicitly names a sibling to route against.

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 dual-mode structure ('or get one collection with its contents') implies when each mode applies, and the trade-up map is framed as optional. However, there is no explicit when-to-use/when-not guidance and no alternatives named among the many siblings (search_cosmetics, browse_cases, get_tradeup_preview).

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