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

Beyond readOnly/idempotent annotations, it discloses many behavioral traits: 24-hour cached-copy serving, live Steam fallback, keyless shared daily cap versus private key quota, found=false for private or empty inventories, stale=true when Steam was unreachable, and value_history being re-priced in USD dollars rather than cents.

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 front-loaded with the core purpose, then moves into output details and operational behavior. It is dense and long, but most of the length is justified because there is no output schema and the return shape is complex.

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 no output schema, the description carries the burden of explaining returns and does so thoroughly: priced skins with quantity/price/value, filter-like attributes, total_value, item_count, distinct_skins, categories with share percentages, owner info, value_history semantics, found, and stale. It also covers ID format, public-inventory requirement, caching, and auth quota.

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?

The single parameter has 100% schema description coverage, so the schema already covers the SteamID64 format. The description reinforces the 17-digit requirement and names resolve_steam_profile as a helper, but adds limited semantic detail beyond what the schema provides.

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 states a specific verb and resource: value a Steam account's Rust skins, and immediately lists the rich output shape (priced skins, totals, categories, owner, history). It does not explicitly differentiate itself from close siblings such as get_inventory_valuation, get_inventory_snapshot, or get_inventory_value_history, so it stops short of a 5.

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 clearly gives prerequisites: a 17-digit SteamID64, a public inventory, and use of resolve_steam_profile for URLs or vanity names. It also explains caching behavior and API-key quota handling, but never states when an agent should choose this tool over the inventory-related siblings.

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