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

Annotations already cover the safety profile (readOnlyHint, openWorldHint, destructiveHint=false), but the description goes further by disclosing a real data-source anomaly: the spec omits /lol even though LoL routes work, so game=lol returns a caveat instead of an empty list. It also states parallel-safety and upstream cost, which agents need for batching decisions; only pagination/truncation behavior at the limit boundary is left unaddressed.

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?

Front-loaded with the one-line definition, then clearly separated usage, exclusion, note, and metadata blocks, ending with an example. Nearly every line earns its place, though the 'Prefer curated tools' sentence and the 'Do not use when' bullet overlap slightly in conveying the same routing advice.

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 three-parameter, read-only index tool with full schema coverage, an output schema, and complete annotations, nothing an agent needs in order to call it correctly is missing. The description covers purpose, routing, a data-source quirk, cost, and a concrete invocation example.

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 coverage is 100%, so the baseline is 3, and the description earns above that by supplying a worked example ({ "game": "ufc", "q": "rankings" }) and a caveat specific to the game filter. It also notes fortnite is accepted by game even though the schema enum lists only seven values — a genuine clarification the schema does not contain, though it is left ambiguous whether fortnite is a valid enum input.

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 opening sentence names a specific verb and resource — an index of raw REST routes drawn from the live OpenAPI spec — and enumerates the fields returned (method, path, summary, tag). It is immediately distinguishable from siblings: list_capabilities covers curated capabilities and call_api executes, while this is explicitly the 'escape hatch' index.

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?

Provides three concrete when-to-use bullets (finding long-tail paths for call_api, checking endpoint existence, mapping raw data behind a curated tool) plus an explicit 'Do not use when' rule that routes the agent to list_capabilities. The preference ordering between curated tools and this index is stated outright rather than implied.

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