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

Annotations only declare read-only/idempotent/closed-world; the description goes well beyond that by enumerating the exact fields returned (stage, window, heat, timing verdict, feasibility level, barrier thresholds, one-sentence reason) and by flagging that these are documented heuristics, not scores or forecasts. It also discloses data provenance (asOf in UTC, source, letter grade with the A/B/C/D thresholds and estimate-range meaning) and a revenue-estimate caveat — precisely the caveats an agent would otherwise get wrong.

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?

It is front-loaded with the strongest hook and stays information-dense with no filler sentences. It is, however, a long run-on chain of parentheticals, and the embedded grade-definition block sits awkwardly inline next to a pointer to wieldr://methodology where it arguably belongs.

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 five-parameter, read-only ranking tool with an output schema, this covers what an agent needs to call it correctly and to interpret grades and estimate ranges honestly, and it names the natural next step. The remaining gap is sibling positioning — nothing tells the agent why to choose this over list_niches or analyze_niche for a given question.

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 the baseline is 3. The description adds only modest meaning beyond the schema: it clarifies that ranked niches exist on Roblox and Fortnite (reinforcing the platform enum) and that team size and horizon drive ranking, but the more useful nuance (e.g. that horizon only moves closing/crowded niches) already lives in the schema text.

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 clause states a specific verb and resource ("ranks every ranked niche (Roblox and Fortnite)") plus the two ranking axes (team size, build horizon), which is far more than a restatement of the name. It implicitly separates itself from a plain listing like list_niches, but never names a sibling it is *not*, so disambiguation from analyze_niche relies on inference.

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 framing question ("What to build, with what odds, and whether it is too late") gives a clear decision context, and it prescribes a concrete follow-up ("Then call get_gap_analysis on a key"). It does not state when to prefer list_niches or analyze_niche instead, so the routing guidance stops short of explicit alternatives.

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