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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description stays consistent while adding real substance: per-row return fields (ticker, score, band and its meaning, direction, move, driving input), plus universe-level band distribution and band-change counts at the last recompute. The clarification that it ranks readings rather than flagging companies to avoid is behavioral context found nowhere in the structured fields.

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 dense sentences that front-load the ranking scope, followed by returns, use cases, sibling routing and a caveat — well ordered with no filler. Slight deduction for restating 'Read-only', which the annotations already establish, and for the very long mechanism parenthetical.

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 nine optional parameters and no output schema, the description compensates by enumerating the returned row fields and the aggregate payload. Filter dimensions, mechanism semantics, the includeSlices behavior and the drill-down path are all covered, so an agent could call this correctly without further inference.

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 78%, so the schema carries most parameter documentation. The description still adds useful framing — the six dial names grouped as filterable 'dial coverage', the band/sector/country filter set, and a concrete demonstration of includeSlices ('how risky is tech vs utilities') — though it does not explain limit/offset or sortBy beyond what the schema already states.

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 (rank), a specific resource (Bullrun's ~9,000-company scored universe) and the ranking basis (composite risk or one of six mechanism dials). It distinguishes itself from get_company_risk by explicitly routing row-level drill-down there, so an agent can separate it from siblings like get_risk_movers and screen_stocks.

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?

Gives four concrete query shapes ('which large caps have stretched leverage', 'most concentrated supply chains in semiconductors', 'calmest German industrials', 'how risky is tech vs utilities' with includeSlices) and names the alternative tool for follow-up. It also adds a negative guideline — 'A ranking of readings, not of companies to avoid' — which prevents misuse of the output.

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