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

The annotations already declare read-only, idempotent, and non-destructive behavior. The description adds valuable context beyond that: the score is a trust-weighted function of settled transactions, derived from ComOS-signed counters, and is presented as a fact rather than a verdict. No contradiction with annotations.

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 information-dense and well-organized, covering definition, usage modes, catalog relationships, return shapes, and an example. It is slightly longer than strictly necessary, with a few phrases (like the CO 200 detail) that could be trimmed, but overall each section earns its place.

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 compensates by detailing exact return shapes for both the default/leaderboard mode and the tenant_id mode, including field names, nullability, and the filter field. It also explains the relationship to catalog tools and the scoring rationale, making it comprehensive enough for confident tool selection.

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 input schema covers all three parameters (limit, platform, tenant_id) with complete descriptions, so the schema does the heavy lifting. The description only reiterates the purpose of platform and tenant_id and mentions limit in the return format; it adds little beyond schema coverage.

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 clearly defines the tool as a live arena ranking agent-run businesses by settlement-signed reputation, with distinct operations for the full board, platform filtering, and single-tenant lookup. It also distinguishes itself from catalog siblings by explaining the catalog-to-arena relationship.

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?

Explicit usage instructions are provided: omit args for the top of the board, use platform= to filter by vendor type, and tenant_id= for one business's rank. It also names companion tools (federation_catalog_agents/platforms) and clarifies that the catalog is for entry while the arena is for ranking.

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