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

Annotations already declare read-only, idempotent, non-destructive behavior, so the description correctly focuses on dataset-specific traits: the 50-record ceiling, the October 3, 2026 history boundary, and per-dataset coverage variance. It omits any mention of authentication failure behavior or what happens when the requested day predates the coverage window, which are the remaining real risks for a caller.

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?

Three short sentences with zero padding; the record cap and history boundary are front-loaded before the pointer to days_available. Every sentence carries distinct information -- constraint, temporal boundary, and routing.

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 and 25% parameter coverage, the description should explain more of the call contract. It never says what a 'wallet observation' contains or what 'top' ranks by, leaving an agent unable to predict results or choose `by` meaningfully -- adequate but with clear gaps for a 4-parameter analytical tool.

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 only 25% -- only `day` is documented in the schema, so the description must carry `n`, `by`, and `api_key`. It repeats the 50-record cap already encoded as the schema maximum but says nothing about the `by` enum values (realizedSol vs solIn), which is the single most consequential parameter choice, nor about ranking direction or the api_key requirement.

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 resource and scope: top daily wallet observations capped at 50, with a history start date. It is clear what the tool returns, but it never distinguishes itself from the close sibling wallet_day, so an agent must guess which of the two to use for per-wallet vs ranked-list queries.

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?

Explicitly routes the agent to days_available to discover the exported UTC day range, which is a concrete when-to-use-an-alternative instruction. It stops short of saying when NOT to use this tool (e.g., for a single wallet's detail, use wallet_day) or what to do if the requested day is outside coverage.

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