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

Annotations already declare readOnlyHint=true and openWorldHint=false, but the description adds substantial behavioral context beyond them: publication lag, referenceDate/referenceIsToday semantics, Monday behavior, totalUsdM aggregation rules, and null netFlowUsdM handling with lastReportedDate. These details materially affect interpretation of the returned data.

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 front-loaded and dense with useful information, with no filler. However, it is a long single paragraph and could be more scannable if the data-lag and field semantics were structured separately from the asset list.

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 carries the burden of explaining return semantics, and it does so thoroughly: referenceDate, referenceIsToday, totalUsdM, netFlowUsdM nullability, lastReportedDate, and the distinction from per-fund data. An agent has enough context to call and interpret this tool correctly.

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?

There are zero input parameters, so the baseline is 4. The description does not need to explain input parameters, and it instead spends space on output-field semantics, which is appropriate for this tool.

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 states a specific verb and resource: get latest-day net ETF inflow/outflow in USD millions for every tracked crypto asset. It enumerates the covered assets and explicitly distinguishes this asset-level total view from get_fund_flows (per-fund breakdown) and get_funds (net assets), so an agent can identify it without opening schemas.

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?

It clearly explains when to use this tool and routes to alternatives: per-fund breakdown is get_fund_flows and net assets is get_funds. It also gives important timing context, including that data is one business day in arrears and Monday data is Friday's, which directly affects when an agent should call it and how to interpret results.

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