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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the agent knows it's a safe read from a closed data source. The description adds valuable behavioral context: it returns a time series of net USD millions per day with sign convention (positive = inflow, negative = outflow), and clarifies that figures are asset-level totals with no per-fund breakdown, pointing to an external source for per-fund data. This goes beyond the annotations, though it doesn't mention rate limits or pagination.

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 two sentences and front-loaded with the core purpose, then adds useful details without much waste. The second sentence includes a long list of slugs for per-fund tables, which is somewhat verbose but directly useful. It could be slightly more concise, but it remains clear and structured.

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?

Given the tool's simplicity (one required parameter, read-only, no output schema), the description provides sufficient context: it explains the return format (time series, USD millions, sign), scope (asset-level totals, no per-fund), and points to an external resource for more granular data. It lacks explicit mention of error conditions or exact response structure (e.g., array of {date, net_flow}), but that's a minor gap given the simplicity.

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 100% (the single asset parameter is fully described with an enum in the schema). The description does not add any parameter-specific meaning beyond what the schema provides; it only restates the asset concept. Baseline 3 is appropriate when the schema does the heavy lifting and the description adds nothing new.

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 states a specific verb and resource: 'Get daily net ETF flow history for a single crypto asset over the last 30 days.' It distinguishes the asset-level scope from sibling tools like get_flows_summary and get_weekly_analytics by explicitly describing its time granularity (daily, 30 days) and scope (single asset, no per-fund breakdown).

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 provides clear context for when to use this tool: for daily net ETF flow history of one asset over 30 days. It also implicitly differentiates from siblings by noting the 30-day daily granularity and asset-level totals. However, it does not explicitly state when not to use it or name alternative tools for per-fund data or longer time series.

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