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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), and the description adds provenance (issuers' own daily files) plus a list of output contents (latest day, largest fund, last 5/30 days, total holdings). However, it does not clarify how the `days` parameter interacts with the fixed 5/30-day windows, leaving some behavioral ambiguity.

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?

A single dense sentence front-loads the tool's purpose, then adds output details after a colon. There is no wasted wording, though the run-on nature and the ambiguous list of windows could be clearer.

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?

For a read-only data tool with no output schema, the description does explain what data is included. However, it does not fully reconcile the `days` parameter with the described fixed 5/30-day windows, leaving an agent uncertain about exactly what the response will contain when `days` is changed.

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%, so both parameters are already documented. The description adds meaning for `asset` by explaining that ALL aggregates every coin in US dollars, but it introduces potential confusion by mentioning fixed 5- and 30-day windows alongside a variable `days` parameter (5–90).

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 (get net flows) and resource (US spot ETF flows), and clarifies scope: one coin or ALL, sourced from issuers' daily files. The description also lists the included data points, distinguishing it clearly from metric, price, and derivatives siblings.

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?

The description implies usage for ETF flow data and explains the ALL option for aggregating every coin, but it does not explicitly state when to choose this tool over alternatives or provide exclusions. No direct alternative exists in the sibling list, limiting the need, but guidance remains implicit.

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