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

Annotations only cover the read-only/open-world safety profile; the description adds substantial behavioral detail on top: exact auth header forms, the three-valued `verified` flag with explicit guidance that `null` is not the same as disproven, the `tier` vocabulary, and the warning that page-level USD metrics must not be summed across pages. This is precisely the kind of context annotations cannot carry.

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?

Front-loaded with purpose, then access, then a structured Returns block with bullets — easy to scan. It runs long, but the length is largely earned because there is no output schema to carry the return-shape detail; only minor phrasing ('decorated with resolved display names') is expendable.

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 does the full job: it documents each return field, the three-valued evidence semantics, page-scoped vs site-wide metric caveats, and the distinct empty-list `meta` shape. An agent can interpret every response shape, including the empty and end-of-list cases, without further information.

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% and the schema's own descriptions for `limit` and `before` are already richer than anything the tool description adds about them. The description's cursor note ('Cursor for the next page, or null at the end') restates the schema rather than extending it, so the baseline 3 applies.

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: 'newest settlements across every indexed chain, payer to payee', plus the endpoint it wraps (GET /v0/flows) and the UI surface it mirrors. That implicitly contrasts with entity-scoped siblings like list_entity_settlements, but no sibling is named, so the differentiation is left to inference.

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?

Usage is implied rather than stated: 'the newest settlements' plus 'the same feed the /flows page renders' tells the agent this is the live global feed, and the API-key requirement is spelled out. But nothing says when to choose this over list_transactions or list_entity_settlements, and there are no exclusions.

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