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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description goes beyond that by disclosing the cost model — free within a daily allowance, then $0.003 USDC per call via x402 — which is genuinely useful behavioral context an agent cannot get from structured fields. It stops short of explaining allowance scope or payment failure behavior.

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?

Two short sentences, purpose first, cost second — front-loaded and free of filler. Both sentences earn their place, though the purpose sentence is minimal, leaving the definition terse rather than information-dense.

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?

An output schema exists, so return values need no explanation, and rich annotations cover the safety semantics; for a one-parameter read tool the burden is light. The remaining gap is sibling disambiguation — the description never distinguishes branches from direct-children/ultimate-parent or explains what a caller gets back conceptually.

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 100% and there is a single required 'lei' parameter, so the schema fully documents the input. The description adds no format, validation, or sourcing detail (where to obtain an LEI) beyond what the schema already provides, which is the baseline 3 case.

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 the resource ('Registered branches of an entity'), which is a meaningful clarification over the bare name 'branches' — it tells the agent this returns branch/establishment records for a legal entity. However, it uses no verb (list/get) and offers no differentiation from adjacent LEI siblings such as gleif__direct-children or gleif__ultimate-parent that also traverse entity structures.

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 only guidance given is commercial ('Free within the daily allowance, then $0.003 USDC per call'), not task-oriented. Nothing says when to call this versus gleif__lookup, gleif__direct-children, or a search tool, and no prerequisites (e.g. needing an LEI already in hand) are stated.

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