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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds genuinely new behavioral context beyond the structured fields: the pricing model (free within a daily allowance, then $0.003 USDC per call via x402), which is real operational information an agent cannot get from annotations. It stops short of noting behavior when an entity has no parent.

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, front-loaded with what the tool returns and then the cost model. There is no filler and no sentence that fails to earn its place.

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 not be explained, and annotations cover the safety profile. The description supplies the missing piece an agent would care about — cost and the x402 payment path. It is only slightly short of complete in not covering the no-parent edge case.

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?

Only one parameter exists and schema description coverage is 100%, so the schema already carries the burden; the baseline of 3 applies. The description adds nothing about the lei argument (format, source, validity), and the schema's own description is merely the redundant string 'LEI'.

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 names the exact resource returned — the direct accounting parent of an entity — which is specific enough to distinguish it in spirit from gleif__ultimate-parent and gleif__direct-children. It does not, however, explicitly contrast itself against those siblings, so an agent must infer the direct-vs-ultimate distinction from the term 'direct' alone.

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?

There is no explicit when-to-use guidance and no alternatives named, even though gleif__ultimate-parent is an obvious competing choice for the same question. The only implied guidance is the tool's name and return noun, which leaves the agent to infer the selection rule.

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