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

Annotations already declare readOnlyHint, idempotentHint and non-destructive behavior, so the safety profile is covered. The description adds the conceptual model of the edge directions, which is useful, but says nothing about result volume, pagination, or how edges are shaped (deferred to the output schema). Adequate but not rich.

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 sentences, zero filler, with the core concept front-loaded and the sibling routing placed last as a disambiguation. Every clause earns 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-value explanation is unnecessary; with that in mind the description covers purpose, both direction modes, and cross-tool routing. Nothing an agent needs to invoke this correctly is missing.

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%, including an explicit definition of 'in' vs 'out' and a worked ELI example, so the schema carries the parameter burden. The description reinforces direction semantics but adds no syntax or constraint beyond what the schema states.

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 a specific resource ('edges between instruments') and concretely illustrates what those edges mean (transposition, implementation, amendment) with the direction semantics. It also explicitly names the sibling it is not (find_national_implementations) and the granularity boundary, so an agent can distinguish it without opening schemas.

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 gives an explicit routing rule: use this for instrument-level links, use find_national_implementations for article-level links. The direction values are also tied to concrete use cases ('which national laws transpose a directive' vs 'what an instrument implements/amends'), so the agent knows which mode to pick.

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