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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds meaningful behavioral context by explaining what 'in' and 'out' edges mean in legal terms and clarifying the granularity of results, without contradicting the annotations.

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 dense, front-loaded sentences with no filler. The core semantics and the distinguishing exclusion are each covered in one sentence, making every word 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?

For a read-only, two-parameter tool, the description provides the complete invocation contract: what the tool does, how to interpret both directions, and when to use a sibling. The lack of output format details is minor given the tool's simplicity and annotation coverage.

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 the baseline is 3. The description adds value by translating the generic direction enum into domain-specific semantics: 'in' relates to national laws transposing a directive, while 'out' relates to implementing/amending actions, which helps agents reason about expected results.

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 function precisely: returning relationship edges between instruments, with both directions explicitly explained. It also distinguishes itself from a sibling tool by the instrument-level scope ('for article-level links use find_national_implementations').

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?

Explicitly tells the agent when not to use this tool ('for article-level links use find_national_implementations') and clarifies the two direction modes. This is direct routing guidance to the correct sibling without requiring schema inspection.

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