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

No annotations are provided, so the description carries the full behavioral burden. "Returns" correctly signals a read-only retrieval, and the enumerated field list is genuinely useful since there is no output schema. However, it says nothing about permissions, rate limits, or whether citing mutates/records anything, leaving real behavioral gaps for a zero-annotation tool.

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, front-loaded with the return payload and followed by the usage trigger. The field enumeration is long but earns its place because no output schema exists to carry it.

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 must describe the return shape, and it does so concretely (status, effective date, instrument, article, penalty, sources, tense computation time). Combined with the complete single-parameter schema, an agent has enough to call it correctly; only behavioral caveats are 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?

There is one required parameter (id) at 100% schema coverage, and the schema fully documents it with an example ("eu-art50") and a pointer to lunara_obligations for discovery. The description adds no parameter-level detail beyond the schema, so the baseline 3 is appropriate.

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 verb+resource ("Returns a citation block for one obligation") and enumerates exactly what the block contains, so the agent knows this is a citation/evidence-retrieval tool rather than a listing or verification one. It does not name any sibling (e.g. lunara_obligations or lunara_verify) to sharpen the boundary, so it stops short of a 5.

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?

"Use this when you are about to state a regulatory date or requirement to someone, so the claim carries its source" gives a clear situational trigger. It does not name an alternative tool or state when NOT to use this one, so it lacks the exclusion/alternative element required for a 5.

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