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

With no annotations, the description carries the full burden. It usefully discloses that results are partial ("not the full decisions or rules adopted by Peregrini") plus credential (none) and cost (free), which is genuine behavioral value. However it omits read-only confirmation, result format, and any pagination or rate-limit 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?

Four short sentences with the core capability front-loaded after the intent framing. The credential/cost line is standard boilerplate for this tool family and earns its place. The opening quoted query is slightly odd but not wasteful.

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 2-param, no-output-schema, no-annotation search tool, the description covers what is returned (summaries + links), their limited nature, and access terms. It still leaves the `q` parameter and result structure unexplained, so an agent cannot fully predict invocation behavior.

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 0%, so the description must compensate. It implicitly maps to the `kind` enum by mentioning "case summaries" and "commentary" links, but the `q` search parameter is never explained (what it accepts, syntax, 240-char limit). Partial compensation only.

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 action ("Finds selected case summaries and links to official UNIDROIT commentary"), giving a clear verb+resource. It distinguishes itself from the full-text siblings (read_international_law) by framing results as summaries and links, though it never names the alternative explicitly. The leading quoted user-query sentence is awkward but does frame intent.

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?

"These are starting points for research" and "not the full decisions" imply this is a discovery tool to be followed by a full-text lookup, but no sibling is named (e.g. read_international_law). The when-to-use context is inferable rather than explicit, and there are no exclusions.

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