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 still adds real value by disclosing what the response enriches beyond the raw document: cited Strasbourg case law, domestic law at issue, and judges. It stops short of stating failure behavior or whether full text is returned.

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?

A single front-loaded clause with zero filler and the selector named immediately. It is mildly telegraphic ('One HUDOC document') and lacks a verb, but nothing is wasted and nothing is padded.

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 one-parameter read tool with no output schema, the main open question an agent would have is what exactly comes back (full text vs. metadata plus the listed enrichments) and how misses are signalled. The description hints at the enrichment but leaves that gap, which is acceptable yet not complete.

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%, and the schema itself supplies the id format example ('001-219403') and provenance ('from a search hit'). The description only restates that the call is keyed on `itemid`, adding no syntax or constraint beyond the schema, so baseline 3 applies.

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?

Names a specific resource (a single HUDOC/ECHR document) and the exact selector (`itemid`), and distinguishes itself implicitly from the sibling `ua_echr__search` by being the single-document fetch. The verb is elided ("One HUDOC document") rather than stated, so it is clear but not maximally explicit.

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?

Usage is only implied: 'by `itemid`' plus the schema note that the id comes from a search hit tells an agent this is the follow-up call to `ua_echr__search`. There is no explicit when-to-use, no statement that a search must precede it, and no mention of what happens with an unknown or stale id.

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