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

Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: 'Information, not advice', data-freshness via 'last_verified', the 'postponed to mid-2026' ECCIRA status, the specific deadline example (St Kitts 31 Jul 2027), and the clarifying note that 'Citizenship is permanent; an expired passport is only a lapsed travel document'. These are substantive disclosures a caller could not infer from 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?

It is a single front-loaded paragraph with no filler sentences, but it devolves into a dense 130+ word enumeration of returned fields (fees, validity, processing, biometrics, ECCIRA, deadlines, source URLs). Because an output schema exists, much of that field-by-field enumeration is redundant with structured data that the agent can already read, making the description longer than its marginal informational value warrants.

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, single-parameter fact tool, the description covers everything an agent needs: covered jurisdictions, parameter behavior, data provenance ('official source URLs, last_verified', the Mirabello page), caveats ('Information, not advice'), and the key domain nuance that citizenship is permanent while the passport merely lapses. With annotations covering safety and an output schema covering return shape, nothing material 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%, so the baseline is 3. The description adds value by enumerating the six valid jurisdictions (St Kitts & Nevis, Antigua & Barbuda, Dominica, Grenada, St Lucia, Vanuatu), letting the agent know the valid domain of the country parameter without opening the schema, and restates the programme-id format and the omit-for-all behavior. It does not, however, map each country name to its programme id (e.g. st-kitts-cbi), so the added value is real but partial.

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 opens with a specific verb+resource+scope: 'CBI passport-RENEWAL facts for a Caribbean/Pacific programme country' and enumerates the six covered jurisdictions. It is clearly distinguishable from sibling tools like get_document_checklist, estimate_timeline, or estimate_malta_passport_fee (a different programme). An agent knows exactly what data domain this returns.

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 implied through the parameter instruction ('Pass country ... for one; omit for all six') and the renewal-vs-application framing, but the description never states explicitly when to prefer this tool over adjacent ones such as get_programme, get_document_checklist, or get_provenance, nor any when-not condition. Routing guidance is left to inference.

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