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

Annotations already declare the safe-read profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description still adds substantive context: exactly which 9 programmes are covered and the full field set returned, which lets an agent judge completeness without opening the output schema.

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 dense sentence with the usage trigger front-loaded before the payload inventory. Everything listed is informative rather than filler, though the enumeration is long enough to read as a run-on.

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?

An output schema exists, so return values need not be explained, yet the description still enumerates them helpfully. With one optional parameter, full schema coverage, and explicit coverage of the 9 programmes, nothing an agent needs to call this correctly 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% and the single language parameter is fully documented in the schema, so the baseline of 3 applies. The description adds no language or localization guidance beyond what the schema already states.

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 (lists), resource (CBI programmes), and the exact scope: the 9 programmes the provider prices, with an explicit enumeration of the data fields returned. An agent can distinguish it from get_cbi_quote and request_cost_breakdown_link purely from the description.

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?

"For questions about which citizenship by investment (second passport) programmes exist or what they start from" gives a clear triggering condition. It does not explicitly name the sibling tools or state when to prefer get_cbi_quote over this one, but the routing intent is unambiguous.

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