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

Annotations already declare readOnly/openWorld/non-destructive, yet the description adds real behavioral context: no API key required, universal currency scope, no forecast values returned (paywall), and the important distinction between 'no publisher covers this at all' versus 'covered but paywalled'. It also notes that any pair listed exists in the verified archive.

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?

Front-loaded with the core capability, but the text is repetitive: it states twice that no forecast values are returned and twice that subscription/API-key terms apply, and the opening sentence is a long run-on. Several sentences repeat information already established.

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?

The tool is fully specified for an agent: scope, access model, output nature, and the paywall ambiguity case are all covered, and an output schema exists so return shape need not be explained. The only shortfall is redundancy rather than missing information.

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 100% and the single optional currency parameter is already documented in the schema (omit for cross-currency summary, pass for per-indicator detail). The description adds only 'works for every served currency', 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?

Names a specific resource (forecast coverage catalogue) and enumerates exactly what it reports: which publishers forecast a currency's indicators, forecast class, consensus genuineness, and archive depth. This is clearly separable from siblings like event_predictions or data_catalogue, which return different content.

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?

Gives concrete triggering questions ('do you have the consensus for US CPI', 'what forecast do you have for payrolls') and states it works for every served currency with no API key. It does not explicitly name a sibling alternative to use instead, so it stops short of full when/when-not routing.

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