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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false. The description adds valuable context beyond annotations: data source (OECD SDMX API), licensing (CC BY 4.0), no authentication required, unlimited usage, and typical publication lags (2–4 weeks). This helps an agent understand data freshness and access requirements.

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?

The description is informative but not overly verbose. It front-loads the purpose, then covers coverage, frequency, lag, breakdown, and source. Each sentence adds value, and the structure is logical. Slightly long but efficient.

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?

Given the output schema exists and annotations cover safety, the description provides sufficient context: data source, licensing, coverage, frequency, lag, and breakdown. It doesn't explain pagination or return structure, but the output schema handles that. For an agent to decide whether to use this tool and invoke it correctly, it's 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 coverage is 100%, and each parameter (country, start_period, end_period, max_series) has a clear description. The tool description adds context about what the data represents (all-items CPI growth rate, expenditure breakdown) but doesn't go into parameter-specific syntax beyond the schema. 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?

States a specific verb ('Get') and resource ('CPI data and year-on-year inflation rates for any OECD country'). It clearly distinguishes from other CPI tools by specifying OECD scope and mentions the specific classification (COICOP 1999). This makes it easy for an agent to select it when the user requests OECD inflation data.

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?

The description explicitly states it covers all 38 OECD members plus selected non-members, implying it's the right tool for OECD countries. However, it does not explicitly mention alternatives (e.g., BLS for US, Eurostat for EU), so an agent might not know when to prefer another tool. Still, the OECD scope is a clear usage signal.

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