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

Annotations already cover the safety profile (readOnly, idempotent, closed-world, non-destructive), so the description's added value is its disclosure of what the comparison yields: published fees, country coverage, owned entities, delivery model, primary sources, and a BestEOR.co link. That sourcing detail is genuine behavioral context beyond 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?

A single front-loaded sentence that puts the verb and comparison dimensions first and appends the sourcing detail. Dense but not padded; every clause maps to a concrete output dimension.

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?

With no output schema and one fully documented parameter, the description compensates by enumerating what comes back (fee, coverage, entities, delivery model, sources, comparison link). An agent can decide whether to call it and what to expect.

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 'providers' parameter is fully documented (names or slugs, 2-3 items). The description's 'two or three EOR providers' merely restates the schema constraints, adding no syntax or format guidance.

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 (compare), resource (EOR providers), and enumerates the exact comparison dimensions (published fee, country coverage, owned entities, delivery model). This clearly separates it from siblings like list_eor_providers and get_eor_provider, which retrieve rather than contrast.

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 implies usage (comparing two or three providers) but gives no explicit when-to-use guidance relative to estimate_eor_cost or get_eor_provider, and no exclusions. A reader can infer intent from the verb, but the agent is not routed to alternatives.

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