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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds context annotations cannot express: one API request per company counts against the rate limit, an authenticated account is required, and INSUFFICIENT_DATA must never be read as clean. That last caveat is exactly the kind of misuse-preventing behavioral detail this dimension rewards.

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?

Four dense sentences: batching scope and output shape first, then the critical interpretation caveat, then use cases, then the operational constraints. Nothing is redundant with structured fields and nothing is padding.

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?

Output schema exists, yet the description still surfaces the row shape for at-a-glance planning; auth, rate-limit cost, batch ceiling, and the INSUFFICIENT_DATA pitfall are all covered. 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 coverage is 100% and the nested ico/country semantics (including the country tie-break warning) are fully documented in the schema. The description only restates the 25-item cap already present as maxItems, adding no new parameter meaning. Baseline 3 applies.

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 (run kyb_check) against a bounded resource (up to 25 companies) and enumerates the returned row fields (status, insolvency, sanctions, debts, verdict, coverage). It also implicitly distinguishes itself from the single-company kyb_check sibling, so an agent can choose without opening the schema.

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?

'Use for supplier lists or portfolios' gives a concrete triggering scenario, and the single-vs-batch relationship to kyb_check is implied by 'Run kyb_check on up to 25 companies at once.' No explicit 'use X instead when...' exclusion is stated, so it stops short of a 5.

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