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

Annotations already establish readOnly/idempotent/non-destructive, so the bar is lower, and the description still adds real context: counts are read at query time from the SSOT, an API key at Legend tier or above is required, and GLOBAL is refused. It does not cover rate limits or cost, but the auth and freshness disclosures are substantive.

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?

It is one dense paragraph packing several distinct facts (brief contents, region taxonomy, day-rate handoff, SSOT freshness, auth tier) with no structural breaks, which makes it slow to scan. Most sentences do carry information, but the whole could be split and front-loaded more aggressively.

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 described. With that removed from scope, the description covers inputs, region semantics, refusals, data source, auth tier, and the alternative for day rates — everything an agent needs to call it correctly.

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 schema already defines both enums and the home_region bridge semantics, so the baseline is 3. The description adds value beyond the schema by clarifying the six-value geography (EMEA includes the Middle East, AFRICA is standalone, GLOBAL is the country-unknown bucket) and why GLOBAL is invalid as a target.

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 deliverable (a pre-subsidiary-opening brief) and enumerates its sections: providers by kind/country with LOCAL vs multi-region split, SAP end-customers by country/industry, live opportunities, and bridge groups. It explicitly distinguishes itself from the sibling that handles a related need (get_day_rate_benchmark) and from row-level tools by noting counts 'never rows'.

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 clear when-to-use context (reading a brief before opening a subsidiary in another region) and routes the adjacent need elsewhere: 'Day rates are NOT in this brief: call get_day_rate_benchmark per country.' It also states an explicit exclusion (GLOBAL is refused as a target region) and explains the home_region omitted-vs-set behavior.

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