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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds substantial context on top: counts are read at query time from the SSOT, Legend figures are counts and never rows, GLOBAL is rejected rather than silently empty, and authentication tier requirements are stated. Nothing about the call's behavior is left for the agent to infer.

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 purpose in the opening clause, and every sentence carries real information (region semantics, exclusions, auth, corpus provenance). It is dense and parenthetical-heavy, and the day-rate digression is longer than strictly necessary, but no sentence is filler.

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?

For a two-parameter read-only aggregate tool with an output schema, the description supplies everything the agent needs: what each section contains, how regions are defined, the prerequisite credentials, and which adjacent question requires a different tool. The output schema handles return shape, so no gap remains.

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 schema already documents home_region omission behavior, so this is mostly reinforcement. However the description adds genuine semantics beyond the schema: the six-value geography definitions (EMEA spans Europe AND the Middle East, AFRICA stands alone, GLOBAL is the country-unknown bucket) and the fact that GLOBAL is refused as a target, which the enum alone cannot convey.

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 concrete verb and resource ('one-call brief') and then enumerates the four payloads it returns: providers by kind/country with LOCAL vs multi-region-group split, SAP end-customers by country and industry, live opportunities by country, and bridge groups. It explicitly carves out what it does NOT return (day rates) and names the sibling that does, so an agent can separate it from get_day_rate_benchmark without opening either 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?

Names the decision context precisely ('the brief a services practice reads before opening a subsidiary in another region'), states the explicit exclusion and routes to the alternative (get_day_rate_benchmark per country, with its coverage caveat), and spells out the access prerequisite (MCP Pass or Firm account; Consultant and Legend web plans excluded). Both when-to-use and when-not-to-use are covered.

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