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

Annotations already declare the safe read profile (readOnly, idempotent, non-destructive), so the lower bar applies; the description still adds the 'or not-found' outcome, which the annotations do not convey. It does not mention auth or rate-limit behavior, so it stops short of 5.

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?

Two tight sentences: the usage condition and return fields come first, and the exclusion is appended as a short guardrail. No filler or restated name/title.

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 single-parameter read tool with annotations covering the safety profile and an output schema present, nothing needed to invoke it correctly is missing. Field enumeration is mildly redundant with the output schema but reinforces the invocation trigger.

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?

One parameter with 100% schema description coverage, including the 24-hex-char pattern, so the schema carries the full semantics. The description adds no extra meaning about businessId, which is the expected baseline when coverage is high.

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 and resource ('one business's invoicing setup') and enumerates the fields involved (currency, country, language, timezone), which cleanly separates it from the revenue/receivables siblings. The explicit 'Not for revenue or unpaid invoices' sharpens the boundary further.

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 an explicit trigger ('when someone asks about one business's invoicing setup') and names the exclusions, implicitly routing the agent to get_revenue_summary and get_receivables_summary instead. Both when-to-use and when-not-to-use are present.

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