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

Annotations already indicate read-only, idempotent, and closed-world behavior. The description adds valuable behavioral context: unknown facts keep checks in the list rather than dropping them, cash-basis shortens the list, and the tool makes no judgment on correctness. No contradiction with 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?

The description is front-loaded with 'START HERE' and every sentence carries essential information: what it returns, when to call, how partial facts are handled, cash-basis behavior, and its non-judgmental nature. No filler or redundancy.

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?

Despite having no output schema, the description thoroughly explains the output structure (checks grouped by dimension, where to look, innocent explanations, cost) and covers behavioral constraints. With 10 optional parameters, it gives enough context for an agent to invoke the tool successfully.

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% with detailed parameter descriptions, so baseline is 3. The description adds meaningful parameter-agnostic guidance: partial facts are acceptable and unknown facts don't drop checks, which tells the agent that omitting optional params is safe and expected. This raises the score to 4.

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?

The description states a specific action: 'return the bookkeeping checks that apply to it, grouped by dimension,' with clear output contents. It also distinguishes this tool from siblings like score_books_health and explain_books_check by explicitly saying it never says books are correct, only what to look at.

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?

Explicit usage guidance: 'START HERE for a books health check' and 'Call it immediately with partial facts rather than interviewing the user first.' It also provides exclusions: 'This never says whether books are correct' and mentions cash-basis businesses get a shorter list, which helps the agent decide when to use it.

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