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

Annotations already establish readOnly, idempotent, closed-world and non-destructive, so safety is covered. The description adds genuinely new behavior: it returns an itemized exact calculation with stated assumptions and flags discrepancies such as balance bills or mismatched totals, and it notes no names or identifiers are accepted. That return-shape and assumption disclosure matters because there is no output schema.

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?

Three sentences, front-loaded with what is computed, followed by when to use it and a scope/PHI boundary note. Every sentence carries information; only the closing "never names or identifiers" clause is slightly imprecise given the boolean and percentage parameters.

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 ten-parameter, all-optional arithmetic tool with no output schema, the description does the important work: it explains the computation, the reported outputs, the discrepancy detection and the assumptions. The one notable gap is minimum viable input — with no required parameters, an agent cannot tell from the description which amounts must be supplied for a meaningful recomputation.

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%, so each of the ten amounts is already documented, giving a baseline of 3. The description mostly restates the schema's field list rather than adding usage rules (e.g., which combinations are sufficient, how coinsurance_rate vs coinsurance_amount are reconciled). Its "dollar amounts only" claim also sits slightly awkwardly beside the in_network boolean and coinsurance_rate percentage parameters.

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 ("Recomputes one EOB line or claim total from the printed amounts"), enumerates the inputs it consumes, and names what it produces (contractual adjustment, expected patient responsibility and plan payment, discrepancy flags). This clearly separates it from siblings like explain_insurance_term and get_eob_reading_guide, which describe or explain rather than compute.

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 triggering condition: use when a user supplies EOB or bill amounts and asks whether what they owe is right. It also implicitly fences the tool ("pure arithmetic; takes dollar amounts only"), suggesting it is not for term definitions or document retrieval. It stops short of naming the alternative sibling for non-arithmetic questions, so it is clear context without explicit exclusions.

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